Determination of drug-polymer solubility from supersaturated spray-dried amorphous solid dispersions: A case study with Efavirenz and Soluplus®

Developing Soluplus®-Based Microparticle Amorphous Solid Dispersions with High Drug Loading for Enhanced Celecoxib Dissolution via Electrospraying

Amorphous solid dispersion (ASD) is one of the most studied strategies for improving the dissolution performance of poorly water-soluble drugs, but ASDs often have low drug loadings, thereby necessitating larger dosage sizes. This study intended to create Soluplus® (SOL)-based microparticle ASDs with high drug loading (up to 60 w/w%) and long-term stability (at least 16 months) using electrospraying to enhance the dissolution of poorly water-soluble celecoxib (CEL). X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses showed that the electrosprayed SOL-CEL microparticles were amorphous, and Fourier transform infrared spectroscopy (FTIR) data indicated the presence of hydrogen bonding between SOL and CEL in the microparticles, which helped stabilize the ASDs. In vitro dissolution studies demonstrated that these ASDs improved the CEL dissolution rate by up to 8.2-fold compared to the crystalline form. Electrospraying presents a promising alternative to conventional methods like hot-melt extrusion (HME) and spraying drying (SD) for the production of ASDs, providing simplicity, high drug loading capability and long-term stability, thus catering to a variety of poorly water-soluble drugs.

Self-microemulsifying drug delivery system-based gastroretentive in situ raft of pazopanib with enhanced solubility and bioavailability

Pazopanib hydrochloride (PZH) is a Biopharmaceutics Classification System class II drug that faces challenges at the formulation forefront including low aqueous solubility (0.043 mg/mL) and poor oral bioavailability (14-39%). The present investigation aimed to develop a self-microemulsifying drug delivery system (SMEDDS) of PZH using a blend of Capryol® 90, Labrasol®, and propylene glycol to improve its solubility. Furthermore, a sustained-release SMEDDS-based gastroretentive floating system was developed and optimized using the Central Composite Design approach of DoE. The optimized SMEDDS-based in situ gelling raft, R-SM-PZH, exhibited minimal floating lag time (3.09 ± 0.8 s), optimal viscosity (1229.4 ± 20.9 cP) and density (0.327 ± 0.15 g/mL) as compared to other formulations under study. Additionally, R-SM-PZH was evaluated for its in vitro dissolution in FaSSGF and FeSSGF, pharmacokinetic profile, and MTT assay (against NCI-H460 lung cancer cells) compared to pure PZH. A 12 h sustained release, three-fold augmentation in dissolution rate and bioavailability, and 15-fold enhancement in cytotoxicity were observed in comparison to pure PZH. Thus, the SMEDDS-based in situ gelling raft presents a promising approach to advancing the developability potential of PZH.

Electromagnetic drop-on-demand (DoD) technology as an innovative platform for amorphous solid dispersion production

Production of amorphous solid dispersions (ASDs) is an effective strategy to promote the solubility and bioavailability of poorly water soluble medicinal substances. In general, ASD is manufactured using a variety of classic and modern techniques, most of which rely on either melting or solvent evaporation. This proof-of-concept study is the first ever to introduce electromagnetic drop-on-demand (DoD) technique as an alternative solvent evaporation-based method for producing ASDs. Herein 3D printing of ASDs for three drug-polymer combinations (efavirenz-Eudragit L100-55, lumefantrine-hydroxypropyl methylcellulose acetate succinate, and favipiravir-polyacrylic acid) was investigated to ascertain the reliability of this technique. Polarized light microscopy, differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and Fourier Transform  Infrared (FTIR) spectroscopy results supported the formation of ASDs for the three drugs by means of DoD 3D printing, which significantly increases the equilibrium solubility of efavirenz from 0.03 ± 0.04 µg/ml to 21.18 ± 4.20 µg/ml, and the equilibrium solubility of lumefantrine from 1.26 ± 1.60 µg/ml to 20.21 ± 6.91 µg/ml. Overall, the reported findings show how this new electromagnetic DoD technology can have a potential to become a cutting-edge 3D printing solvent-evaporation technique for on-demand and continuous manufacturing of ASDs for a variety of drugs.

