Amorphous solid dispersions: An update for preparation, characterization, mechanism on bioavailability, stability, regulatory considerations and marketed products

Study on the acoustic emission frequency of salicylic acid crystal growth based on beam vibration

This study aims to investigate the relationship between the grain size of salicylic acid crystals and the frequency of acoustic emission signalsduring the crystallization of salicylic acid. During the crystallization process of salicylic acid, an acoustic emission system was utilized to monitor the emitted sound signals. Based on the beam vibration theory, a lateral vibration model of the crystals was constructed to study the correlation between acoustic emission signals and crystal grain size. This process occurs with one end of the crystal acting as a fixed end and the other as a free end. The study found that when the crystal grain size is between 100-300 µm, the characteristic frequency of the crystal is 115-344 kHz. Finite element analysis software was also employed to calculate the characteristic frequency of the crystal grain size, and the simulation results were highly consistent with the experimental data.

Case study: cremophor EL-based liquid formulations as simple substitutes for amorphous solid dispersions in early preclinical in vivo studies

OBJECTIVES

The objective of the present case study was to increase the exposure of the poorly soluble crystalline compound A.

METHODS

Mice received 10 mg/kg of crystalline compound A formulated in eight different cosolvent, oil, and cyclodextrin mixtures.

KEY FINDINGS

In all cases, AUC0-24h and maximum blood/plasma concentration (Cmax) were in the range of 6-16 µM × h and <1.4 µm, respectively, with a bioavailability below 18%. When 6% cremophor (CrEL) was added to three selected vehicles, AUC0-24h and Cmax increased ~5-10 times. The obtained pharmacokinetic profile of the most improved formulation using CrEL was possible to superimpose on the one obtained after administration of a CrEL-free amorphous solid dispersion (ASD, HPMC-AS:drug, 80:20) suspension of compound A.

CONCLUSIONS

It is crucial to find an optimal screen vehicle as early as possible for a poorly water-soluble lead series and then avoid time and resource-consuming vehicle testing of multiple compounds in vivo. An ASD approach is more suited for clinical development when more time and resources are allocated to the project. In this case study, some preclinical formulations were used to maximize exposure but also as preindicators for ASDs later in the development chain.

Monophasic coamorphous sulpiride: a leap in physicochemical attributes and dual inhibition of GlyT1 and P-glycoprotein, supported by experimental and computational insights

Study aimed to design and development of a supramolecular formulation of sulpiride (SUL) to enhance its solubility, dissolution and permeability by targeting a novel GlyT1 inhibition mechanism. SUL is commonly used to treat gastric and duodenal ulcers, migraine, anti-emetic, anti-depressive and anti-dyspeptic conditions. Additionally, Naringin (NARI) was incorporated as a co-former to enhance the drug's intestinal permeability by targeting P-glycoprotein (P-gp) efflux inhibition. NARI, a flavonoid has diverse biological activities, including anti-apoptotic, anti-oxidant, and anti-inflammatory properties. This study aims to design and develop a supramolecular formulation of SUL with NARI to enhance its solubility, dissolution, and permeability by targeting a novel GlyT1 inhibition mechanism, extensive experimental characterization was performed using solid-state experimental techniques in conjunction with a computational approach. This approach included quantum mechanics-based molecular dynamics (MD) simulation and density functional theory (DFT) studies to investigate intermolecular interactions, phase transformation and various electronic structure-based properties. The findings of the miscibility study, radial distribution function (RDF) analysis, quantitative simulations of hydrogen/π-π bond interactions and geometry optimization aided in comprehending the coamorphization aspects of SUL-NARI Supramolecular systems. Molecular docking and MD simulation were performed for detailed binding affinity assessment and target validation. The solubility, dissolution and ex-vivo permeability studies demonstrated significant improvements with 31.88-fold, 9.13-fold and 1.83-fold increments, respectively. Furthermore, biological assessments revealed superior neuroprotective effects in the SUL-NARI coamorphous system compared to pure SUL. In conclusion, this study highlights the advantages of a drug-nutraceutical supramolecular formulation for improving the solubility and permeability of SUL, targeting novel schizophrenia treatment approaches through combined computational and experimental analyses.

Amorphous Roxithromycin Loaded in-situ Gel for the Treatment of Staphylococcus aureus Induced Upper Respiratory Tract Infection

Objective

Upper respiratory tract infections are among the most prevalent respiratory diseases, imposing both financial and physical burdens on affected individuals. Roxithromycin (ROX), a primary drug for treating bacterial-induced respiratory tract infections, is typically administered orally due to its hydrophobic nature. However, the non-specific distribution resulting from oral administration reduces bioavailability and can cause side effects such as diarrhea.

Methods

In this study, we prepared a thermo-sensitive in-situ gel using a facile and highly reproducible method by simply mixing two types of poloxamers with ROX.

Results

The ROX can be well dissolved in the poloxamer matrix in amorphous state to give solution. Upon intranasal administration, the ROX solution undergoes a phase transition to form in-situ gel under body temperature. This gel remains in the nasal cavity for an extended period, releasing the drug directly to the site of infection and minimizing non-specific distribution. Pharmacokinetic experiments revealed that, compared to oral administration, the bioavailability of local nasal administration increased by 1.5 times, and the drug concentration in the local nasal cavity increased by 8 times. In contrast, concentrations in the liver and small intestine did not significantly differ from those following oral administration. In vivo antibacterial experiments also showed that the ROX in-situ gel has superior antibacterial efficacy and excellent biocompatibility.

Conclusion

These results suggest that the thermo-sensitive ROX in-situ gel is a promising formulation for treating bacterial upper respiratory tract infections.

Enhancing Efavirenz Bioavailability Via Polymer-Based Buccal Administration: Optimization and Characterization of Nanocrystal-Loaded Dissolving Microneedle Delivery Systems

Efavirenz (EFV) is a widely utilized antiretroviral agent in HIV/AIDS therapy that is known for its efficacy but is also associated with various side effects. For improved drug delivery, buccal administration offers a promising alternative by allowing the drug to enter the systemic circulation directly through the oral mucosa, bypassing the gastrointestinal tract and first-pass metabolism. This study explored the interaction between EFV and different polymers through molecular docking, revealing a strong binding affinity to Pluronic®F-127 (-2.1 kcal/mol). EFV was formulated into nanocrystals (EFV-NC) using Pluronic®F-127 as the stabilizer, characterized by an average particle size of 174.83 ± 15.21 nm, a narrow size distribution (PDI of 0.15 ± 0.013), and good stability (zeta potential of -22.27 ± 1.12 mV). FTIR and XRD analyses revealed polymer-induced alterations in the crystalline structure of the EFV. The EFV-NC formulation enhanced the solubility (up to 400 µg/mL) and achieved 89.58 ± 4.01% drug release within 24 h, following the Higuchi model kinetics for controlled release. EFV-NC-loaded dissolving microneedles (EFV-NC-DMN) demonstrated robust mechanical properties, efficient tissue penetration, and minimal moisture absorption. Ex vivo and in vivo studies revealed that compared with oral EFV, EFV-NC-DMN provided a relative bioavailability of 137.40%, with higher plasma concentrations and prolonged release, highlighting its potential for superior HIV/AIDS management via buccal administration and improved therapeutic outcomes.

Development and characterisation of polymeric solid dispersed systems of hesperidin, obtained by centrifugal fibre formation

The flavonoid hesperidin is a crucial, biologically active substance of great interest because of its polypharmacological properties and high safety profile. However, its widespread use of this bioflavonoid in remedies for the treatment and prevention of various diseases is limited by its low water solubility. This study reports on solid dispersed systems (SDSs) of hesperidin, fabricated for the first time via the method of centrifugal fibre. For one of the compositions of these SDSs, the solubility of the flavonoid in water is observed to be 150-170 times higher than that of the pure compound. Polyvinylpyrrolidones, with different molecular weights, was used as a fibre-forming polymer carrier, alongside sucrose and mannitol as auxiliary substances to enhance the yield of the composites. The SDSs of hesperidin in the form of fibres were characterised via differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD). DSC and PXRD results confirmed the amorphisation of hesperidin in the fibrous SDSs. FTIR results confirmed that the interaction of hesperidin with the components of the SDS composites occurs due to the formation of intermolecular hydrogen bonds. Studies of in vitro release kinetics in buffer media with pH = 1.2, 4.5 and 6.8 showed that the release rate of hesperidin from the centrifugally formed SDSs is considerably higher than the dissolution rate of pure hesperidin. Thus, the results of this study confirm that centrifugal fibre formation is a simple and effective method for fabricating highly soluble SDSs of hesperidin.

