Manufacturing of solid dispersions of poorly water soluble drugs by spray drying: Formulation and process considerations

Developing HME-Based Drug Products Using Emerging Science: a Fast-Track Roadmap from Concept to Clinical Batch

This paper presents a rational workflow for developing enabling formulations, such as amorphous solid dispersions, via hot-melt extrusion in less than a year. First, our approach to an integrated product and process development framework is described, including state-of-the-art theoretical concepts, modeling, and experimental characterization described in the literature and developed by us. Next, lab-scale extruder setups are designed (processing conditions and screw design) based on a rational, model-based framework that takes into account the thermal load required, the mixing capabilities, and the thermo-mechanical degradation. The predicted optimal process setup can be validated quickly in the pilot plant. Lastly, a transfer of the process to any GMP-certified manufacturing site can be performed in silico for any extruder based on our validated computational framework. In summary, the proposed workflow massively reduces the risk in product and process development and shortens the drug-to-market time for enabling formulations.

Microencapsulation of luteinizing hormone-releasing hormone agonist in poly (lactic-co-glycolic acid) microspheres by spray-drying

A spray drying technique was developed to prepare injectable and biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres encapsulating a model luteinizing hormone-releasing hormone agonist (LHRHa)-based peptide, leuprolide. Various spray drying parameters were evaluated to prepare 1-month controlled release formulations with a similar composition to the commercial Lupron Depot® (LD). A single water-in-oil emulsion of aqueous leuprolide/gelatin solution in PLGA 75/25 acid capped (13 kDa Mw) dissolved in methylene chloride (DCM) was spray-dried before washing the microspheres in cold ddH2O and freeze-drying. The spray-drying microencapsulation was characterized by: particle size/distribution (span), morphology, drug/gelatin loading, encapsulation efficiency, and residual DCM and water content. Long-term release was tested over 9 weeks in PBS + 0.02% Tween 80 + 0.02% sodium azide pH 7.4 (PBST) at 37 °C. Several physical-chemical parameters were monitored simultaneously for selected formulations, including: water uptake, mass loss, dry and hydrated glass transition temperature, to help understand the related long-term release profiles and explore the underlying controlled-release mechanisms. Compared with the commercial LD microspheres, some of the in-house spray-dried microspheres presented highly similar or even improved long-term release profiles, providing viable long-acting release (LAR) alternatives to the LD. The in vitro release mechanism of the peptide was shown to be controlled either by kinetics of polymer mass loss or by a second process, hypothesized to involve peptide desorption from the polymer. These data indicate spray drying can be optimized to prepare commercially relevant PLGA microsphere formulations for delivery of peptides, including the LHRHa, leuprolide.

Compression-Induced Phase Transitions of Bicalutamide

The formation of solid dispersions with the amorphous drug dispersed in the polymeric matrix improves the dissolution characteristics of poorly soluble drugs. Although they provide an improved absorption after oral administration, the recrystallization, which can occur upon absorption of moisture or during solidification and other formulation stages, serves as a major challenge. This work aims at understanding the amorphization-recrystallization changes of bicalutamide. Amorphous solid dispersions with poly(vinylpyrrolidone-co-vinyl acetate) (PVP/VA) were obtained by either ball milling or spray drying. The applied processes led to drug amorphization as confirmed using X-ray diffraction and differential scanning calorimetry. Due to a high propensity towards mechanical activation, the changes of the crystal structure of physical blends of active pharmaceutical ingredient (API) and polymer upon pressure were also examined. The compression led to drug amorphization or transition from form I to form II polymorph, depending on the composition and applied force. The formation of hydrogen bonds confirmed using infrared spectroscopy and high miscibility of drug and polymer determined using non-isothermal dielectric measurements contributed to the high stability of amorphous solid dispersions. They exhibited improved wettability and dissolution enhanced by 2.5- to 11-fold in comparison with the crystalline drug. The drug remained amorphous upon compression when the content of PVP/VA in solid dispersions exceeded 20% or 33%, in the case of spray-dried and milled systems, respectively.

Formulation technologies and advances for oral delivery of novel nitroimidazoles and antimicrobial peptides

Antibiotic resistance has become a global crisis, driving the exploration for novel antibiotics and novel treatment approaches. Among these research efforts two classes of antibiotics, bicyclic nitroimidazoles and antimicrobial peptides, have recently shown promise as novel antimicrobial agents with the possibility to treat multi-drug resistant infections. However, they suffer from the issue of poor oral bioavailability due to disparate factors: low solubility in the case of nitroimidazoles (BCS class II drugs), and low permeability in the case of peptides (BCS class III drugs). Moreover, antimicrobial peptides present another challenge as they are susceptible to chemical and enzymatic degradation, which can present an additional pharmacokinetic hurdle for their oral bioavailability. Formulation technologies offer a potential means for improving the oral bioavailability of poorly permeable and poorly soluble drugs, but there are still drawbacks and limitations associated with this approach. This review discusses in depth the challenges associated with oral delivery of nitroimidazoles and antimicrobial peptides and the formulation technologies that have been used to overcome these problems, including an assessment of the drawbacks and limitations associated with the technologies that have been applied. Furthermore, the potential for supercritical fluid technology to overcome the shortcomings associated with conventional drug formulation methods is reviewed.