Amorphous solid dispersion augments the bioavailability of phloretin and its therapeutic efficacy via targeting mTOR/SREBP-1c axis in NAFLD mice

The escalating incidences of non-alcoholic fatty liver disease (NAFLD) and associated metabolic disorders are global health concerns. Phloretin (Ph) is a natural phenolic compound, that exhibits a wide array of pharmacological actions including its efficacy towards NAFLD. However, poor solubility and bioavailability of phloretin limits its clinical translation. Here, to address this concern we developed an amorphous solid dispersion of phloretin (Ph-SD) using Soluplus® as a polymer matrix. We further performed solid-state characterization through SEM, P-XRD, FT-IR, and TGA/DSC analysis. Phloretin content, encapsulation efficiency, and dissolution profile of the developed formulation were evaluated through reverse phase HPLC. Finally, the oral bioavailability of Ph-SD and its potential application in the treatment of experimental NAFLD mice was investigated. Results demonstrated that the developed formulation (Ph-PD) augments the dissolution profile and oral bioavailability of the native phloretin (Ph). In NAFLD mice, histopathological studies revealed the preventive effect of Ph-SD on degenerative changes, lipid accumulation, and inflammation in the liver. Ph-SD also improved the serum lipid profile, ALT, and AST levels and lowered the interleukin-6 and tumor necrosis factor-α levels in the liver. Further, Ph-SD reduced fibrotic changes in the liver tissues and attenuates NAFLD progression by blocking the mTOR/SREBP-1c pathway. In a nutshell, the results of our study strongly suggest that Ph-SD has the potential to be a therapeutic candidate in the treatment of NAFLD and can be carried forward for further clinical studies.

The Self-Assembly Soluplus Nanomicelles of Nobiletin in Aqueous Medium Based on Solid Dispersion and Their Increased Hepatoprotective Effect on APAP-Induced Acute Liver Injury

Purpose

APAP-induced liver injury (AILI) is a common cause of acute liver failure (ALF). Nobiletin (NOB) is a potential hepatoprotective agent for the treatment of APAP-induced liver injury. However, the poor solubility and low bioavailability of NOB hinders its application. In this study, a novel self-assembly nano-drug delivery system of nobiletin (solid dispersion of NOB, termed as NOB/SD) was developed based on solid dispersion technology to improve the bioavailability and hepatoprotective ability of NOB for APAP-induced liver injury therapy.

Methods

The optimized NOB/SD system was constructed using the amphiphilic copolymers of Soluplus and PVP/VA 64 via hot melt extrusion technology (HME). NOB/SD was characterized by solubility, physical interaction, drug release behavior, and stability. The bioavailability and hepatoprotective effects of NOB/SD were evaluated in vitro and in vivo.

Results

NOB/SD maintained NOB in matrix carriers in a stable amorphous state, and self-assembled NOB-loaded nanomicelles in water. Nanostructures based on solid dispersion technology exhibited enhanced solubility, improved release behavior, and promoted cellular uptake and anti-apoptosis in vitro. NOB/SD displayed significantly improved bioavailability in healthy Sprague Dawley (SD) rats in vivo. Furthermore, NOB/SD alleviated the APAP-induced liver injury by improving anti-oxidative stress with reactive oxygen species (ROS) scavenging and nuclear factor erythroid 2-related factor 2 (Nrf2) activation.

Conclusion

These results suggested that NOB/SD could be considered as a promising hepatoprotective nano-drug delivery system for attenuating APAP-induced acute liver injury with superior bioavailability and efficient hepatoprotection, which might provide an effective strategy for APAP-induced acute liver injury prevention and treatment.

Preparation and evaluation of astaxanthin-loaded 2-hydroxypropyl-beta-cyclodextrin and Soluplus® nanoparticles based on electrospray technology

BACKGROUND

Astaxanthin is a type of food-derived active ingredient with antioxidant, antidiabetic and non-toxicity functions, but its poor solubility and low bioavailability hinder further application in food industry. In the present study, through inclusion technologies, micellar solubilization and electrospray techniques, we prepared astaxanthin nanoparticles before optimizing the formulation to regulate the physical and chemical properties of micelles. We accomplished the preparation of astaxanthin nanoparticle delivery system based on single needle electrospray technology through use of 2-hydroxypropyl-β-cyclodextrin and Soluplus® to improveme the release behavior of the nanocarrier.

RESULTS

Through this experiment, we successfully prepared astaxanthin nanoparticles with a particle size of approximately 80 nm, which was further verified with scanning electron microscopy and transmission electron microscopy. Furthermore, the encapsulation of astaxanthin molecules into the carrier nanoparticles was verified via the results of attenuated total reflectance intensity and X-ray powder diffraction techniques. The in vitro release behavior of astaxanthin nanoparticles was different in media that contained 0.5% Tween 80 (pH 1.2, 4.5 and 6.8) buffer solution and distilled water. Also, we carried out a pharmacokinetic study of astaxanthin nanoparticles, in which it was observed that astaxanthin nanoparticle showed an effect of immediate release and significant improved bioavailability.

