Probing the Interplay between Amorphous Solid Dispersion Stability and Polymer Functionality

Microfluidics-on-a-chip for designing celecoxib-based amorphous solid dispersions: when the process shapes the product

The fundamental idea underlying the use of amorphous solid dispersions (ASDs) is to make the most of the solubility advantage of the amorphous form of a drug. However, the drug stability becomes compromised due to the higher free energy and disorder of molecular packing in the amorphous phase, leading to crystallization. Polymers are used as a matrix to form a stable homogeneous amorphous system to overcome the stability concern. The present work aims to design ASD-based formulations under the umbrella of quality by design principles for improving oral drug bioavailability, using celecoxib (CXB) as a model drug. ASDs were prepared from selected polymers and tested both individually and in combinations, using various manufacturing techniques: high-shear homogenization, high-pressure homogenization, microfluidics-on-a-chip, and spray drying. The resulting dispersions were further optimized, resorting to a 32 full-factorial design, considering the drug:polymers ratio and the total solid content as variables. The formulated products were evaluated regarding analytical centrifugation and the influence of the different polymers on the intrinsic dissolution rate of the CXB-ASDs. Microfluidics-on-a-chip led to the amorphous status of the formulation. The in vitro evaluation demonstrated a remarkable 26-fold enhancement in the intrinsic dissolution rate, and the translation of this formulation into tablets as the final dosage form is consistent with the observed performance enhancement. These findings are supported by ex vivo assays, which exhibited a two-fold increase in permeability compared to pure CXB. This study tackles the bioavailability hurdles encountered with diverse active compounds, offering insights into the development of more effective drug delivery platforms.

Enhancing hepatoprotective action: oxyberberine amorphous solid dispersion system targeting TLR4

Oxyberberine (OBB) is a significant natural compound, with excellent hepatoprotective properties. However, the poor water solubility of OBB hinders its release and absorption thus resulting in low bioavailability. To overcome these drawbacks of OBB, amorphous spray-dried powders (ASDs) of OBB were formulated. The dissolution, characterizations, and pharmacokinetics of OBB-ASDs formulation were investigated, and its hepatoprotective action was disquisitive in the D-GalN/LPS-induced acute liver injury (ALI) mouse model. The characterizations of OBB-ASDs indicated that the crystalline form of OBB active pharmaceutical ingredients (API) was changed into an amorphous form in OBB-ASDs. More importantly, OBB-ASDs showed a higher bioavailability than OBB API. In addition, OBB-ASDs treatment restored abnormal histopathological changes, improved liver functions, and relieved hepatic inflammatory mediators and oxidative stress in ALI mice. The spray drying techniques produced an amorphous form of OBB, which could significantly enhance the bioavailability and exhibit excellent hepatoprotective effects, indicating that the OBB-ASDs can exhibit further potential in hepatoprotective drug delivery systems. Our results provide guidance for improving the bioavailability and pharmacological activities of other compounds, especially insoluble natural compounds. Meanwhile, the successful development of OBB-ASDs could shed new light on the research process of poorly soluble medicine.

Utilizing the allyl-terminated copolymer methoxy(poly(ethylene glycol))-block-poly(jasmine lactone) in the development of amorphous solid dispersions: A comparative study of functionalized and non-functionalized polymer

Molecular interactions are crucial to stabilize amorphous drugs in amorphous solid dispersions (ASDs). Most polymers, however, have only a limited ability to form strong molecular interactions with drugs. Polymers tailored to fit the physicochemical properties of the drug molecule to be incorporated, for instance by allowing the incorporation of specific functional groups, would be highly sought-for in this regard. For this purpose, the novel allyl-terminated polymer methoxy(polyethylene glycol)-block-poly(jasmine lactone) (mPEG-b-PJL) has been synthesized and functionalized to potentially enhance specific drug-polymer interactions. This study investigated the use of mPEG-b-PJL in ASDs, using carvedilol (CAR), a weakly basic model drug. The findings revealed that the acidic functionalized form of the polymer (mPEG-b-PJL-COOH) indeed established stronger molecular interactions with CAR compared to its non-functionalized counterpart mPEG-b-PJL. Evaluations on polymer effectiveness in forming ASDs demonstrated that mPEG-b-PJL-COOH outperformed its non-functionalized counterpart in miscibility, drug loading ability, and stability, inferred from reduced molecular mobility. However, dissolution tests indicated that ASDs with mPEG-b-PJL-COOH did not significantly improve the dissolution behaviour compared to amorphous CAR alone, despite potential solubility enhancement through micelle formation. Overall, this study confirms the potential of functionalized polymers in ASD formulations, while the challenge of improving dissolution performance in these ASDs remains an area of further development.