Pharmacokinetics of extended-release ivermectin microspheres after oral administration to healthy pigs

We compared the pharmacokinetics of ivermectin premix and ivermectin microspheres in pigs after single and multiple administration regimes. In the single-dose experiments, 24 piglets were randomly divided into three groups and given ivermectin at 0.3 mg/kg using (a) 1.0% ivermectin administered subcutaneously, (b) 0.25% ivermectin premix orally, and (c) 0.25% ivermectin microspheres orally. In the multiple-dose experiment, 6 pigs in two equal groups received ivermectin premix and microspheres orally at 0.3 mg/kg for 7 consecutive days to monitor the valley plasma levels. The plasma samples were detected by fluorescence high-performance liquid chromatography, and concentration-time data were fitted to a noncompartmental model. After oral administration of ivermectin microspheres at a single dose, the elimination rate constant (Kel), the half-life (t_1/2 ), the peak time (T_max ), the mean residence time (MRT), and the peak concentration (C_max ) were 0.012 ± 0.0031/hr, 59.94 ± 20.18 hr, 9.50 ± 0.93 hr, 55.96 ± 11.40 hr, and 37.75 ± 3.45 ng/ml, respectively. The C_max of microspheres was not statistically different (p > .05) compared with that of premix groups (39.81 ± 5.83 ng/ml). Moreover, the AUC of the microcapsule groups was increased from 1,129.76 ± 245.62 to 1,607.33 ± 343.35 hr ng/ml compared with the premix groups, and the relative bioavailability increased by an average of 17.53% after oral administration with ivermectin microspheres. Multiple-dose administration also indicated pigs fed with ivermectin microspheres can get a higher minimum steady-state concentration and a longer maintenance time than ivermectin premix.

SLN and NLC for topical, dermal, and transdermal drug delivery

Introduction: From a biopharmaceutical standpoint, the skin is recognized as an interesting route for drug delivery. In general, small molecules are able to penetrate the stratum corneum, the outermost layer of the skin. In contrast, the delivery of larger molecules, such as peptides and proteins, remains a challenge. Nanoparticles have been exploited not only to enhance skin penetration of drugs but also to expand the range of molecules to be clinically used.Areas covered: This review focus on Solid lipid nanoparticles (SLN) and Nanostructured lipid carriers (NLC) for skin administration. We discuss the selection criteria for lipids, surfactants, and surface modifiers commonly in use in SLN/NLC, their production techniques, and the range of drugs loaded in these lipid nanoparticles for the treatment of skin disorders.Expert opinion: Depending on the lipid and surfactant composition, different nanoparticle morphologies can be generated. Both SLN and NLC are composed of lipids that resemble those of the skin and sebum, which contribute to their enhanced biocompatibility, with limited toxicological risk. SLN and NLC can be loaded with very chemically different drugs, may provide a tunable release profile, can be produced in a sterilized environment, and be scaled-up without the need for organic solvents.

Encapsulation of poorly soluble drugs in yeast glucan particles by spray drying improves dispersion and dissolution properties

In this work, novel amorphous solid dispersions based on yeast glucan particles were produced. Yeast glucan particles are hollow and porous, and they are mainly composed of amorphous polysaccharides. We hypothesized that these particles are suitable candidates for the amorphization of drugs with low water solubility. Model drugs ibuprofen and curcumin were successfully encapsulated in glucan particles by spray drying. Different spray-drying parameters were tested to evaluate the influence of atomizing droplet size and initial solid content on encapsulation efficiency. It was shown that higher solid content and, more significantly, larger droplet sizes lead to higher encapsulation efficiencies. The encapsulation efficiency of ibuprofen (10 wt%) into glucan particles was considerably improved from 41.3 ± 0.5% to 64.3 ± 0.2% by increasing initial solid content and droplet size with the two-fluid nozzle. The spray drying process was further optimized by using the ultrasonic nozzle and it was possible to achieve complete encapsulation of ibuprofen and curcumin without any precipitation of the active compound outside of the glucan particles. Overall, it was possible to produce completely amorphous composites with outstanding wettability and dispersion properties, and with significantly faster dissolution rates when compared to the micronized crude drug.