A review of precision medicine in developing pharmaceutical products: Perspectives and opportunities

Over the next decade, Precision Medicine (PM) is poised to become the standard of care in pharmaceutical therapy, necessitating a fundamental transformation in the design and development of innovative custom-made drug products. To date, a comprehensive review linking PM with practical personalized drug formulations is missing. This review attempts to provide an overview of state-of-the-art formulation approaches capable of translating PM evaluation and resulting recommendations (clinical research) into tailored drug products (non-clinical research) for real-world patients. Comprehensive literature searches in four scientific databases (Scopus, SciFinder, Web of Science, and PubMed) were performed. Current approaches to point-of-care PM formulations and needs-based locally distributed manufacturing presently under research & development (R&D) as alternatives to conventional large-scale manufacturing of one-size-fits-all drug products are discussed. The following methods were identified as the most promising PM formulation strategies: tablet splitting, liquid dispensing, compounding pharmacies, additive manufacturing, drug impregnation, drug extrusion, and orodispersible films (ODFs). The challenges and opportunities of current state-of-the-art formulation technologies that can enable making PM routinely accessible in practice settings will be discussed. Additionally, light will be shed on point-of-use manufacturing (Pharmacy on Demand) as an uncharted territory for PM and its pathway towards practical implementation.

Characteristics of Tylvalosin Tartrate Enteric Amorphous Pellets Prepared by Liquid Layering

PURPOSE

Tylvalosin Tartrate (TAT), a new-generation macrolide antibiotic, undergoes significant degradation in the stomach and in vivo rapid elimination upon oral administration, resulting in poor bioavailability. This study developed TAT enteric amorphous pellets by liquid layering (TAT/EAP-LL) with pH-sensitive and burst release characteristics, to enhance drug stability in the stomach and concentration enrichment in the duodenum.

METHODS

The drug loading layer, isolation layer and enteric layer were formed on the surface of the blank core pellets. Investigation into the characteristics of TAT/EAP-LL revealed that stable amorphous solid dispersions in the drug loading layer were formed by liquid layering. Then, DSC analysis confirmed that triethyl citrate significantly improved the film-forming properties of Methacrylic-ethyl acrylate copolymer. Additionally, TAT/EAP-LL was confirmed to exist in the amorphous state by DSC、PXRD and PLM.

RESULTS

In vitro, TAT/EAP-LL demonstrated a similar 4.07% release within 2 h at pH 1.0 as TAT enteric pellets (TAT/EP-LL) and a much faster burst release at pH 6.8, with complete release within 15 min. In vivo, the oral bioavailability of TAT/EAP-LL was improved to 1.71 times compared to commercial formulations and 1.47 times compared to TAT/EP-LL.

CONCLUSION

This study offers a novel platform for the enhanced oral delivery of TAT and proposes effective formulation strategies for pulsatile drug delivery.

Amorphous solid dispersions of amphiphilic polymer excipients and indomethacin prepared by hot melt extrusion

Improving the solubility of poorly water-soluble drugs is essential for enhancing bioavailability, formulation flexibility and reducing patient-to-patient variability. The preparation of amorphous solid dispersions (ASDs) is an attractive strategy to formulate such drugs, leading to higher apparent water solubility and therefore higher bioavailability. For such ASDs, water-soluble polymer excipients, such as poly(vinyl pyrrolidone) (PVP) or poly(vinyl pyrrolidone-co-vinyl acetate) (P(VP-co-VA)), are employed to solubilize and stabilize the drug against crystallization. We posit that polymers bearing tertiary amides are particularly well suited to stabilizing drugs containing H-bond donors, as they offer strong H-bonding potential between the polymer and drug. The aim of this study was to compare new and established polymers with tertiary amides as excipients for ASDs. Experimental amphiphilic ABA triblock copolymers comprising poly(2-methyl-2-oxazoline) (pMeOx), poly(2‑butyl‑2-oxazoline) (pBuOx) and poly(2‑butyl‑2-oxazine) (pBuOzi) blocks, were compared with the established excipients, PVP and P(VP-co-VA). ASDs with indomethacin as the model drug were prepared at high drug loadings via hot melt extrusion. The extrudates were studied with DSC and PXRD, revealing the ASDs to be fully amorphous up to 75wt% indomethacin, independent of the polymer used. 13C CPMAS NMR provided insights into intermolecular associations as a function of drug loading, and suggested the presence of drug dimers at 75wt% drug loading in pMeOx-pBuOzi-pMeOx and pMeOx-pBuOx-pMeOx, which could affect physical stability. Independent of the polymers, the solid-state form of the drug in the ASD was found to affect the dissolution profile of the samples, insofar as the samples containing crystalline indomethacin showed slower dissolution than the fully amorphous ones. This study shows that the polymers comprising poly(2-oxazoline) and poly(2-oxazine) are effective polymers for ASD preparation, similar to PVP and P(VP-co-VA) which merits further investigations into these novel polymers for formulating ASDs.

Solid dispersion of alectinib HCl: preclinical evaluation for improving bioavailability and establishing an IVIVC model

OBJECTIVE

Alectinib HCl (ALB-HCl) is a BCS class IV molecule with low solubility and low oral bioavailability. Owing to its low bioavailability, a high dose of ALB-HCl is recommended with food to meet clinical efficacy. Thus, there is a need for a delivery system to overcome the bioavailability concerns.

METHODS

Three solid dispersion (SD) formulations (I, II, and III) were evaluated for in-vitro dissolution and in-vivo pharmacokinetics (PK) study in Wistar rats. An in-vitro and in-vivo correlation (IVIVC) model was developed to establish a relationship between in-vitro dissolution data and in-vivo PK data. The formulations were subjected to stability studies.

RESULTS

All formulations showed enhanced dissolution in all the media except Formulation I in FaSSIF media. In-vivo PK studies displayed that Formulation I was inferior to API alone. Formulations II and III (amorphous SD [ASD]) exhibited two-fold higher Cmax and AUC0-last than API alone. Level A IVIVC model was established for Cmax and AUC0-last with an acceptable % prediction error (PE). When evaluated for external predictability, the model was found validated for Cmax (% PE <10%), however, it was inconclusive for AUC0-last (%PE -14.03). Stability studies showed ASD formulations were stable during storage.

CONCLUSION

A stable ASD formulation of ALB-HCl was successfully developed with improved bioavailability. Developing an IVIVC model can act as a surrogate to predict in-vivo performance. The selection of formulation components in ASD shall be rationalized for bioavailability and stability before clinical evaluation.

Scale-up and clinical bioavailability assessment of a 45% drug loaded amorphous nanoparticle formulation of a BCS IV compound for oral delivery

A 45 % drug loaded (DL) amorphous nanoparticle (ANP) formulation for a BCS IV drug demonstrated promising pharmacokinetics in dogs (Purohit, et al., J. Pharm. Sci. 2023(113)1007-1019). This preclinical data enabled a human proof-of-concept assessment opportunity. The ANP freeze dried powder for oral suspension was prepared using solvent/antisolvent precipitation followed by organic solvent removal and freeze drying (FD). Challenges manifested during scale-up from 50 g to 280 g. Given the preclinical data, formulation change was restricted, therefore, process modifications were implemented. Cold collection after precipitation prevented particle growth but resulted in 75 nm particles at clinical scale (CS), compared to 150 nm at laboratory scale (LS). This size decrease rendered stabilizer amounts suboptimal for FD operation. Consequently, when FD powder was resuspended in water a smaller fraction of particles was below 450 nm (by filtration), ∼65 % for CS compared to ∼85 % for LS. Formulation was stable for > 6 months, evaluated by monitoring moisture content, assay, powder X-ray diffraction (PXRD), and redispersion time. Despite ∼65 % re-dispersibility, this 45 % DL formulation in humans had higher Cmax and AUC ∼73 % and ∼46 % respectively in fasted-state, and under fed-state it met bioequivalence criteria for AUC but Cmax was 20 % lower compared to reference (10 % DL ASD tablets) demonstrating advantage of ANP strategy over ASD approach.

Understanding the effect of plasticizers in film coat materials on the physical stability of amorphous solid dispersions

Amorphous solid dispersions (ASDs) have been extensively utilized to improve the bioavailability of drugs that have low aqueous solubility. The influence of different excipients on the conversion of amorphous drugs into their crystalline forms in ASDs has been extensively researched. However, there is limited knowledge examining the impact of film coating materials on the physical stability of oral tablet formulations containing ASDs. In this study, we demonstrate that plasticizers present in film coats can have a detrimental impact on the physical stability of ASDs. We systematically compared two frequently used plasticizers in film coats: triacetin and polyethylene glycol 3350 (PEG 3350). To gain mechanistic insights into the detrimental effects of plasticizers on the physical stability of ASDs, plasticizer leaching studies and physical stability studies of solvent-evaporated and spray-dried intermediates (SDI) using two BCS class II drugs were conducted. Triacetin was found to leach into the tablet core within one week when stressed at 40 °C/75 % RH, whereas no leaching was observed for PEG 3350, as discerned from spectroscopic studies. We also found that triacetin-containing ASDs exhibited greater amorphous to crystalline form conversion of the drug compared to PEG 3350-containing ASDs after stability testing. Moreover, the incorporation of triacetin into polymers was found to cause a significant depression of glass transition temperature and upon equilibration with moisture, a drop below room temperature. Overall, these observations underscore the importance of carefully selecting plasticizers to be present in film coatings when developing ASD pharmaceutical products.