Poly(vinylpyridine-co-vinylpyridine N-oxide) Excipients Mediate Rapid Dissolution and Sustained Supersaturation of Posaconazole Amorphous Solid Dispersions

The chemical structure of excipients molecularly mixed in an amorphous solid dispersion (ASD) has a significant impact on properties of the ASD including dissolution behavior, physical stability, and bioavailability. Polymers used in ASDs require a balance between hydrophobic and hydrophilic functionalities to ensure rapid dissolution of the amorphous dispersion as well as sustained supersaturation of the drug in solution. This work demonstrates the use of postpolymerization functionalization of poly(vinylpyridine) excipients to elucidate the impact of polymer properties on the dissolution behavior of amorphous dispersions containing posaconazole. It was found that N-oxidation of pyridine functionalities increased the solubility of poly(vinylpyridine) derivatives in neutral aqueous conditions and allowed for nanoparticle formation which supplied posaconazole into solution at concentrations exceeding those achieved by more conventional excipients such as hydroxypropyl methylcellulose acetate succinate (HPMCAS) or Eudragit E PO. By leveraging these functional modifications of the parent poly(vinylpyridine) excipient to increase polymer hydrophilicity and minimize the effect of polymer on pH, a new polymeric excipient was optimized for rapid dissolution and supersaturation maintenance for a model compound.

The Impact of Various Poly(vinylpyrrolidone) Polymers on the Crystallization Process of Metronidazole

In this paper, we propose one-step synthetic strategies for obtaining well-defined linear and star-shaped polyvinylpyrrolidone (linPVP and starPVP). The produced macromolecules and a commercial PVP K30 with linear topology were investigated as potential matrices for suppressing metronidazole (MTZ) crystallization. Interestingly, during the formation of binary mixtures (BMs) containing different polymers and MTZ, we found that linear PVPs exhibit maximum miscibility with the drug at a 50:50 weight ratio (w/w), while the star-shaped polymer mixes with MTZ even at a 30:70 w/w. To explain these observations, comprehensive studies of MTZ-PVP formulations with various contents of both components were performed using Fourier-transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction. The obtained results clearly showed that the polymer's topology plays a significant role in the type of interactions occurring between the matrix and MTZ. Additionally, we established that for MTZ-PVP 50:50 and 75:25 w/w BMs, linear polymers have the most substantial impact on inhibiting the crystallization of API. The star-shaped macromolecule turned out to be the least effective in stabilizing amorphous MTZ at these polymer concentrations. Nevertheless, long-term structural investigations of the MTZ-starPVP 30:70 w/w system (which is not achievable for linear PVPs) demonstrated its complete amorphousness for over one month.

The Implications of Drug-Polymer Interactions on the Physical Stability of Amorphous Solid Dispersions

Amorphous solid dispersions (ASDs) are a formulation and development strategy that can be used to increase the apparent aqueous solubility of poorly water-soluble drugs. Their implementation, however, can be hindered by destabilization of the amorphous form, as the drug recrystallizes from its metastable state. Factors such as the drug-polymer solubility, miscibility, mobility, and nucleation/crystal growth rates are all known to impact the physical stability of an ASD. Non-covalent interactions (NCI) between the drug and polymer have also been widely reported to influence product shelf-life. In this review, the relationship between thermodynamic/kinetic factors and adhesive NCI is assessed. Various types of NCIs reported to stabilize ASDs are described, and their role in affecting physical stability is examined. Finally, NCIs that have not yet been widely explored in ASD formulations, but may potentially impact their physical stability are also briefly described. This review aims to stimulate further theoretical and practical exploration of various NCIs and their applications in ASD formulations in the future.

Enhanced Oral Bioavailability of Rivaroxaban-Loaded Microspheres by Optimizing the Polymer and Surfactant Based on Molecular Interaction Mechanisms

This study aimed to develop microspheres using water-soluble carriers and surfactants to improve the solubility, dissolution, and oral bioavailability of rivaroxaban (RXB). RXB-loaded microspheres with optimal carrier (poly(vinylpyrrolidone) K30, PVP) and surfactant (sodium lauryl sulfate (SLS)) ratios were prepared. 1H NMR and Fourier transform infrared (FTIR) analyses showed that drug-excipient and excipient-excipient interactions affected RXB solubility, dissolution, and oral absorption. Therefore, molecular interactions between RXB, PVP, and SLS played an important role in improving RXB solubility, dissolution, and oral bioavailability. Formulations IV and VIII, containing optimized RXB/PVP/SLS ratios (1:0.25:2 and 1:1:2, w/w/w), had significantly improved solubility by approximately 160- and 86-fold, respectively, compared to RXB powder, with the final dissolution rates improved by approximately 4.5- and 3.4-fold, respectively, compared to those of RXB powder at 120 min. Moreover, the oral bioavailability of RXB was improved by 2.4- and 1.7-fold, respectively, compared to that of RXB powder. Formulation IV showed the highest improvement in oral bioavailability compared to RXB powder (AUC, 2400.8 ± 237.1 vs 1002.0 ± 82.3 h·ng/mL). Finally, the microspheres developed in this study successfully improved the solubility, dissolution rate, and bioavailability of RXB, suggesting that formulation optimization with the optimal drug-to-excipient ratio can lead to successful formulation development.