Fast Dissolving Sublingual Strips: A Novel Approach for the Delivery of Isosorbide Dinitrate

Background: Isosorbide dinitrate (ISDN) is used for treating the angina attacks. In addition, oral ISDN is available in immediate and sustained release formulations and the bioavailability of ISDN is about 20-25% when taken orally. Further, the ISDN films are developed for sublingual drug delivery by improving drug bioavailability. The present study aimed to design and evaluate the physicochemical properties of the film formulation for sublingual delivery of ISDN. Methods: In the present study, sublingual films were prepared by the solvent casting technique using the hydroxypropyl methylcellulose (HPMC) polymers (i.e., 100, 150 and 200 mg) with a different drug to polymer ratios (i.e., 1:5, 1:7.5 and 1:10). Then, ISDN was evaluated for the film appearance, drug content, surface pH, mucoadhesion force, differential scanning calorimetry (DSC), in vitro drug release, and ex vivo permeability. Results: Based on the results, F3 formulation (1:10 ISDN to HPMC ratio) showed acceptable thickness (0.93 mm), weight (11.14 mg), surface pH (7.82), moisture absorption capacity (6.08%), elasticity (>200), mucoadhesion force (18.05 N/cm2), and drug content (6.22%). Furthermore, the results demonstrated that HPMC polymer improved the characteristics of the films, modified the bioadhesiveness, and finally, enhanced elasticity. However, DSC thermogram failed to show any crystalline drug substance in the films except for F1 (immediate release) and the endothermic peak of ISDN was absent in F2 and F3 films. Therefore, the drug which was entrapped into the film was in an amorphous or disturbed-crystalline phase of the molecular dispersion or dissolved in the melted polymer in the polymeric matrix. Moreover, the drug release from the films was faster compared to the tablet® (P<0.05). Conclusion: In general, the formulation of F1 was observed to be an appropriate candidate for developing the sublingual film for the remedial use.

Continuous Formulation Approaches of Amorphous Solid Dispersions: Significance of Powder Flow Properties and Feeding Performance

Preparation and formulation of amorphous solid dispersions (ASDs) are becoming more and more popular in the pharmaceutical field because the dissolution of poorly water-soluble drugs can be effectively improved this way, which can lead to increased bioavailability in many cases. During downstream processing of ASDs, technologists need to keep in mind both traditional challenges and the newest trends. In the last decade, the pharmaceutical industry began to display considerable interest in continuous processing, which can be explained with their potential advantages such as smaller footprint, easier scale-up, and more consistent product, better quality and quality assurance. Continuous downstream processing of drug-loaded ASDs opens new ways for automatic operation. Therefore, the formulation of poorly water-soluble drugs may be more effective and safe. However, developments can be challenging due to the poor flowability and feeding properties of ASDs. Consequently, this review pays special attention to these characteristics since the feeding of the components greatly influences the content uniformity in the final dosage form. The main purpose of this paper is to summarize the most important steps of the possible ASD-based continuous downstream processes in order to give a clear overview of current course lines and future perspectives.

Stable amorphous solid dispersions of fenofibrate using hot melt extrusion technology: Effect of formulation and process parameters for a low glass transition temperature drug

Development of stable amorphous solid dispersions (ASDs) for a low glass transition temperature (Tg) drug is a challenging task. The physico-chemical properties of the drug and excipients play a critical role in developing stable ASDs. In this study, ASDs of poorly soluble fenofibrate, a drug with a low Tg, were formulated using hydroxy propyl methylcellulose acetate succinate (HPMCAS) via hot melt extrusion (HME). The feasible processing conditions were established at varying drug loads and processing temperatures. The prepared ASDs were characterized for crystallinity using differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). Fourier transform-infrared spectroscopy was performed to study the potential interactions. DSC and PXRD studies confirmed the amorphous state of fenofibrate in the prepared ASDs. A discriminative in vitro dissolution method was established to study the impact of HPMCAS grades on dissolution profile. The dissolution parameters such as dissolution efficiency, initial dissolution rate and mean dissolution rate, suggested improved dissolution characteristics compared to pure fenofibrate. Accelerated stability studies at 40 °C/75% RH showed preservation of the amorphous nature of fenofibrate in formulations with 15% drug load and in vitro drug release studies indicated similar release profiles (f2 >50). This study provides an insight into the formulation and processing of ASDs for poorly soluble drugs with low Tg.

Amorphous solid dispersion formation via solvent granulation - A case study with ritonavir and lopinavir

Herein, we evaluate the potential of using a simple solvent granulation process to prepare a binary drug amorphous solid dispersion (ASD) containing two anti-HIV drugs, ritonavir and lopinavir. The drugs were granulated onto a mixture of lactose and microcrystalline cellulose, followed by drying to remove the solvent. The resultant granules were characterized and each drug was found to be X-ray amorphous. No crystallization was observed following storage for 1 month under accelerated stability conditions (40 °C and 75% relative humidity). The dissolution behavior of the compacted granules was compared with the marketed formulation. The dissolution rate of ritonavir was found to be significantly retarded relative to the commercial product when the two drugs were co-granulated. However, comparable release could be achieved when each drug was individually granulated, followed by combination and compaction. The solvent granulation approach may be a viable method to make ASDs of low dose drugs with low crystallization tendencies.