Investigating the effects of formulation variables on the disintegration of spray dried amorphous solid dispersion tablets

Amorphous solid dispersion (ASD) tablets based on hydrophilic polymer carriers may encounter disintegration challenges. In this work, the effect of different formulation composition variables on the ASD tablet disintegration performance was systematically studied. GDC-0334: copovidone (PVPVA) 60: 40 ASD prepared by spray drying was selected as the model ASD system. The effects of ASD loading, filler type and ratio, disintegrant type and level were then investigated using tablets made by direct compression process. Tablet disintegration time increased with the increase of ASD loading, especially when ASD loading exceeded 50 %. At the same tablet solid fraction, when lactose was used as the soluble filler, faster tablet disintegration was observed compared to the tablets with mannitol as the soluble filler. Among the three tested disintegrants, croscarmellose sodium performed the best in facilitating the ASD tablet disintegration, followed by sodium starch glycolate, and crospovidone was the poorest. When croscarmellose sodium was used as the disintegrant, 5 % level was sufficient to enable ASD tablet disintegration at 60 % ASD loading and further increase of croscarmellose sodium level to 8 % did not provide additional benefit. Water uptake experiments were performed on selected tablets and the results demonstrated a positive correlation with tablet disintegration time, indicating water penetration is a major contributing step for the disintegration of our ASD tablets. Overall, this work provides a rationale for excipient selection and insights into building a platform formulation approach for developing immediate-release ASD tablets.

Continuous twin-screw melt granulation of drug-loaded electrospun fibers

Electrospinning (ES) is a promising continuous formulation strategy to produce amorphous solid dispersions (ASDs) and thereby improve the dissolution of poorly water-soluble drugs. However, processing the electrospun material into solid dosage forms (e.g. tablets) is challenging due to the poor flow properties. In this research, continuous twin-screw melt granulation was applied to improve the flowability of the fibers and therefore ease the further processing steps. During this work, two ASD compositions were investigated: one containing 60 % poly-vinylpyrrolidone-vinyl acetate 6:4 copolymer and 40 % itraconazole (ITR), and another one containing hydroxypropyl methylcellulose (HPMC) and ITR in the same ratio. Both fiber compositions were granulated with polyethene glycol as the binder material, while the effects of the process parameters were examined. The application of higher granulation temperature and screw configurations with increased shear forces compromised the fibrous structure, induced crystallization of the ASD, and decreased the dissolution. However, the stability of the ITR-HPMC fibers proved to be higher as their granulation at 60 °C led to granules with adequate flow properties and dissolution. Moreover, tablets with fewer excipients were pressed from them, resulting in a 34 % reduction in weight. Consequently, this process can complement ES technology and facilitate its industrial implementation.

Targeted delivery of a selenium-sulfa compound via cationic starch microparticles: Modulation of oxidative stress and pain pathways in fibromyalgia-like symptoms in mice

Cationic starch microparticles (CStMPs) loaded with 4-amino-3 -(phenylselenyl)benzenesulfonamide (4-APSB) were prepared and investigated in a model of fibromyalgia (FM) induced by intermittent cold stress (ICS) in male and female Swiss mice. The CStMPs/4-APSB were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, zeta potential, and particle size measurements, providing information about their chemical composition, surface charge, morphology/microstructure, and size (1.50 ± 0.5 μm). Following ICS exposure, the animals were treated with free 4-APSB (1 mg/kg), CStMPs/4-APSB (containing 0.13 mg of 4-APSB per mg of microparticles), or CStMPs, from days 5 to 10. The results revealed the successful incorporation of 4-APBS in the CStMPs. Free 4-APSB and CStMPs/4-APSB reversed nociceptive- and depressive-related behaviors in male and female mice exposed to ICS, attenuating the hallmark symptoms of FM. Those treatments (free 4-APSB and CStMPs/4-APSB) normalized the monoamine oxidase (MAO)-A activity in the cerebral cortex and the oxidative damage, providing the correct functioning of the enzyme Ca2+ -ATPase in the cerebral cortex and hippocampus of mice exposed to ICS. The CStMPs/4-APSB modulated the oxidative stress markers, specifically in the spinal cord of mice - an anatomical region intricately linked to pain pathways.

Mechanistic Insights into Amorphous Solid Dispersions: Bridging Theory and Practice in Drug Delivery

Improving the bioavailability  of poorly water-soluble drugs presents a significant challenge in pharmaceutical development. Amorphous solid dispersions (ASDs) have garnered substantial attention for their capability to augment the solubility and dissolution rate of poorly water-soluble drugs, thereby markedly enhancing their bioavailability. ASDs, characterized by a metastable equilibrium where the active pharmaceutical ingredient (API) is molecularly dispersed, offer enhanced absorption compared to crystalline forms. This review explores recent research advancements in ASD, emphasizing dissolution mechanisms, phase separation phenomena, and the importance of drug loading and congruency limits on ASD performance. Principal occurrences such as liquid-liquid phase separation (LLPS) and supersaturation are discussed, highlighting their impact on drug solubility, absorption and subsequent bioavailability. Additionally, it addresses the role of polymers in controlling supersaturation, stabilizing drug-rich nanodroplets, and inhibiting recrystallization. Recent advancements and emerging technologies offer new avenues for ASD characterization and production and demonstrate the potential of ASDs to enhance bioavailability and reduce variability, making possible for more effective and patient-friendly pharmaceutical formulations. Future research directions are proposed, focusing on advanced computational models for predicting ASD stability, use of novel polymeric carriers, and methods for successful preparations.

Nondestructive techniques for pharmaceutical drug product characterization

Pharmaceutical product development involves multiple steps; therefore product quality must be assessed to ensure robustness and acceptability. Raw components, production methods, and ambient conditions yield highly variable end products with low batch-to-batch consistency. Although end testing is performed to ensure product quality, intermediate quality checks are limited. Nondestructive techniques like terahertz, near-infrared, X-ray, and Raman spectroscopy are common tools for in-line quality checks and real-time data monitoring. Handheld devices based on these analytical techniques also help in identifying counterfeit drugs products. This review discusses modern regulatory perspectives on the use of nondestructive tools in pharmaceutical quality monitoring.

Application of the Box-Behnken Design in the Development of Amorphous PVP K30-Phosphatidylcholine Dispersions for the Co-Delivery of Curcumin and Hesperetin Prepared by Hot-Melt Extrusion

Background: Curcumin and hesperetin are plant polyphenols known for their poor solubility. To address this limitation, we prepared amorphous PVP K30-phosphatidylcholine dispersions via hot-melt extrusion. Methods: This study aimed to evaluate the effects of the amounts of active ingredients and phosphatidylcholine, as well as the process temperature, on the performance of the dispersions. A Box-Behnken design was employed to assess these factors. Solid-state characterization and biopharmaceutical studies were then conducted. X-ray powder diffraction (XRPD) was used to confirm the amorphous nature of the dispersions, while differential scanning calorimetry (DSC) provided insight into the miscibility of the systems. Fourier-transform infrared spectroscopy (FTIR) was employed to assess the intermolecular interactions. The apparent solubility and dissolution profiles of the systems were studied in phosphate buffer at pH 6.8. In vitro permeability across the gastrointestinal tract and blood-brain barrier was evaluated using the parallel artificial membrane permeability assay. Results: The quantities of polyphenols and phospholipids were identified as significant factors influencing the biopharmaceutical performance of the systems. Solid-state analysis confirmed the formation of amorphous dispersions and the development of interactions among components. Notably, a significant improvement in solubility was observed, with formulations exhibiting distinct release patterns for the active compounds. Furthermore, the in vitro permeability through the gastrointestinal tract and blood-brain barrier was enhanced. Conclusions: The findings suggest that amorphous PVP K30-phosphatidylcholine dispersions have the potential to improve the biopharmaceutical properties of curcumin and hesperetin.

Combining ion-pair strategy and percutaneous permeation enhancers to develop sustained-release paliperidone patch

In this study, a sustained-release paliperidone (PAL) patch was developed using a combination of ion-pair strategy and percutaneous permeation enhancers (PPEs). The ion-pair strategy was used to improve drug-adhesive miscibility and control drug release. PPEs were used to break SC barrier function to facilitate drug skin permeation. The in vitro skin permeation experiments using single-factor experiments and Box-Behnken design gave the optimized formulation, a 55 μm adhesive thickness patch with 7 % (w/w) PAL-LA (Lauric acid), 9.7 % (w/w) Plurol® Oleique CC 497 (POCC). Moreover, the pharmacokinetic study confirmed its potential in sustained-release transdermal patch with longer MRT0-t (18.35 ± 3.11 h) and higher BA (63.14 %) than the gavage group (Cmax = 6.64 ± 2.61 μg/mL, MRT0-t = 2.88 ± 1.06 h, BA = 45.70 %) without significant increasing Cmax. The mechanism study revealed that forming ion-pairs effectively modulated drug's physicochemical properties and doubly ionic H-bond strength to improve drug miscibility in patches. To summarize, a sustained-release patch of PAL was successfully developed, which provided a strategy for sustained-release patches with good drug-polymer miscibility, drug controlled-release, and feasible drug utilization features.