CONCLUSION

2-hydroxypropyl-β-cyclodextrin and Soluplus® were used in the present study as a hydrophilic nanocarrier that could provide a simple way of encapsulating natural function food with repsect to improving the solubility and bioavailability of poorly water-soluble ingredients. © 2023 Society of Chemical Industry.

Continuous Manufacturing and Molecular Modeling of Pharmaceutical Amorphous Solid Dispersions

Amorphous solid dispersions enhance solubility and oral bioavailability of poorly water-soluble drugs. The escalating number of drugs with poor aqueous solubility, poor dissolution, and poor oral bioavailability is an unresolved problem that requires adequate interventions. This review article highlights recent solubility and bioavailability enhancement advances using amorphous solid dispersions (ASDs). The review also highlights the mechanism of enhanced dissolution and the challenges faced by ASD-based products, such as stability and scale-up. The role of process analytical technology (PAT) supporting continuous manufacturing is highlighted. Accurately predicting interactions between the drug and polymeric carrier requires long experimental screening methods, and this is a space where computational tools hold significant potential. Recent advancements in data science, computational tools, and easy access to high-end computation power are set to accelerate ASD-based research. Hence, particular emphasis has been given to molecular modeling techniques that can address some of the unsolved questions related to ASDs. With the advancement in PAT tools and artificial intelligence, there is an increasing interest in the continuous manufacturing of pharmaceuticals. ASDs are a suitable option for continuous manufacturing, as production of a drug product from an ASD by direct compression is a reality, where the addition of multiple excipients is easy to avoid. Significant attention is necessary for ongoing clinical studies based on ASDs, which is paving the way for the approval of many new ASDs and their introduction into the market.

Development and Characterization of Oral Raft Forming In Situ Gelling System of Neratinib Anticancer Drug Using 32 Factorial Design

Neratinib (NTB) is an irreversible inhibitor of pan-human epidermal growth factor receptor (HER-2) tyrosine kinase and is used in the treatment of breast cancer. It is a poorly aqueous soluble drug and exhibits extremely low oral bioavailability at higher pH, leading to a diminishing of the therapeutic effects in the GIT. The main objective of the research was to formulate an oral raft-forming in situ gelling system of NTB to improve gastric retention and drug release in a controlled manner and remain floating in the stomach for a prolonged time. In this study, NTB solubility was enhanced by polyethylene glycol (PEG)-based solid dispersions (SDs), and an in situ gelling system was developed and optimized by a two-factor at three-level (3²) factorial design. It was analyzed to study the impact of two independent variables viz sodium alginate [A] and HPMC K4M [B] on the responses, such as floating lag time, percentage (%) water uptake at 2 h, and % drug release at 6 h and 12 h. Among various SDs prepared using PEG 6000, formulation 1:3 showed the highest drug solubility. FT-IR spectra revealed no interactions between the drug and the polymer. The percentage of drug content in NTB SDs ranged from 96.22 ± 1.67% to 97.70 ± 1.89%. The developed in situ gel formulations exhibited a pH value of approximately 7. An in vitro gelation study of the in situ gel formulation showed immediate gelation and was retained for a longer period. From the obtained results of 3² factorial designs, it was observed that all the selected factors had a significant effect on the chosen response, supporting the precision of design employed for optimization. Thus, the developed oral raft-forming in situ gelling system of NTB can be a promising and alternate approach to enhance retention in the stomach and to attain sustained release of drug by floating, thereby augmenting the therapeutic efficacy of NTB.

Improved Bioavailability of Poorly Water-Soluble Drug by Targeting Increased Absorption through Solubility Enhancement and Precipitation Inhibition