Myth or Truth: The Glass Forming Ability Class III Drugs Will Always Form Single-Phase Homogenous Amorphous Solid Dispersion Formulations

The physical stability of amorphous solid dispersions (ASD) of active pharmaceutical ingredients (APIs) of high glass forming ability (GFA class III) is generally expected to be high among the scientific community. In this study, the ASD of ten-selected class III APIs with the two polymers, PVPVA 64 and HPMC-E5, have been prepared by spray-drying, film-casting, and their amorphicity at T0 was investigated by modulated differential scanning calorimetry and powder X-ray diffraction. It was witnessed that only five out of ten APIs form good quality amorphous solid dispersions with no phase separation and zero crystalline content, immediately after the preparation and drying process. Hence, it was further established that the classification of an API as GFA class III does not guarantee the formulation of single phase amorphous solid dispersions.

Manufacturing Different Types of Solid Dispersions of BCS Class IV Polyphenol (Daidzein) by Spray Drying: Formulation and Bioavailability

Daidzein (DZ) is a polyphenolic compound belonging to Biopharmaceutical Classification System class IV, which shows that it may have limited therapeutic effects due to its low solubility and poor bioavailability. This study aimed to obtain high-purity DZ and prepare and characterize different types of solid dispersions (SDs) in order to enhance aqueous solubility and bioavailability. Excipients were investigated in order to manufacture different types of solid dispersions (SDs). Second-generation solid dispersions (SG), third-generation solid dispersions (TG), and second- and third-generation pH-modulated solid dispersions (SD and TG pHM-SD) were produced via spray drying. The SDs were characterized and tested for in vitro DZ release and oral bioavailability. SDs have shown increased aqueous solubility and in vitro release rate. Solid-state characterization showed that DZ was in an amorphous state in most of the formulations. The enhanced aqueous solubility of TG-pHM SD was reflected by an increase in oral bioavailability, which significantly increased the maximum plasma concentration approximately 20-fold and decreased the time to reach the maximum plasma concentration. The production of pHM SDs that contain DZ via spray drying is a simple and effective approach for oral drug delivery, which has the potential to greatly reduce the dose and enhance therapeutics effects.

Spray-Dried Amorphous Solid Dispersions of Atorvastatin Calcium for Improved Supersaturation and Oral Bioavailability

Over the past few decades, the amorphous solid dispersions (ASDs) technique has emerged as a promising strategy to enhance the in vitro/in vivo characteristic of hydrophobic drugs. The low aqueous solubility and poor bioavailability of atorvastatin calcium (ATO), a lipid-lowering drug, present challenges for effective drug delivery. The objective of this work was to improve the aqueous solubility, in vitro dissolution, and oral absorption of ATO with amorphous solid dispersion technique prepared by spray-drying method. The optimized ternary formulation comprising of ATO; hydroxypropyl methylcellulose (HPMC), as a hydrophilic polymer; and sodium lauryl sulfate (SLS), as a surfactant, at a weight ratio of 1/1/0.1, showed significant improvement in aqueous solubility by ~18-fold compared to that of the free drug, and a cumulative release of 94.09% compared to a release of 59.32% of the free drug. Further, physicochemical studies via scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction revealed a change from the crystalline state of the free drug to its amorphous state in the ASD. Pharmacokinetic analysis in rats demonstrated 1.68- and 2.39-fold increments in AUC and Cmax, respectively, in the ASD over the free drug. Altogether, hydrophilic carrier-based ASDs prepared by the spray-drying technique represent a promising strategy to improve the biopharmaceutical performance of poorly soluble drugs.

Effect of Spray-Dried Particle Morphology on Mechanical and Flow Properties of Felodipine in PVP VA Amorphous Solid Dispersions

Amorphous solid dispersions (ASDs) are commonly used to enhance the oral absorption of drugs with solubility or dissolution rate limitations. Although the ASD formulation is typically constrained by physical stability and in vivo performance considerations, ASD particles can be engineered using the spray-drying process to influence mechanical and flow properties critical to tableting. Using the ASD formulation of 20% w/w felodipine dispersed in polyvinyl pyrrolidone vinyl acetate, spray-drying atomization and drying conditions were tuned to achieve 4 different powders with varying particle properties. The resulting particles ranged in volume moment mean diameter from 4 to 115 μm, bulk density from 0.05 to 0.38 g cm^-3, and morphologies of intact, collapsed, and fractured hollow spheres. Powder flowability by shear cell ranged from poor to easy flowing, whereas mechanical property tests suggested all samples will produce strong tablets at reasonable solid fractions and compression pressures. In addition, Hiestand dynamic tableting indices showed excellent dynamic bonding for 3 powders, and low viscoelasticity with high brittleness for all powders. This work demonstrates the extent spray-dried ASD particle morphologies can be engineered to achieve desired powder flow and mechanical properties to mitigate downstream processing risks and increase process throughput.