Effect of Drug-Polymer Interaction in Amorphous Solid Dispersion on the Physical Stability and Dissolution of Drugs: The Case of Alpha-Mangostin

Improving drug solubility is necessary for formulations of poorly water-soluble drugs, especially for oral administration. Amorphous solid dispersions (ASDs) are widely used in the pharmaceutical industry to improve the physical stability and solubility of drugs. Therefore, this study aims to characterize interaction between a drug and polymer in ASD, as well as evaluate the impact on the physical stability and dissolution of alpha-mangostin (AM). AM was used as a model of a poorly water-soluble drug, while polyvinylpyrrolidone (PVP) and eudragit were used as polymers. The amorphization of AM-eudragit and AM-PVP was confirmed as having a halo pattern with powder X-ray diffraction measurements and the absence of an AM melting peak in the differential scanning calorimetry (DSC) curve. The solubility of amorphous AM increased in the presence of either eudragit or PVP due to amorphization and interactions of AM-polymer. Furthermore, FT-IR spectroscopy and in silico studies revealed hydrogen bond interactions between the carbonyl group of AM and the proton of eudragit as well as PVP. AM-eudragit with a ratio of 1:1 recrystallized after 7 days of storage at 25 °C and 90% RH, while the AM-PVP 1:4 and 1:10 samples retained the X-ray halo patterns, even under humid conditions. In a dissolution test, the presence of polymer in ASD significantly improved the dissolution profile due to the intermolecular interaction of AM-polymer. AM-eudragit 1:4 maintained AM supersaturation for a longer time compared to the 1:1 sample. However, a high supersaturation was not achieved in AM-PVP 1:10 due to the formation of large agglomerations, leading to a slow dissolution rate. Based on the results, interaction of AM-polymer in ASD can significantly improve the pharmaceutical properties of AM including the physical stability and dissolution.

Carboxymethyl starch as a solid dispersion carrier to enhance the dissolution and bioavailability of piperine and 18β-glycyrrhetinic acid

OBJECTIVE

To investigate the applicability of carboxymethyl starch (CMS) as a carrier to prepare solid dispersions (SDs) of piperine (PIP) and 18β-glycyrrhetinic acid (β-GA) (PIP-CMS and β-GA-CMS SDs) and to explore the influence of drug properties on carrier selection.

SIGNIFICANCE

The low oral bioavailability of natural therapeutic molecules, including PIP and β-GA, severely restricts their pharmaceutical applications. Moreover, CMS, a natural polymer, is rarely reported as a carrier for SDs.

METHODS

PIP-CMS and β-GA-CMS SDs were prepared using the solvent evaporation method. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) were used for formulation characterization. Additionally, drug release characteristics were investigated.

RESULTS

In vitro dissolution studies showed that the dissolutions of PIP-CMS and β-GA-CMS SDs were 1.90-2.04 and 1.97-2.22 times higher than pure PIP and β-GA, respectively, at a drug:polymer ratio of 1:6. DSC, XRPD, FT-IR, and SEM analyses confirmed the formation of SDs in their amorphous states. Significant improvements in C_max and AUC_0-24 h of PIP-CMS and β-GA-CMS SDs (17.51 ± 8.15 μg/mL and 210.28 ± 117.13 μg·h/mL, respectively) and (32.17 ± 9.45 μg/mL and 165.36 ± 38.75 μg·h/mL, respectively) were observed in the pharmacokinetic study. Compared with weakly acidic β-GA, loading weakly basic PIP seemed to have a profound effect on stability through intermolecular forces.

CONCLUSIONS

Our findings showed CMS could be a promising carrier for SDs, and loading weakly basic drug may be more suitable, especially in binary SDs system.