Itraconazole (ITZ) is a class II drug according to the biopharmaceutical classification system. Its solubility is pH 3-dependent, and it is poorly water-soluble. Its pKa is 3.7, which makes it a weak base drug. The aim of this study was to prepare solid dispersion (SD) pellets to enhance the release of ITZ into the gastrointestinal environment using hot-melt extrusion (HME) technology and a pelletizer. The pellets were then filled into capsules and evaluated in vitro and in vivo. The ITZ changed from a crystalline state to an amorphous state during the HME process, as determined using DSC and PXRD. In addition, its release into the gastrointestinal tract was enhanced, as was the level of ITZ recrystallization, which was lower than the marketed drug (Sporanox^®), as assessed using an in vitro method. In the in vivo study that was carried out in rats, the AUC_0-48h of the commercial formulation, Sporanox^®, was 1073.9 ± 314.7 ng·h·mL^-1, and the bioavailability of the SD pellet (2969.7 ± 720.6 ng·h·mL^-1) was three-fold higher than that of Sporanox^® (*** p < 0.001). The results of the in vivo test in beagle dogs revealed that the AUC_0-24h of the SD-1 pellet (which was designed to enhance drug release into gastric fluids) was 3.37 ± 3.28 μg·h·mL^-1 and that of the SD-2 pellet (which was designed to enhance drug release in intestinal fluids) was 7.50 ± 4.50 μg·h·mL^-1. The AUC of the SD-2 pellet was 2.2 times higher than that of the SD-1 pellet. Based on pharmacokinetic data, ITZ would exist in a supersaturated state in the area of drug absorption. These results indicated that the absorption area is critical for improving the bioavailability of ITZ. Consequently, the bioavailability of ITZ could be improved by inhibiting precipitation in the absorption area.

Amorphous Form of Carvedilol Phosphate-The Case of Divergent Properties

The amorphous form of carvedilol phosphate (CVD) was obtained as a result of grinding. The identity of the obtained amorphous form was confirmed by powder X-ray diffraction (PXRD), different scanning calorimetry (DSC), and FT-IR spectroscopy. The process was optimized in order to obtain the appropriate efficiency and time. The crystalline form of CVD was used as the reference standard. Solid dispersions of crystalline and amorphous CVD forms with hydrophilic polymers (hydroxypropyl-β-cyclodextrin, Pluronic^® F-127, and Soluplus^®) were obtained. Their solubility at pH 1.2 and 6.8 was carried out, as well as their permeation through a model system of biological membranes suitable for the gastrointestinal tract (PAMPA-GIT) was established. The influence of selected polymers on CVD properties was defined for the amorphous form regarding the crystalline form of CVD. As a result of grinding (four milling cycles lasting 15 min with 5 min breaks), amorphous CVD was obtained. Its presence was confirmed by the “halo effect” on the diffraction patterns, the disappearance of the peak at 160.5 °C in the thermograms, and the changes in position/disappearance of many characteristic bands on the FT-IR spectra. As a result of changes in the CVD structure, its lower solubility at pH 1.2 and pH 6.8 was noted. While the amorphous dispersions of CVD, especially with Pluronic^® F-127, achieved better solubility than combinations of crystalline forms with excipients. Using the PAMPA-GIT model, amorphous CVD was assessed as high permeable (Papp > 1 × 10⁻⁶ cm/s), similarly with its amorphous dispersions with excipients (hydroxypropyl-β-cyclodextrin, Pluronic^® F-127, and Soluplus^®), although in their cases, the values of apparent constants permeability were decreased.

Analytical and Computational Methods for the Determination of Drug-Polymer Solubility and Miscibility

In the pharmaceutical industry, poorly water-soluble drugs require enabling technologies to increase apparent solubility in the biological environment. Amorphous solid dispersion (ASD) has emerged as an attractive strategy that has been used to market more than 20 oral pharmaceutical products. The amorphous form is inherently unstable and exhibits phase separation and crystallization during shelf life storage. Polymers stabilize the amorphous drug by antiplasticization, reducing molecular mobility, reducing chemical potential of drug, and increasing glass transition temperature in ASD. Here, drug-polymer miscibility is an important contributor to the physical stability of ASDs. The current Review discusses the basics of drug-polymer interactions with the major focus on the methods for the evaluation of solubility and miscibility of the drug in the polymer. Methods for the evaluation of drug-polymer solubility and miscibility have been classified as thermal, spectroscopic, microscopic, solid-liquid equilibrium-based, rheological, and computational methods. Thermal methods have been commonly used to determine the solubility of the drug in the polymer, while other methods provide qualitative information about drug-polymer miscibility. Despite advancements, the majority of these methods are still inadequate to provide the value of drug-polymer miscibility at room temperature. There is still a need for methods that can accurately determine drug-polymer miscibility at pharmaceutically relevant temperatures.