A novel HEMA copolymer hydrogel with antifouling and anti-inflammatory activity as a promising medical device coating layer to prevent microbial adhesion

Compared to antimicrobial agents, anti-adhesive surfaces can reduce bacteria adhesion and biofilm formation in catheters, providing better selectivity, efficiency, and device life span. In this research, novel anionic surface biomaterials were created and tested to reduce microbial adhesion and colonization in medical device coating. Maleic anhydride (MA) was polymerized with 2-HEMA in varying amounts to produce a p(HEMA-co-MA) hydrogel copolymer. Fourier transforms infrared characterization (ATR-FTIR), thermal analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy, swelling capacity, cytotoxicity evaluation, and mixed biofilm formation ability were used to characterize the copolymer hydrogels. Hydrogels were evaluated by considering the guidance and regulations of ISO and ASTM standards. The polymers were dense, had stable cross-linking between both monomers, were non-toxic to the Human Embryonic Kidney (HEK) 293 cell line, and reduced bacterial biofilm formation statistically significantly. Furthermore, increasing the amount of MA affected TGF-1 gene expression, where the gene expression was significantly elevated, especially at the highest percentage of MA. Furthermore, the high percentage of MA in the polymer improved the new polymer's thermal properties, film flexibility, and swelling capacity. These novel polymers could be promising materials for improving catheter biomaterial properties and modifying the surfaces of designated devices to reduce microbial infections and growth.

Advancing the Physicochemical Properties and Therapeutic Potential of Plant Extracts Through Amorphous Solid Dispersion Systems

Plant extracts demonstrate significant potential as a rich source of active pharmaceutical ingredients, exhibiting diverse biological activities and minimal toxicity. However, the low aqueous solubility of extracts and their gastrointestinal permeability, as well as their poor oral bioavailability, limit clinical advancements due to drug delivery problems. An amorphous solid dispersion (ASD) delivers drugs by changing an active pharmaceutical ingredient (API) into an amorphous state to increase the solubility and availability of the API to the body. This research aimed to analyze and summarize the successful advancements of ASD systems derived from plant extracts, emphasizing characterization and the effects on dissolution and pharmacological activity. The results show that ASD systems improve phytoconstituent dissolution, bioavailability, and stability, in addition to reducing dose and toxicity. This research demonstrates the significance of ASD in therapeutic formulations to augment the pharmacological activities and efficacy of medicinal plant extracts. The prospects indicate promising potential for therapeutic applications utilizing ASD systems, alongside medicinal plant extracts for clinical therapy.

Overcoming Challenges in Small-Molecule Drug Bioavailability: A Review of Key Factors and Approaches

The bioavailability of small-molecule drugs remains a critical challenge in pharmaceutical development, significantly impacting therapeutic efficacy and commercial viability. This review synthesizes recent advances in understanding and overcoming bioavailability limitations, focusing on key physicochemical and biological factors influencing drug absorption and distribution. We examine cutting-edge strategies for enhancing bioavailability, including innovative formulation approaches, rational structural modifications, and the application of artificial intelligence in drug design. The integration of nanotechnology, 3D printing, and stimuli-responsive delivery systems are highlighted as promising avenues for improving drug delivery. We discuss the importance of a holistic, multidisciplinary approach to bioavailability optimization, emphasizing early-stage consideration of ADME properties and the need for patient-centric design. This review also explores emerging technologies such as CRISPR-Cas9-mediated personalization and microbiome modulation for tailored bioavailability enhancement. Finally, we outline future research directions, including advanced predictive modeling, overcoming biological barriers, and addressing the challenges of emerging therapeutic modalities. By elucidating the complex interplay of factors affecting bioavailability, this review aims to guide future efforts in developing more effective and accessible small-molecule therapeutics.

Microscope-enabled disc dissolution system: Concordance between drug and polymer dissolution from an amorphous solid dispersion disc and visual disc degradation

A microscopic erosion time test was recently described to anticipate amorphous solid dispersion (ASD) drug load dispersibility limit, using 0.5 ml media volume. Studies here build upon this microscope-enabled method but focus on drug and polymer dissolution from an ASD disc, along with imaging. The objective was 1) to design and build a microscope-enabled disc dissolution system (MeDDiS) with a 900 mL dissolution volume and 2) assess the ability of MeDDiS imaging of dissolving discs to provide concordance with measured drug and polymer dissolution profiles. MeDDiS employed a digital microscope to image ASD discs and a one-liter vessel for dissolution. ASD discs containing ritonavir (5-50 % drug load) and PVPVA were fabricated and subjected to in vitro dissolution using MeDDiS, where disc diameter was quantified with time. Ritonavir and PVPVA release were also measured. Results indicate concordance between imaging and dissolution. Both found 25 % drug load to provide high drug and polymer release, but 30 % yielded low release. Quantitatively, MeDDiS images predicted drug and polymer release profiles, both above and below the drug load cliff. Overall, studies here describe a MeDDiS which has promised to anticipate drug and polymer dissolution, via imaging of dissolving discs, above and below the ASD drug load cliff.

Amorphous solid dispersion to facilitate the delivery of poorly water-soluble drugs: recent advances on novel preparation processes and technology coupling

INTRODUCTION

Amorphous solid dispersion (ASD) technique has recently been used as an effective formulation strategy to significantly improve the bioavailability of insoluble drugs. The main industrialized preparation methods for ASDs are mainly hot melt extrusion and spray drying techniques; however, they face the limitations of being unsuitable for heat-sensitive materials and organic reagent residues, respectively, and therefore novel preparation processes and technology coupling for developing ASDs have received increasing attention.

AREAS COVERED

This paper reviews recent advances in ASD and provides an overview of novel preparation methods, mechanisms for improving drug bioavailability, and especially technology coupling.

EXPERT COVERED

As a mature pharmaceutical technology, ASD has broad application prospects and values. During the period from 2012 to 2024, the FDA has approved 49 formulation products containing ASDs. However, with the diversification of drug types and clinical needs, the traditional formulation technology of ASDs is gradually no longer sufficient to meet the needs of clinical medication. Therefore, this review summarizes the studies on both novel preparation processes and technology combinations; and provides a comprehensive overview of the mechanisms of ASD to improve drug bioavailability, in order to better select appropriate preparation methods for the development of ASD formulations.

Optimizing extrusion processes and understanding conformational changes in itraconazole amorphous solid dispersions using in-line UV-Vis spectroscopy and QbD principles

This paper presents a comprehensive investigation of the manufacturing of itraconazole (ITZ) amorphous solid dispersions (ASDs) with Kolllidon® VA64 (KVA64) using hot-melt extrusion (HME) and in-line process monitoring, employing a Quality by Design (QbD) approach. A sequential Design of Experiments (DoE) strategy was utilized to optimize the manufacturing process, with in-line UV-Vis spectroscopy providing real-time monitoring. The first DoE used a fractional factorial screening design to evaluate critical process parameters (CPPs), revealing that ITZ concentration had the most significant impact on the product quality attributes. The second DoE, employing a central composite design, explored the interactions between feed rate and screw speed, using torque and absorbance at 370 nm as responses to develop a design space. Validation studies confirmed process robustness across multiple days, with stable in-line UV-Vis spectra and consistent product quality using 30 % ITZ, 300 rpm, 150 °C and 7 g/min as the optimized process conditions. Theoretical and experimental analyses indicated that shifts in UV-Vis spectra at different ITZ concentrations were due to conformational changes in ITZ, which were confirmed through density functional theory (DFT) calculations and infrared spectroscopy. This work offers novel insights into the production and monitoring of ITZ-KVA64-ASDs, demonstrating that in-line UV-Vis spectroscopy is a powerful tool for real-time process monitoring and/or control.

Melt-extruded formulations of fenofibrate with various grades of hydrogenated phospholipid exhibit promising in-vitro biopharmaceutical behavior

In the current study, it was demonstrated that three commercially available grades of hydrogenated phospholipids (HPL) differing in their content of phosphatidylcholine may be used as components for hot melt-extruded binary (HPL as sole excipient) or ternary (in combination with copovidone) solid dispersions of fenofibrate (FEN) at mass fractions between 0.5 and 20% (ternary) or 80% (binary). X-ray powder diffraction indicated complete conversion of crystalline fenofibrate into the amorphous state by hot melt extrusion for all ternary blends. In contrast, both the binary blends (HPL- and copovidone-based) contained minor remaining crystallites. Irrespectively, all solid dispersions induced during dissolution studies a supersaturated state of FEN, where the ternary ASDs showed enhanced and more complete release of FEN as compared to the binary blends and, even more pronounced, in comparison to the marketed micronized and nano-milled formulations. In terms of the cumulated amount permeated, there were marginal differences between the various formulations when combined dissolution/permeation was done using FeSSIF as donor medium; with FaSSIF as donor medium, the binary HPL-ASD containing the grade with the highest phosphatidylcholine fraction performed best in terms of permeation, even significantly better than the marketed nano-crystal formulation. Otherwise, no significant differences were seen between the various grades of HPL when FEN dissolution and permeation were analyzed for ternary solid dispersions. In conclusion, the in-vitro biopharmaceutical behaviour of hydrogenated phospholipid-containing blends manufactured by hot melt extrusion appears promising. They can be a viable formulation option for poorly water-soluble and lipophilic drug compounds like FEN.