Solid dispersions of telaprevir with improved solubility prepared by co-milling: formulation, physicochemical characterization, and cytotoxicity evaluation

Telaprevir (TVR) is typically a poorly soluble drug with an extremely low bioavailability of 1.7%. Polymorph modifications cannot improve the solubility of TVR because it only has a single unsolvated crystalline form. Co-crystals also provide limited bioavailability enhancement for TVR. Thus, in this study, we increased the solubility and dissolution rate of TVR through formulations of TVR-polymer solid dispersions. Three solid dispersions of TVR were successfully prepared by co-milling with polyvinylpyrrolidone K30 (PVP), polyethylene glycol 6000, and hydroxypropyl methylcellulose (HPMC), which were characterized by different techniques. According to X-ray powder diffraction and differential scanning calorimetry results, TVR presented in amorphous form in all solid dispersions. The fourier transform infrared spectra results indicated that TVR may connect with polymers through the N-H···O or O-H···O hydrogen bonds, which were verified by molecular docking. TVR-PVP and TVR-HPMC displayed a good stability at conventional RH levels, and their thermostabilities were better than those of milled TVR. Among the three solid dispersions, TVR-HPMC showed significant solubility and dissolution rate advantages in different media. Moreover, TVR-HPMC displayed the same anticancer efficacy with crystalline TVR and presented no toxic side effects to normal liver cells. Thus, TVR-HPMC showed potential application value.

Complex amorphous solid dispersions based on poly(2-hydroxyethyl methacrylate): Study of drug release from a hydrophilic insoluble polymeric carrier in the presence and absence of a porosity increasing agent

Amorphous solid dispersions are nowadays typically made up of a drug compound and a water-soluble polymer. However, recently it has been demonstrated that amorphous solid dispersions based on insoluble polymers have a different and more delayed drug release profile, resulting in a prolonged duration of supersaturation. In this paper, binary and ternary amorphous solid dispersions based on poly(2-hydroxyethyl methacrylate) were prepared through spray drying to further investigate the potential of this type of carrier. As drug release from this matrix system was expected to be dictated by a diffusion-driven process, porosity of the formulation was adjusted by the inclusion of a water-soluble polymer. The solid state of the formulations was characterized with modulated differential scanning calorimetry, X-ray powder diffraction and thermogravimetric analysis. The release of drug and of the porosity increasing agent was measured in acidic and neutral conditions. In addition, the release performance of the spray dried product was compared with the drug release from poly(2-hydroxyethyl methacrylate) beads, which had already been reported in literature. It appeared that in the case of the spray dried poly(2-hydroxyethyl methacrylate), drug and porosity increasing agent could only be released to a certain extent due to entrapment of both compounds in the poly(2-hydroxyethyl methacrylate) network. While the chemical crosslinks of poly(2-hydroxyethyl methacrylate) beads ensured a more rigid structure with sufficient free space for drug diffusion, the spray dried product was susceptible to intense physical crosslinking upon contact with the dissolution medium.

Advanced Lipid Technologies® (ALT®): A Proven Formulation Platform to Enhance the Bioavailability of Lipophilic Compounds

Despite recent advances, the drug development process continues to face significant challenges to efficiently improve the poor solubility of active pharmaceutical ingredients (API) in aqueous media or to improve the bioavailability of lipid-based formulations. The inherent high intra- and interindividual variability of absorption of oral lipophilic drug leads to inconsistent and unpredictable bioavailability and magnitude of the therapeutic effect. For this reason, the development of lipid-based drugs remains a challenging endeavour with a high risk of failure. Therefore, effective strategies to assure a predictable, consistent, and reproducible bioavailability and therapeutic effect for lipid-based medications are needed. Different solutions to address this problem have been broadly studied, including the approaches of particle size reduction, prodrugs, salt forms, cocrystals, solid amorphous forms, cyclodextrin clathrates, and lipid-based drug delivery systems such as self-emulsifying systems and liposomes. Here, we provide a brief description of the current strategies commonly employed to increase the bioavailability of lipophilic drugs and present Advanced Lipid Technologies® (ALT®), a combination of different surfactants that has been demonstrated to improve the absorption of omega-3 fatty acids under various physiological and pathological states.

Evaluation of the bioavailability of hydrocortisone when prepared as solid dispersion

This study was conducted to formulate, characterize, and investigate the bioavailability of hydrocortisone (HCT) when prepared as solid dispersions. HCT was mixed in an organic solvent with polyethylene glycol 4000 (PEG 4000) and Kolliphor® P 407. Spray drying technique was employed to form a solid dispersion formulation at a specific ratio. Physical and chemical characterization of the formed particles were achieved using differential scanning calorimetry, scanning electron microscopy, Fourier transform infrared spectroscopy, and powder X-ray diffractometry. Furthermore, comparative in vitro and in vivo studies were conducted between the formulated particles against neat HCT. The formulated solid dispersion showed elongated particles with leaf-like structure. Formation of new chemical bonds in the formed particle was suggested due to the change in the vibrational wave numbers and the significant improvement in the bioavailability of the dispersed particles proved the importance of this technique.