Effect of High-Energy Milling on the Dissolution of Anti-HIV Drug Efavirenz in Different Solvents

The anti-HIV drug efavirenz (EFV) displays low and variable bioavailability because of its poor aqueous solubility. Ball milling is a simple and cost-effective alternative to traditional micronization to improve the solubility and dissolution rate of EFV. A multibody dynamics model was employed to optimize the milling process parameters, while the motion of the balls in the mill jar was monitored in operando. This led to a better understanding of the milling dynamics for efficient comminution and enhancement of EFV dissolution. The variability of results for different EFV batches was also considered. Depending on the EFV batch, there were intrinsic differences in how the milling affected the dissolution behavior and inhibition of HIV-1 infection. High-energy grinding is more effective on EFV materials containing an amorphous fraction; it helps to remove agglomeration and enhances dissolution. Polyvinylpyrrolidone (PVP) addition improves the dissolution by forming a hydrophilic layer on the EFV surface, thereby increasing the drug wettability. Polymorphism also affects the quality, dosage, and effectiveness of the drug. The mechanical stress effect and PVP addition on the EFV polymorphic transformation were monitored by X-ray powder diffraction, while the residual of ground EFV was collected after dissolution, analyzed by scanning electron microscopy, and provided insights into the morphological changes.

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

Amorphous solid dispersions (ASDs) are being employed frequently to improve bioavailability of poorly soluble molecules by enhancing the rate and extant of dissolution in drug product development process. These systems comprise of an amorphous active pharmaceutical ingredient stabilized by a polymer matrix to provide enhanced stability. This review discussed the methodologies of preparation and characterization of ASDs with an emphasis on understanding and predicting stability. Rational selection of polymers, preparation techniques with its advantages and disadvantages and characterization of polymeric amorphous solid dispersions have discussed. Stability aspects have been described as per ICH guidelines which intend to depend on selection of polymers and preparation methods of ASD. The mechanism involved on improvement of bioavailability also considered. Regulatory importance of ASD and current evolving details of QBD approach were reviewed. Amorphous products and particularly ASDs are currently most emerging area in the pharmaceutical field. This strategic approach presents huge impact and advantageous features concerning the overall improvement of drug product performance in clinical settings which ultimately lead to drug product approval by leading regulatory agencies into the market.

Developmental Strategies of Curcumin Solid Dispersions for Enhancing Bioavailability

BACKGROUND

Although curcumin has been demonstrated to be beneficial in treating various diseases, its low solubility, chemical stability and bioavailability limit its application, especially in cancer therapy.

METHODS

Solid dispersions have been utilized in the last few decades to improve the bioavailability and stability of curcumin.

RESULTS

However, there is a lack of summaries and classifications of the methods for preparing curcumin with this technology. The current review aims to overview the strategies used to develop solid dispersions containing curcumin for improving drug delivery. The classification of techniques for creating solid dispersions for curcumin was summarized, including systems for protecting curcumin degradation despite its chemical stability. The applications of advanced nanotechnologies in recent studies of solid dispersions were also discussed to explain the roles of nanoparticles in formulations.

CONCLUSION

This overview of recent developments in formulating solid dispersions for improving curcumin bioavailability will contribute to future studies of curcumin for clinical development.

Development of Pediatric Orodispersible Tablets Based on Efavirenz as a New Therapeutic Alternative

BACKGROUND

Efavirenz is the most used medication in the treatment of Acquired Immunodeficiency Syndrome (AIDS). The limited number of pediatric antiretroviral formulations approved by regulatory agencies is the most significant obstacle to adequate and efficient pharmacotherapy for this group of patients. The efavirenz has excellent therapeutic potential, but has low aqueous solubility/bioavailability.

METHODS

To minimize these limitations, multicomponent systems with β-cyclodextrin and polyvinylpyrrolidone K-30 were obtained. Due to the limited number of pediatric antiretroviral formulations, the development of a pediatric orodispersible tablet is an alternative that is thought easy to administer, since it disintegrates rapidly in the oral cavity. The multicomponent systems were obtained by the method of kneading and characterized by solubility test, X-ray diffraction, differential scanning calorimetry and infrared absorption spectroscopy by Fourier transform. The orodispersible tablets were prepared by direct compression. The quality control of hardness, friability, disintegration, and dissolution was performed. The influence of the components of the formulation on the characteristics of the tablets was evaluated through a 22 factorial design added with three central points, to compare the effect of the dependent variables on the responses.

RESULTS

An increase in drug solubility was observed, with a decrease in crystallinity. Besides that, an excellent dissolution profile presented with more than 83% of the drug's content dissolved in less than 15 minutes. Satisfactory disintegration time and friability were observed.

CONCLUSION

It was observed that reduced concentrations of mannitol decreased the hardness and disintegration time of the formulations. The orodispersible tablet composed of efavirenz: β- cyclodextrin: polyvinylpyrrolidone, favors greater absorption and bioavailability. It has several advantages for pediatric patients, as the dosage form disintegrates quickly in the mouth and does not require water for administration, thereby improving patient compliance with the treatment.