Mechanochemical comparison of ball milling processes for levofloxacin amorphous polymeric systems

This study aimed to investigate the amorphization capabilities of levofloxacin hemihydrate (LVXh), a fluoroquinolone drug, using a polymer excipient, Eudragit® L100 (EL100). Ball milling (BMing) was chosen as the manufacturing process and multiple mill types were utilized for comparison purposes. The product outcomes of each mill were analyzed in detail. The solid-state of the samples produced was comprehensively characterized by Powder X-ray Diffraction (PXRD), In-situ PXRD, Differential Scanning Calorimetry (DSC), Solid-State Fourier Transform Infrared Spectroscopy (FT-IR), and Dynamic Vapor Sorption (DVS). The crystallographic planes of LVXh were investigated by in-situ PXRD to disclose the presence or absence of weak crystallographic plane(s). The mechanism of LVXh:EL100 system formation was discovered as a two-step process, first involving amorphization of LVXh followed by an interaction with EL100, rather than as an instantaneous process. DVS studies of LVXh:EL100 samples showed different stability properties depending on the mill used and % LVXh present. Overall, a more sustainable approach for achieving full amorphization of the fluoroquinolone drug, LVXh, was accomplished, and advancements to the fast-growing world of pharmaceutical mechano- and tribo-chemistry were made.

A Study on the Stability of High Drug Solubility Characteristics of Hydroxyphenyl Adhesives under the Interference of CPEs

Novel hydroxyphenyl adhesives (HP-PSAs) could significantly increase drug solubility and control drug release through a doubly ionic hydrogen bond (DIH bond) in the patch. However, chemical penetration enhancers (CPEs) always destroy the performance of most adhesives. As a result, this work investigated the stability of both the HP-PSA features and the DIH bond under the interference of the CPEs. Donepezil (DON) was chosen as the model drug, and CPEs with hydroxyl, carboxyl, amido, and ester groups were selected as model CPEs. Unlike the commonly used neutral H-bond, the DIH bond between DON and the HP-PSA was still stable under the interference of the CPEs, resulting in the 2-3-fold drug solubility in the HP-PSA, which was higher than that in the nonfunctional PSA, which reduced the drug crystallization risk and the difficulty of formulation design. FT-IR, 1H NMR, XPS, dynamic simulation, and molecular docking revealed the mechanism of the stability feature of both the DIH bond and the high drug solubility of the HP-PSA, which was that the formed neutral H-bond interaction caused by CPEs is weaker than that of the DIH bond between DON and the HP-PSA. Furthermore, the drug release, skin permeation, and CPE release study showed that the newly formed weak H-bond and strong ionic H-bond interaction promoted or controlled both DON and CPE release, respectively, thereby influencing drug skin permeation, which provided a theoretical basis for drug release regulation. To summarize, besides the reversible, strong features of the DIH bond in our previous study, the stability of the interaction made the HP-PSA's high drug solubility potential to be applied in the TDDS.

Solubilization techniques used for poorly water-soluble drugs

About 40% of approved drugs and nearly 90% of drug candidates are poorly water-soluble drugs. Low solubility reduces the drugability. Effectively improving the solubility and bioavailability of poorly water-soluble drugs is a critical issue that needs to be urgently addressed in drug development and application. This review briefly introduces the conventional solubilization techniques such as solubilizers, hydrotropes, cosolvents, prodrugs, salt modification, micronization, cyclodextrin inclusion, solid dispersions, and details the crystallization strategies, ionic liquids, and polymer-based, lipid-based, and inorganic-based carriers in improving solubility and bioavailability. Some of the most commonly used approved carrier materials for solubilization techniques are presented. Several approved poorly water-soluble drugs using solubilization techniques are summarized. Furthermore, this review summarizes the solubilization mechanism of each solubilization technique, reviews the latest research advances and challenges, and evaluates the potential for clinical translation. This review could guide the selection of a solubilization approach, dosage form, and administration route for poorly water-soluble drugs. Moreover, we discuss several promising solubilization techniques attracting increasing attention worldwide.

Encapsulation of astaxanthin in OSA-starch based amorphous solid dispersions with HPMCAS-HF/Soluplus® as effective recrystallization inhibitor

In this study, the interaction among multifunctional excipients, including polysaccharides, cellulose derivatives, and surfactants, was particularly investigated, together with its impact on the physicochemical properties of astaxanthin amorphous solid dispersions (ASTX ASDs). It was indicated that Span 20 could rapidly form hemimicelles or aggregates in the presence of hypromellose acetate succinate HF (HPMCAS-HF, HF) or Soluplus®, while octenyl succinic anhydride modified starch (OSA-starch) efficiently assisted in the coalescence inhibition of drug-excipients aggregates, which was jointly beneficial to the recrystallization inhibition of amorphous ASTX. ASTX ASDs were further prepared with OSA-starch, HPMCAS-HF/Soluplus®, and Span 20 as the wall materials. DSC, SEM, and XRD confirmed that crystalline ASTX had transformed to amorphous state in the ASDs, while FT-IR spectra provided evidence suggesting the existence of hydrogen bonds and hydrophobic interaction between ASTX and the excipients. The dissolution of ASTX ASDs in different media revealed significant promotion, while the pharmacokinetic results further demonstrated the oral bioavailability of ASTX ASDs enhanced remarkably, exhibiting 2.75-fold (SD1) and 1.87-fold (SD2) increase, respectively, compared to ASTX bulk powder. In summary, the cellulose derivatives-surfactant interaction had great impact on the physicochemical properties of ASTX ASDs, and their combinations exhibited great potential for delivering the hydrophobic bioactive compounds efficiently.

Pharmaceutical approaches for enhancing solubility and oral bioavailability of poorly soluble drugs

High solubility in water and physiological fluids is an indispensable requirement for the pharmacological efficacy of an active pharmaceutical ingredient. Indeed, it is well established that pharmaceutical substances exhibiting limited solubility in water are inclined towards diminished and inconsistent absorption following oral administration, consequently resulting in variability in therapeutic outcomes. The current advancements in combinatorial chemistry and pharmaceutical design have facilitated the creation of drug candidates characterized by increased lipophilicity, elevated molecular size, and reduced aqueous solubility. Undoubtedly, the issue of poorly water-soluble medications has been progressively escalating over recent years. Indeed, 40% of the top 200 oral medications marketed in the United States, 33% of drugs listed in the US pharmacopoeia, 75% of compounds under development and 90% of new chemical entities are insufficiently water-soluble compounds. In order to address this obstacle, formulation scientists employ a variety of approaches, encompassing both physical and chemical methods such as prodrug synthesis, salt formation, solid dispersions formation, hydrotropic substances utilization, solubilizing agents incorporation, cosolvent addition, polymorphism exploration, cocrystal creation, cyclodextrins complexation, lipid formulations, particle size reduction and nanoformulation techniques. Despite the utilization of these diverse approaches, the primary reason for the failure in new drug development persists as the poor aqueous solubility of pharmaceutical compounds. This paper, therefore, delves into the foundational principles that underpin the implementation of various formulation strategies, along with a discussion on the respective advantages and drawbacks associated with each approach. Additionally, a discourse is provided regarding methodological frameworks for making informed decisions on selecting an appropriate formulation strategy to effectively tackle the key challenges posed during the development of a poorly water-soluble drug candidate.

The comparison of melt technologies based on mesoporous carriers for improved carvedilol dissolution

High-shear (HS) melt granulation and hot melt extrusion (HME) were compared as perspective melt-based technologies for preparation of amorphous solid dispersions (ASDs). ASDs were prepared using mesoporous carriers (SyloidⓇ 244FP or NeusilinⓇ US2), which were loaded with carvedilol dispersed in polymeric matrix (polyethylene glycol 6000 or SoluplusⓇ). Formulations with high carvedilol content were obtained either by HME (11 extrudates with polymer:carrier ratio 1:1) or HS granulation (6 granulates with polymer:carrier ratio 3:1). DSC and XRD analysis confirmed the absence of crystalline carvedilol for the majority of prepared ADSs, thus confirming the stabilizing effect of selected polymers and carriers over amorphous carvedilol. HME produced larger particles compared to HS melt granulation, which was in line with better flow time and Carr index of extrudates. Moreover, SEM images revealed smoother surface of ASDs obtained by HME, contributing to less obstructed flow. The rougher and more porous surface of HS granules was correlated to larger granule specific surface area, manifesting in faster carvedilol release from SyloidⓇ 244FP-based granules, as compared to their HME counterparts. Regarding dissolution, the two HS-formulations performed superior to pure crystalline carvedilol, thereby confirming the suitability of HS melt granulation for developing dosage forms with improved carvedilol dissolution.