Apoptosis induced by luteolin in breast cancer: Mechanistic and therapeutic perspectives

BACKGROUND

Breast cancer is worldwide commonly found malignancy in women and effective treatment is regarded as a huge clinical challenge even in the presence of several options. Extensive literature is available that demonstrating polyphenols, the richly introduce phytopharmaceuticals as anticancer agents. Among these polyphenols, resveratrol, silibinin, quercetin, genistein, curcumin reported to have an awesome potential against breast cancer. However, till now no comprehensive survey found about the anticarcinogenic properties of luteolin against breast cancer.

SCOPE AND APPROACH

This review targeted the available literature on luteolin in the treatment of breast cancer, effects in combination with other anticancer drugs with possible mechanisms.

KEY FINDINGS AND CONCLUSION

An outstanding therapeutic potential of luteolin in the treatment of breast cancer has been recorded not just as a chemopreventive and chemotherapeutic agent yet complemented by its synergistic effects with other anticancer therapies such as cyclophosphamide, doxorubicin, and NSAID such as celecoxib, and possible underlying mechanisms. Ideally, this review will open new dimensions for luteolin as an effective and safe therapeutic agent in diminishing breast cancer.

Possibilities and Limiting Factors for the Use of Dissolution as a Quality Control Tool to Detect Presence of Crystallinity for Amorphous Solid Dispersions: An Experimental and Modeling Investigation

In this article, experiments on tablets containing a model compound, grazoprevir, were conducted to explore how media selection for a quality control dissolution method can influence the sensitivity for the dissolution method toward drug crystallinity detection in an amorphous solid dispersion formulation. The experiment shows that under ideal nonsink conditions with respect to crystalline solubility, dissolution can indeed be predictive of crystallinity in the formulation. However, the limit of detection for crystallinity with quality control dissolution can change based on inherent variabilities in the drug product. In addition, it is demonstrated that the method's sensitivity and accuracy might be reduced if the crystalline particles are sufficiently small with respect to the solid dispersion particles. To further demonstrate the limits of the dissolution method, a dissolution model was also explored to simulate and predict the sensitivity of the dissolution response toward crystallinity based on solubility in the media and particle size of the crystals.

Solid dispersion technology as a strategy to improve the bioavailability of poorly soluble drugs

Over the last half-century, solid dispersions (SDs) have been intensively investigated as a strategy to improve drugs solubility and dissolution rate, enhancing oral bioavailability. In this review, an overview of the state of the art of SDs technology is presented, focusing on their classification, the main preparation methods, the limitations associated with their instability, and the marketed products. To fully take advantage of SDs potential, an improvement in their physical stability and the ability to prolong the supersaturation of the drug in gastrointestinal fluids is required, as well as a better scientific understanding of scale-up for defining a robust manufacturing process. Taking these limitations into account will contribute to increase the number of marketed pharmaceutical products based on SD technology.

Combination of Colloidal Silicon Dioxide with Spray-Dried Solid Dispersion to Facilitate Discharge from an Agitated Dryer

A feasibility evaluation of the addition of fumed silica (SiO₂) into an agitated dryer to aid spray-dried solid dispersion intermediate (SDSDi) flow during secondary drying and discharge is described. The quantity of SiO₂ to enhance the flow character of SDSDi was assessed by measuring particle size distribution, bulk density, and flow-through-an-orifice. Results indicate that the addition of the SiO₂ did not alter the drying kinetics and did not impact the bulk particle size distribution of the SDSDi. While bulk density of SDSDi increased with the addition of SiO₂, the flow, and thus the recovery of the SDSDi-SiO₂ batch from the secondary dryer, was significantly higher than that for the intermediate alone. Imaging indicated uniform distribution of SiO₂ in the bulk powder and coating on intermediate particles. Premixing and co-sieving of the SiO₂ with a portion of pre-dry SDSDi promotes the uniform distribution of SiO₂ within the bulk powder bed.