Improved Dissolution Time and Oral Bioavailability of Pioglitazone Using Liquisolid Tablets: Formulation, In Vitro Characterization, and In Vivo Pharmacokinetics in Rabbits

In the current study, it was intended to prepare liquisolid tablets of pioglitazone HCl to improve the bioavailability and dissolution time of the drug, as it has low solubility in water. Mathematical formulas were adopted, and the quantities of the carrier (MCC), coating material (colloidal silicon dioxides), and nonvolatile liquid vehicle (Tween 80) were taken. Various ratios of the drug to liquid and carrier to coating had been used in the formulation of liquisolid compacts. The evaluation of the formulated liquisolid compacts was done by performing FTIR, DSC, XRD, and SEM studies. Postcompression parameters, dissolution, stability, and bioavailability were accessed for the optimized formulation. FTIR and DSC studies showed the compatibility of the drugs and excipients. XRD revealed the transition to the amorphous state. It was found that the properties of the newly manufactured liquisolid tablets were within the parameters of what is considered acceptable. The optimized formulation of LST10 showed 99.87 ± 0.19% (p < 0.05) pioglitazone released within 60 min of dissolution. Dissolution data treatments (Q 15, IDR, RDR, %DE, MDT, f 1, and f 2) resulted in better drug release than other drugs studied and marketed tablet formulations. The optimized formulation produced had been proven stable when it was subjected to accelerated stability testing. This suggested that the bioavailability of pioglitazone was enhanced, as indicated by the substantial increase in AUC0-t (3.06-fold) and C max (4.18-fold). According to the findings, the selected combination and method significantly increased the dissolution time and bioavailability of pioglitazone. Moreover, this developed method can be used for other drugs with low water solubility.

Amorphous Solid Dispersion Formation for Enhanced Release Performance of Racemic and Enantiopure Praziquantel

Praziquantel (PZQ) is the treatment of choice for schistosomiasis, which affects more than 250 million people globally. Commercial tablets contain the crystalline racemic compound (RS-PZQ) which limits drug dissolution and oral bioavailability and can lead to unwanted side effects and poor patient compliance due to the presence of the S-enantiomer. While many approaches have been explored for improving PZQ's dissolution and oral bioavailability, studies focusing on investigating its release from amorphous solid dispersions (ASDs) have been limited. In this work, nucleation induction time experiments were performed to identify suitable polymers for preparing ASDs using RS-PZQ and R-PZQ, the therapeutically active enantiomer. Cellulose-based polymers, hydroxypropyl methylcellulose acetate succinate (HPMCAS, MF grade) and hydroxypropyl methylcellulose (HPMC, E5 LV grade), were the best crystallization inhibitors for RS-PZQ in aqueous media and were selected for ASD preparation using solvent evaporation (SE) and hot-melt extrusion (HME). ASDs prepared experimentally were subjected to X-ray powder diffraction to verify their amorphous nature and a selected number of ASDs were monitored and found to remain physically stable following several months of storage under accelerated-stability testing conditions. SE HPMCAS-MF ASDs of RS-PZQ and R-PZQ showed faster release than HPMC E5 LV ASDs and maintained good performance with an increase in drug loading (DL). HME ASDs of RS-PZQ formulated using HPMCAS-MF exhibited slightly enhanced release compared to that of SE ASDs. SE HPMCAS-MF ASDs showed a maximum release increase of the order of 6 times compared to generic and branded (Biltricide) PZQ tablets. More importantly, SE R-PZQ ASDs with HPMCAS-MF released the drug as effectively as RS-PZQ or better, depending on the DL used. These findings have significant implications for the development of commercial PZQ formulations comprised solely of the R-enantiomer, which can result in mitigation of the biopharmaceutical and compliance issues associated with current commercial tablets.

Polymers Enhance Chlortetracycline Hydrochloride Solubility

Chlortetracycline hydrochloride (CTC) is a broad-spectrum tetracycline antibiotic with a wide range of antibacterial activities. Due to low solubility, poor stability, and low bioavailability, clinical preparation development is limited. We sought to improve these solubility and dissolution rates by preparing solid dispersions. A hydrophilic polymer was selected as the carrier, and a solid dispersion was prepared using a medium grinding method, with samples characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), and particle size distribution (PSD). To maximize CTC solubility and stability, different polymer types and optimal drug-to-polymer ratios were screened. The solubility of optimized povidone K30 (PVPK30) (1/0.75, w/w)-, hydroxypropyl-β-cyclodextrin (HP-β-CD) (1/2, w/w)-, and gelatin (1/1, w/w)-based solid dispersions was 6.25-, 7.7-, and 3.75-fold higher than that of pure CTC powder, respectively. Additionally, in vitro dissolution studies showed that the gelatin-based solid dispersion had a higher initial dissolution rate. SEM and PS analyses confirmed that this dispersion had smaller and more uniform particles than PVPK30 and HP-β-CD dispersions. Therefore, successful solid polymer dispersion preparations improved the CTC solubility, dissolution rates, and stability, which may have potential as drug delivery systems.

Synthesis and characterization of fullerene-based nanocarrier for targeted delivery of quercetin to the brain

Aim: Preparation of quercetin fullerene conjugate (QFC) for nose-to-brain delivery and their in vitro and ex vivo characterizations.Methods: Carboxylated fullerene was converted into acetylated fullerene and quercetin was conjugated and physically adsorbed on acetylated fullerene.Results: The particle size and zeta potential of QFC and chitosan-coated QFC (CC-QFC) were found to be 179.2 ± 1.10, 293.4 ± 2.757, -5.28 ± 1.43 and 11.6 ± 0.4 respectively. The entrapment efficiency, loading efficiency of QFC were found to be 85.55% and 42.77%. The MTT assay revealed 80.69% SH-SY5Y cell viability at a concentration of 50 μg/ml. CC-QFC showed remarkable (89.20%) ex vivo mucoadhesive properties compared with QFC (66.67%). Further study showed no significant ciliotoxicity by CC-QFC.Conclusion: The obtained results suggested the potential of CC-QFC for treatment in Alzheimer's disease.

Oral Bioavailability Enhancement of Poorly Soluble Drug by Amorphous Solid Dispersion Using Sucrose Acetate Isobutyrate

The focus of the present work was to develop amorphous solid dispersion (ASD) formulation of aprepitant (APT) using sucrose acetate isobutyrate (SAIB) excipient, evaluate for physicochemical attributes, stability, and bioavailability, and compared with hydroxypropyl methylcellulose (HPMC) based formulation. Various formulations of APT were prepared by solvent evaporation method and characterized for physiochemical and in-vivo performance attributes such as dissolution, drug phase, stability, and bioavailability. X-ray powder diffraction indicated crystalline drug conversion into amorphous phase. Dissolution varied as a function of drug:SAIB:excipient proportion. The dissolution was more than 80% in the optimized formulation (F10) and comparable to HPMC based formulation (F13). Stability of F10 and F13 formulations stored at 25 C/60% and 40°C/75% RH for three months were comparable. Both ASD formulations (F10 and F13) were bioequivalent as indicated by the pharmacokinetic parameters Cmax and AUC0-∞. Cmax and AUC0-∞ of F10 and F13 formulations were 2.52 ± 0.39, and 2.74 ± 0.32 μg/ml, and 26.59 ± 0.39, and 24.79 ± 6.02 μg/ml.h, respectively. Furthermore, the bioavailability of ASD formulation was more than twofold of the formulation containing crystalline phase of the drug. In conclusion, stability and oral bioavailability of SAIB based ASD formulation is comparable to HPMC-based formulation of poorly soluble drugs.

Co-crystallization of Hesperidin with different co-formers to enhance solubility, antioxidant and anti-inflammatory activities

Hesperidin (HSP) is a natural flavonoid glycoside with very low aqueous solubility and a slow dissolution rate, limiting its effectiveness. This study aims to address these issues by creating co-crystals of hesperidin with water-soluble small molecules (co-formers) such as L-arginine, glutathione, glycine, and nicotinamide. Using the solvent drop grinding method, we prepared three different molar ratios of hesperidin to co-formers (1:1, 1:3, and 1:5) and conducted in-vitro solubility and dissolution studies. The results demonstrated that the prepared co-crystals exhibited significantly enhanced solubility and dissolution rates compared to untreated hesperidin. Of particular note, the HSP co-crystals formula (HSP: L-arg 1:5) displayed approximately 4.5 times higher dissolution than pure hesperidin. Further analysis using FTIR, powder x-ray diffraction patterns, and DSC thermograms validated the formation of co-crystals between HSP and L-arginine. Additionally, co-crystallization with L-arginine improved the in vitro anti-inflammatory and antioxidant activities of hesperidin compared to the untreated drug. This study highlights the potential of using water-soluble small molecules (co-formers) through co-crystallization to enhance the solubility, dissolution, and biological activities of poorly water-soluble drugs. Furthermore, in vivo studies are crucial to validate these promising results.