Crystallization Tendency of Pharmaceutical Glasses: Relevance to Compound Properties, Impact of Formulation Process, and Implications for Design of Amorphous Solid Dispersions

Amorphous solid dispersions (ASDs) are important formulation strategies for improving the dissolution process and oral bioavailability of poorly soluble drugs. Physical stability of a candidate drug must be clearly understood to design ASDs with superior properties. The crystallization tendency of small organics is frequently estimated by applying rapid cooling or a cooling/reheating cycle to their melt using differential scanning calorimetry. The crystallization tendency determined in this way does not directly correlate with the physical stability during isothermal storage, which is of great interest to pharmaceutical researchers. Nevertheless, it provides important insights into strategy for the formulation design and the crystallization mechanism of the drug molecules. The initiation time for isothermal crystallization can be explained using the ratio of the glass transition and storage temperatures (T_g/T). Although some formulation processes such as milling and compaction can enhance nucleation, the T_g/T ratio still works for roughly predicting the crystallization behavior. Thus, design of accelerated physical stability test may be possible for ASDs. The crystallization tendency during the formulation process and the supersaturation ability of ASDs may also be related to the crystallization tendency determined by thermal analysis. In this review, the assessment of the crystallization tendency of pharmaceutical glasses and its relevance to developmental studies of ASDs are discussed.

Scale-up of pharmaceutical spray drying using scale-up rules: A review

Spray drying is one of the widely used manufacturing processes in pharmaceutical industry. While there are voluminous experimental studies pertaining to the impact of various process-formulation parameters on the quality attributes of spray dried powders such as particle size, morphology, density, and crystallinity, there is scant information available in the literature regarding process scale-up. Here, we first analyze salient features of scale-up attempts in literature. Then, spray drying process is analyzed considering the fundamental physical transformations involved, i.e., atomization, drying, and gas-solid separation. Each transformation is scrutinized from a scale-up perspective with non-dimensional parameters & multi-scale analysis, and comprehensively discussed in engineering context. Successful scale-up entails similar key response variables from each transformation across various scales. These variables are identified as droplet size distribution, outlet temperature, relative humidity, separator pressure loss coefficient, and collection efficiency. Instead of trial-and-error-based approaches, this review paper advocates the use of mechanistic models and scale-up rules for establishing design spaces for the process variables involved in each transformation of spray drying. While presenting a roadmap for process development and scale-up, the paper demonstrates how to bridge the current gap in spray drying scale-up via a rational understanding of the fundamental transformations.

The Self-Assembly Phenomenon of Poloxamers and Its Effect on the Dissolution of a Poorly Soluble Drug from Solid Dispersions Obtained by Solvent Methods

The self-assembly phenomenon of amphiphiles has attracted particular attention in recent years due to its wide range of applications. The formation of nanoassemblies able to solubilize sparingly water-soluble drugs was found to be a strategy to solve the problem of poor solubility of active pharmaceutical ingredients. Binary and ternary solid dispersions containing Biopharmaceutics Classification System (BCS) class II drug bicalutamide and either Poloxamer®188 or Poloxamer®407 as the surface active agents were obtained by either spray drying or solvent evaporation under reduced pressure. Both processes led to morphological changes and a reduction of particle size, as confirmed by scanning electron microscopy and laser diffraction measurements. The increase in powder wettability was confirmed by means of contact angle measurements. The effect of an alteration of the crystal structure was followed by powder X-ray diffractometry while thermal properties were determined using differential scanning calorimetry. Interestingly, bicalutamide exhibited a polymorph transition after spray drying with the poloxamer and polyvinylpyrrolidone (PVP), while the poloxamer underwent partial amorphization. Moreover, due to the surface activity of the carrier, the solid dispersions formed nanoaggregates in water, as confirmed using dynamic light scattering measurements. The aggregates measuring 200⁻300 nm in diameter were able to solubilize bicalutamide inside the hydrophobic inner parts. The self-assembly of binary systems was found to improve the amount of dissolved bicalutamide by 4- to 8-fold in comparison to untreated drug. The improvement in drug dissolution was correlated with the solubilization of poorly soluble molecules by macromolecules, as assessed using emission spectroscopy.

Dissolution and bioavailability improvement of bioactive apigenin using solid dispersions prepared by different techniques

Apigenin (APG) is a poorly soluble bioactive compound/nutraceutical which shows poor bioavailability upon oral administration. Hence, the objective of this research work was to develop APG solid dispersions (SDs) using different techniques with the expectation to obtain improvement in its in vitro dissolution rate and in vivo bioavailability upon oral administration. Different SDs of APG were prepared by microwave, melted and kneaded technology using pluronic-F127 (PL) as a carrier. Prepared SDs were characterized using "thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infra-red (FTIR) spectrometer, powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM)". After characterization, prepared SDs of APG were studied for in vitro drug release/dissolution profile and in vivo pharmacokinetic studies. The results of TGA, DSC, FTIR, PXRD and SEM indicated successful formation of APG SDs. In vitro dissolution experiments suggested significant release of APG from all SDs (67.39-84.13%) in comparison with control (32.74%). Optimized SD of APG from each technology was subjected to in vivo pharmacokinetic study in rats. The results indicated significant improvement in oral absorption of APG from SD prepared using microwave and melted technology in comparison with pure drug and commercial capsule. The enhancement in oral bioavailability of APG from microwave SD (319.19%) was 3.19 fold as compared with marketed capsule (100.00%). Significant enhancement in the dissolution rate and oral absorption of APG from SD suggested that developed SD systems can be successfully used for oral drug delivery system of APG.

Building a better particle: Leveraging physicochemical understanding of amorphous solid dispersions and a hierarchical particle approach for improved delivery at high drug loadings

Amorphous solid dispersions are a promising option for managing compounds with poor aqueous solubility. However, for compounds with high melting points, thermal stability limitations, or poor solubility in volatile solvents, conventional routes of hot melt extrusion or spray drying may not be viable. Co-precipitated amorphous dispersions (cPAD) can provide a solution. For the material studied in this paper, the cPAD material that was seemingly identical to spray dried material in terms of being single phase amorphous (as measured by DSC and XRD ) but showed slower dissolution behavior. It was identified that physical properties of the cPAD material could be improved to enhance wettability and improve dissolution performance. This was achieved by incorporating the cPAD material into a matrix of water soluble excipients generated via evaporative isolation routes. Importantly, this approach appears to offer another route to further increase the drug load in final dosage units and is significant as increased drug loading generally results in slower or incomplete release. Results showed successful proof of concept via in vitro biorelevant dissolution and confirmatory canine pharmacokinetic studies yielding comparable exposure for capsules comprised of conventional spray dried material as well as capsules with elevated drug load comprised of cPAD hierarchical particles.

Process Optimization and Upscaling of Spray-Dried Drug-Amino acid Co-Amorphous Formulations

The feasibility of upscaling the formulation of co-amorphous indomethacin-lysine from lab-scale to pilot-scale spray drying was investigated. A 2² full factorial design of experiments (DoE) was employed at lab scale. The atomization gas flow rate (F_atom, from 0.5 to 1.4 kg/h) and outlet temperature (T_out, from 55 to 75 °C) were chosen as the critical process parameters. The obtained amorphization, glass transition temperature, bulk density, yield, and particle size distribution were chosen as the critical quality attributes. In general, the model showed low F_atom and high T_out to be beneficial for the desired product characteristics (a co-amorphous formulation with a low bulk density, high yield, and small particle size). In addition, only a low F_atom and high T_out led to the desired complete co-amorphization, while a minor residual crystallinity was observed with the other combinations of F_atom and T_out. Finally, upscaling to a pilot scale spray dryer was carried out based on the DoE results; however, the drying gas flow rate and the feed flow rate were adjusted to account for the different drying chamber geometries. An increased likelihood to achieve complete amorphization, because of the extended drying chamber, and hence an increased residence time of the droplets in the drying gas, was found in the pilot scale, confirming the feasibility of upscaling spray drying as a production technique for co-amorphous systems.

Lipids and polymers in pharmaceutical technology: Lifelong companions

In pharmaceutical technology, lipids and polymers are considered pillar excipients for the fabrication of most dosage forms, irrespective of the administration route. They play various roles ranging from support vehicles to release rate modifiers, stabilizers, solubilizers, permeation enhancers and transfection agents. Focusing on selected applications, which were discussed at the Annual Scientific Meeting of the Gattefossé Foundation 2018, this manuscript recapitulates the fundamental roles of these two important classes of excipients, either employed alone or in combination, and provides insight on their functional properties in various types of drug formulations. Emphasis is placed on oral formulations for the administration of active pharmaceutical ingredients with low aqueous solubilities or poor permeation properties. Additionally, this review article covers the use of lipids and polymers in the design of colloidal injectable delivery systems, and as substrates in additive manufacturing technologies for the production of tailor-made dosage forms.

Drug nanoclusters formed in confined nano-cages of CD-MOF: dramatic enhancement of solubility and bioavailability of azilsartan

Tremendous efforts have been devoted to the enhancement of drug solubility using nanotechnologies, but few of them are capable to produce drug particles with sizes less than a few nanometers. This challenge has been addressed here by using biocompatible versatile γ-cyclodextrin (γ-CD) metal-organic framework (CD-MOF) large molecular cages in which azilsartan (AZL) was successfully confined producing clusters in the nanometer range. This strategy allowed to improve the bioavailability of AZL in Sprague-Dawley rats by 9.7-fold after loading into CD-MOF. The apparent solubility of AZL/CD-MOF was enhanced by 340-fold when compared to the pure drug. Based on molecular modeling, a dual molecular mechanism of nanoclusterization and complexation of AZL inside the CD-MOF cages was proposed, which was confirmed by small angle X-ray scattering (SAXS) and synchrotron radiation-Fourier transform infrared spectroscopy (SR-FTIR) techniques. In a typical cage-like unit of CD-MOF, three molecules of AZL were included by the γ-CD pairs, whilst other three AZL molecules formed a nanocluster inside the 1.7 nm sized cavity surrounded by six γ-CDs. This research demonstrates a dual molecular mechanism of complexation and nanoclusterization in CD-MOF leading to significant improvement in the bioavailability of insoluble drugs.