Specific intermolecular interaction with sodium glycocholate generates the co-amorphous system showing higher physical stability and aqueous solubility of Y5 receptor antagonist of neuropeptide Y, a brick dust molecule

Drugs with poor water and lipid solubility are termed "brick dust." We previously successfully developed a co-amorphous system of a novel neuropeptide Y5 receptor antagonist (AntiY5R), a brick dust molecule, using sodium taurocholate (NaTC) as a co-former. However, the maximum improvement in AntiY5R dissolution by the co-amorphous system was only approximately 10 times greater than that of the crystals. Therefore, in the current study, other bile salts, including sodium cholate (NaC), sodium chenodeoxycholate (NaCC), and sodium glycocholate (NaGC), were examined as co-formers to further improve AntiY5R dissolution. NaC, NaCC, and NaGC have glass transition temperatures above 150°C. All three co-amorphous systems prepared successfully retained the amorphous form of AntiY5R for 3 months at 40°C, but the co-amorphous system with NaGC (AntiY5R-NaGC; 1:9 molar ratio) provided the highest improvement in AntiY5R dissolution, which was approximately 50 times greater than that of the crystals. Possible intermolecular interactions via the glycine moiety of NaGC more than the other bile salts would contribute to the highest dissolution enhancement with AntiY5R-NaGC. Thus, NaGC would be a promising co-former for formulating stable co-amorphous systems to enhance the dissolution behavior of brick dust molecules.

Preparation, Characterization and Evaluation of Nintedanib Amorphous Solid Dispersions with Enhanced Oral Bioavailability

The dissolution and bioavailability challenges posed by poorly water-soluble drugs continue to drive innovation in pharmaceutical formulation design. Nintedanib (NDNB) is a typical BCS class II drug that has been utilized to treat idiopathic pulmonary fibrosis (IPF). Due to the low solubility, its oral bioavailability is relatively low, limiting its therapeutical effectiveness. It is crucial to enhance the dissolution and the oral bioavailability of NDNB. In this study, we focused on the preparation of amorphous solid dispersions (ASD) using hot melt extrusion (HME). The formulation employed Kollidon® VA64 (VA64) as the polymer matrix, blended with the NDNB at a ratio of 9:1. HME was conducted at temperatures ranging from 80 °C to 220 °C. The successful preparation of ASD was confirmed through various tests including polarized light microscopy (PLM), X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). The in-vitro cumulative release of NDNB-ASD in 2 h in a pH 6.8 medium was 8.3-fold higher than that of NDNB (p < 0.0001). In a pH 7.4 medium, it was 10 times higher (p < 0.0001). In the in-vivo pharmacokinetic experiments, the area under curve (AUC) of NDNB-ASD was 5.3-fold higher than that of NDNB and 2.2 times higher than that of commercially available soft capsules (Ofev®) (p < 0.0001). There was no recrystallization after 6 months under accelarated storage test. Our study indicated that NDNB-ASD can enhance the absorption of NDNB, thus providing a promising method to improve NDNB bioavailability in oral dosages.

Solid Dispersions Obtained by Ball Milling as Delivery Platform of Etodolac, a Model Poorly Soluble Drug

Poor water solubility of drugs is a limiting factor for their bioavailability and pharmacological activity. Many approaches are known to improve drug solubility, and among them, the physical method, solid dispersions (SDs), is applied. SDs are physical mixtures of a drug and a carrier, sometimes with the addition of a surfactant, which can be obtained by milling, cryomilling, spray-drying, or lyophilization processes. In this study, solid dispersions with etodolac (ETD-SDs) were prepared by the milling method using different carriers, such as hypromellose, polyvinylpyrrolidone, copovidone, urea, and mannitol. Solubility studies, dissolution tests, morphological assessment, thermal analysis, and FTIR imaging were applied to evaluate the SD properties. It was shown that the ball-milling process can be applied to obtain SDs with ETD. All designed ETD-SDs were characterized by higher water solubility and a faster dissolution rate compared to unprocessed ETD. SDs with amorphous carriers (HPMC, PVP, and PVP/VA) provided greater ETD solubility than dispersions with crystalline features (urea and mannitol). FTIR spectra confirmed the compatibility of ETD with tested carriers.

Amorphous Polymer-Phospholipid Solid Dispersions for the Co-Delivery of Curcumin and Piperine Prepared via Hot-Melt Extrusion

Curcumin and piperine are plant compounds known for their health-promoting properties, but their use in the prevention or treatment of various diseases is limited by their poor solubility. To overcome this drawback, the curcumin-piperine amorphous polymer-phospholipid dispersions were prepared by hot melt extrusion technology. X-ray powder diffraction indicated the formation of amorphous systems. Differential scanning calorimetry confirmed amorphization and provided information on the good miscibility of the active compound-polymer-phospholipid dispersions. Owing to Fourier-transform infrared spectroscopy, the intermolecular interactions in systems were investigated. In the biopharmaceutical properties assessment, the improvement in solubility as well as the maintenance of the supersaturation state were confirmed. Moreover, PAMPA models simulating the gastrointestinal tract and blood-brain barrier showed enhanced permeability of active compounds presented in dispersions compared to the crystalline form of individual compounds. The presented paper suggests that polymer-phospholipid dispersions advantageously impact the bioaccessibility of poorly soluble active compounds.

Investigation of Stabilized Amorphous Solid Dispersions to Improve Oral Olaparib Absorption

In this study, we investigated the formulation of stable solid dispersions to enhance the bioavailability of olaparib (OLA), a therapeutic agent for ovarian cancer and breast cancer characterized as a BCS class IV drug with low solubility and low permeability. Various polymers were screened based on solubility tests, and OLA-loaded solid dispersions were prepared using spray drying. The physicochemical properties of these dispersions were investigated via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier Transform Infrared Spectroscopy (FT-IR). Subsequent dissolution tests, along with assessments of morphological and crystallinity changes in aqueous solutions, led to the selection of a hypromellose (HPMC)-based OLA solid dispersion as the optimal formulation. HPMC was effective at maintaining the supersaturation of OLA in aqueous solutions and exhibited a stable amorphous state without recrystallization. In an in vivo study, this HPMC-based OLA solid dispersion significantly enhanced bioavailability, increasing AUC0-24 by 4.19-fold and Cmax by more than 10.68-fold compared to OLA drug powder (crystalline OLA). Our results highlight the effectiveness of HPMC-based solid dispersions in enhancing the oral bioavailability of OLA and suggest that they could be an effective tool for the development of oral drug formulations.

Generality of Enhancing the Dissolution Rates of Free Acid Amorphous Solid Dispersions by the Incorporation of Sodium Hydroxide

The incorporation of a counterion into an amorphous solid dispersion (ASD) has been proven to be an attractive strategy to improve the drug dissolution rate. In this work, the generality of enhancing the dissolution rates of free acid ASDs by incorporating sodium hydroxide (NaOH) was studied by surface-area-normalized dissolution. A set of diverse drug molecules, two common polymer carriers (copovidone or PVPVA and hydroxypropyl methylcellulose acetate succinate or HPMCAS), and two sample preparation methods (rotary evaporation and spray drying) were investigated. When PVPVA was used as the polymer carrier for the drugs in this study, enhancements of dissolution rates from 7 to 78 times were observed by the incorporation of NaOH into the ASDs at a 1:1 molar ratio with respect to the drug. The drugs having lower amorphous solubilities showed greater enhancement ratios, providing a promising path to improve the drug release performance from their ASDs. Samples generated by rotary evaporation and spray drying demonstrated comparable dissolution rates and enhancements when NaOH was added, establishing a theoretical foundation to bridge the ASD dissolution performance for samples prepared by different solvent-removal processes. In the comparison of polymer carriers, when HPMCAS was applied in the selected system (indomethacin ASD), a dissolution rate enhancement of 2.7 times by the incorporated NaOH was observed, significantly lower than the enhancement of 53 times from the PVPVA-based ASD. This was attributed to the combination of a lower dissolution rate of HPMCAS and the competition for NaOH between IMC and HPMCAS. By studying the generality of enhancing ASD dissolution rates by the incorporation of counterions, this study provides valuable insights into further improving drug release from ASD formulations of poorly water-soluble drugs.

QbD-Based Development and Evaluation of Pazopanib Hydrochloride Extrudates Prepared by Hot-Melt Extrusion Technique: In Vitro and In Vivo Evaluation

BACKGROUND

Pazopanib hydrochloride (PZB) is a protein kinase inhibitor approved by the United States Food and Drug Administration and European agencies for the treatment of renal cell carcinoma and other renal malignancies. However, it exhibits poor aqueous solubility and inconsistent oral drug absorption. In this regard, the current research work entails the development and evaluation of the extrudates of pazopanib hydrochloride by the hot-melt extrusion (HME) technique for solubility enhancement and augmenting oral bioavailability.

RESULTS

Solid dispersion of the drug was prepared using polymers such as Kollidon VA64, hydroxypropylmethylcellulose (HPMC), Eudragit EPO, and Affinisol 15LV in a 1:2 ratio by the HME process through a lab-scale 18 mm extruder. Systematic optimization of the formulation variables was carried out with the help of custom screening design (JMP Software by SAS, Version 14.0) to study the impact of polymer type and plasticizer level on the quality of extrudate processability by measuring the torque value, appearance, and disintegration time as the responses. The polymer blends containing Kollidon VA64 and Affinisol 15LV resulted in respective clear transparent extrudates, while Eudragit EPO and HPMC extrudates were found to be opaque white and brownish, respectively. Furthermore, evaluation of the impact of process parameters such as screw rpm and barrel temperature was measured using a definitive screening design on the extrude appearance, torque, disintegration time, and dissolution profile. Based on the statistical outcomes, it can be concluded that barrel temperature has a significant impact on torque, disintegration time, and dissolution at 30 min, while screw speed has an insignificant impact on the response variables. Affinisol extrudates showed less moisture uptake and faster dissolution in comparison to Kollidon VA64 extrudates. Affinisol extrudates were evaluated for polymorphic stability up to a 3-month accelerated condition and found no recrystallization. PZB-Extrudates using the Affinisol polymer (Test formulation A) revealed significantly higher bioavailability (AUC) in comparison to the free Pazopanib drug and marketed formulation.

Colyophilized Sugar-Polymer Dispersions for Enhanced Processing and Storage Stability

Sucrose and trehalose pharmaceutical excipients are employed to stabilize protein therapeutics in a dried state. The mechanism of therapeutic protein stabilization is dependent on the sugars being present in an amorphous solid-state. Colyophilization of sugars with high glass transition polymers, polyvinylpyrrolidone (PVP), and poly(vinylpyrrolidone vinyl acetate) (PVPVA), enhances amorphous sugar stability. This study investigates the stability of colyophilized sugar-polymer systems in the frozen solution state, dried state postlyophilization, and upon exposure to elevated humidity. Binary systems of sucrose or trehalose with PVP or PVPVA were lyophilized with sugar/polymer ratios ranging from 2:8 to 8:2. Frozen sugar-PVPVA solutions exhibited a higher glass transition temperature of the maximally freeze-concentrated amorphous phase (Tg') compared to sugar-PVP solutions, despite the glass transition temperature (Tg) of PVPVA being lower than PVP. Tg values of all colyophilized systems were in a similar temperature range irrespective of polymer type. Greater hydrogen bonding between sugars and PVP and the lower hygroscopicity of PVPVA influenced polymer antiplasticization effects and the plasticization effects of residual water. Plasticization due to water sorption was investigated in a dynamic vapor sorption humidity ramping experiment. Lyophilized sucrose systems exhibited increased amorphous stability compared to trehalose upon exposure to the humidity. Recrystallization of trehalose was observed and stabilized by polymer addition. Lower concentrations of PVP inhibited trehalose recrystallization compared to PVPVA. These stabilizing effects were attributed to the increased hydrogen bonding between trehalose and PVP compared to trehalose and PVPVA. Overall, the study demonstrated how differences in polymer hygroscopicity and hydrogen bonding with sugars influence the stability of colyophilized amorphous dispersions. These insights into excipient solid-state stability are relevant to the development of stabilized biopharmaceutical solid-state formulations.

A Low Transition Temperature Mixture-based viscosupplementation complemented with celecoxib for osteoarthritis treatment

Viscosupplementation consists of hyaluronic acid (HA) intra-articular injections, commonly applied for osteoarthritis treatment while non-steroidal anti-inflammatory drugs (NSAIDs) are widely administered for pain relief. Here, HA and a NSAID (celecoxib) were combined in a formulation based on a low transition temperature mixture (LTTM) of glycerol:sorbitol, reported to increase celecoxib's solubility, thus rendering a potential alternative viscosupplement envisioning enhanced therapeutic efficiency. The inclusion of glucosamine, a cartilage precursor, was also studied. The developed formulations were assessed in terms of rheological properties, crucial for viscosupplementation: the parameters of crossover frequency, storage (G') and loss (G'') moduli, zero-shear-rate viscosity, stable viscosity across temperatures, and shear thinning behaviour, support viscoelastic properties suitable for viscosupplementation. Additionally, the gels biocompatibility was confirmed in chondrogenic cells (ATDC5). Regarding drug release studies, high and low clearance scenarios demonstrated an increased celecoxib (CEX) release from the gel (6 to 73-fold), compared to dissolution in PBS. The low clearance setup presented the highest and most sustained CEX release, highlighting the importance of the gel structure in CEX delivery. NMR stability studies over time demonstrated the LTTM+HA+CEX (GHA+CEX) gel as viable candidate for further in vivo evaluation. In sum, the features of GHA+CEX support its potential use as alternative viscosupplement.

Assessing and mitigating pH-mediated DDI risks in drug development - formulation approaches and clinical considerations

pH-mediated drug-drug interactions (DDI) is a prevalent DDI in drug development, especially for weak base compounds with highly pH-dependent solubility. FDA has released a guidance on the evaluation of pH-mediated DDI assessments using in vitro testing and clinical studies. Currently, there is no common practice of ways of testing across the academia and industry. The development of biopredictive method and physiologically-based biopharmaceutics modeling (PBBM) approaches to assess acid-reducing agent (ARA)-DDI have been proven with accurate prediction and could decrease drug development burden, inform clinical design and potentially waive clinical studies. Formulation strategies and careful clinical design could help mitigate the pH-mediated DDI to avoid more clinical studies and label restrictions, ultimately benefiting the patient. In this review paper, a detailed introduction on biorelevant dissolution testing, preclinical and clinical study requirement and PBPK modeling approaches to assess ARA-DDI are described. An improved decision tree for pH-mediated DDI is proposed. Potential mitigations including clinical or formulation strategies are discussed.

A novel Posaconazole oral formulation using spray dried solid dispersion technology: in-vitro and in-vivo study

SD (solid dispersion) technology is one of the well-recognized solubility enhancement methods; but the use of versatile carriers in ASD (amorphous SD) to achieve the added advantage of modified release along with solubility improvement is an emerging area of exploration. Spray drying is a widely used technology with excellent scalability and product attributes. The SD carriers explored were Soluplus®, possessing excellent solubilization properties that may enhance bioavailability and is suitable for innovative processing, and Gelucire 43/01, a lipid polymer utilized in a non-effervescent-based floating gastro-retentive DDS for the modified release of API. The CPPs of spray drying were screened during preliminary trials, and the formulation variables were optimized using a 32 Full Factorial Design. All nine batches were evaluated for % yield, % drug content, flow properties, floating behavior, saturation solubility, and in-vitro drug release in 0.1 N HCl. The optimized batch characterized based on DSC (differential scanning calorimetry) and PXRD (powder X-ray diffraction) confirmed the amorphous nature of entrapped drug in SDD (spray-dried dispersion). Particle size analysis and SEM (scanning electron microscopy) demonstrated micron size irregular shaped particles. Residual solvent analysis by GCMS-HS confirmed the elimination of organic solvents from SDD. The optimized batch was found stable after 6 months stability study as per ICH guidelines. In-vivo roentgenography study in New Zealand white rabbit showed the residence of SDD in gastric environment for sufficient time. The pharmacokinetic study was performed in male Sprague-Dawley rats to determine the bioavailability of developed SDD based product in fasting and fed conditions, and to compare the data with marketed Noxafil formulation. The current research is focused on the development of a novel ternary SDD (spray-dried dispersion)-based gastro-retentive formulation for an anti-fungal drug Posaconazole.

The challenge of downstream processing of spray dried amorphous solid dispersions into minitablets designed for the paediatric population - A sustainable product development approach

Poorly water-soluble drugs present a significant challenge in the development of oral solid dosage forms (OSDs). In formulation development the appropriate use of excipients to adjust solubility, and the choice of manufacturing method and pharmaceutical processes to obtain a dosage form to meet the needs of the patient group, is crucial. Preparing an amorphous solid dispersion (ASD) is a well-established method for solubility enhancement, and spray drying (SD) a common manufacturing method. However, the poor flowability of spray dried materials poses a significant challenge for downstream processing. Promoting sustainability in OSD development involves embracing a versatile formulation design, which enables a broader spectrum of patients to use the product, as opposed to altering existing dosage forms retrospectively. The objective of the current study was to develop a formulation of spray dried indomethacin ASD suited to the production, by direct compression, of instant release paediatric minitablets. Excipients evaluated were PVP or HPMCAS in solid dispersions at the preformulation phase, and MCC and lactose as a filler in direct compression. From the studied formulations, a 3:1 ratio blend of Vivapur 200/Pharmatose 200 M (MCC/lactose) with 0.5% (w/w) magnesium stearate was found to be the most promising in tableting, and minitablets containing a 6.22% content of spray-dried ASD of indomethacin/PVP K 29-32 could be obtained with desired tablet hardness and pharmaceutical quality, complying with tests of weight variation and fast disintegration in an aqueous environment. As a case example, this study provides a good foundation for further studies in harnessing a sustainable approach to the development of pharmaceutical formulations that can appropriately serve different patient sub-populations.