Improvement of Oral Absorption of Poorly Water-Soluble Drugs by Solid Dispersions with Amphiphilic Phospholipid Polymer

Solid dispersions are one of methods for solubilizing water-insoluble drugs. To enhance the bioavailability, maintenance of the supersaturated state and absorption of the dissolved drug in the gastrointestinal tract are important. We designed and synthesized amphiphilic 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymers as carriers for solid dispersions and evaluated the dissolution behavior in test solutions with different pH and additives. Solid dispersion of troglitazone with amphiphilic MPC copolymers having both aromatic rings and urethane bonds in the side chains showed rapid dissolution and excellent supersaturation maintenance. It was indicated that the balance between the interactions with drug molecules and the water affinity of the polymer should be considered when carriers for solid dispersions are designed. In addition, cell membrane permeability of the solid dispersion with the amphiphilic MPC copolymer was evaluated by the Dissolution / Permeation system, which consists of two liquid chambers and a monolayer of epithelial cells that mimics the intestinal dissolution and permeation process. Further, blood concentration of the drug when solid dispersions were orally administered in mice was also evaluated. The cell membrane permeability and oral absorbability were significantly improved, compared to the solid dispersions with poly(N-vinylpyrrolidone) and suspension or solution of crystalline troglitazone.

Designing synergistic crystallization inhibitors: Bile salt derivatives of cellulose with enhanced hydrophilicity

Crystallization inhibitors in amorphous solid dispersions (ASD) enable metastable supersaturated drug solutions that persist for a physiologically relevant time. Olefin cross-metathesis (CM) has successfully provided multifunctional cellulose-based derivatives as candidate ASD matrix polymers. In proof of concept studies, we prepared hydrophobic bile salt/cellulose adducts by CM with naturally occurring bile salts. We hypothesized that increased hydrophilicity would enhance the ability of these conjugates to maximize bioactive supersaturation. Their selective preparation presents a significant synthetic challenge, given polysaccharide reactivity and polysaccharide and bile salt complexity. We prepared such derivatives using a more hydrophilic hydroxypropyl cellulose (HPC) backbone, employing a pent-4-enyl tether (Pen) for appending bile acids. We probed structure-property relationships by varying the nature and degree of substitution of the bile acid substituent (lithocholic or deoxycholic acid). These conjugates are indeed synergistic inhibitors, as demonstrated with the fast-crystallizing prostate cancer drug, enzalutamide. The lithocholic acid methyl ester derivative, AcrMLC-PenHHPCPen (0.64), increased induction time 68 fold vs. drug alone.

Effects of Polymers on the Drug Solubility and Dissolution Enhancement of Poorly Water-Soluble Rivaroxaban

The purpose of this study was to investigate the efficacy of hydrophilic polymers in a solid dispersion formulation in improving the solubility and dissolution rate of rivaroxaban (RXB), a poorly soluble drug. The developed solid dispersion consisted of two components, a drug and a polymer, and the drug was dispersed as amorphous particles in a polymer matrix using the spray drying method. Polymeric solid dispersions were evaluated using solubility tests, in vitro dissolution tests, powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and particle size distribution analysis. To maximize physical stability against crystallization and improve the solubility and dissolution of RXB, it is important to select the appropriate polymer type and the optimal ratio of the polymer to the drug. The optimized polyvinyl alcohol (PVA)-based (1/0.5, w/w) and gelatin-based (1/5, w/w) solid dispersion formulations showed 6.3 and 3.6 times higher drug solubilities than pure RXB powder, respectively, and the final dissolution rate was improved by approximately 1.5 times. Scanning electron microscopy and particle size distribution analyses confirmed that the gelatin-based solid dispersion was smaller and more spherical than the PVA-based solid dispersion, suggesting that the gelatin-based solid dispersion had a faster initial dissolution rate. Differential scanning calorimetry and powder X-ray diffraction analyses confirmed that RXB had successfully changed from a crystalline form to an amorphous form, contributing to the improvement in its solubility and dissolution rate. This study provides a strategy for selecting suitable polymers for the development of amorphous polymer solid dispersions that can overcome precipitation during dissolution and stabilization of the amorphous state. In addition, the selected polymer solid dispersion improved the drug solubility and dissolution rate of RXB, a poorly soluble drug, and may be used as a promising drug delivery system.

The Effect of Various Poly (N-vinylpyrrolidone) (PVP) Polymers on the Crystallization of Flutamide

In this study, several experimental techniques were applied to probe thermal properties, molecular dynamics, crystallization kinetics and intermolecular interactions in binary mixtures (BMs) composed of flutamide (FL) and various poly(N-vinylpyrrolidone) (PVP) polymers, including a commercial product and, importantly, samples obtained from high-pressure syntheses, which differ in microstructure (defined by the tacticity of the macromolecule) from the commercial PVP. Differential Scanning Calorimetry (DSC) studies revealed a particularly large difference between the glass transition temperature (Tg) of FL+PVPsynth. mixtures with 10 and 30 wt% of the excipient. In the case of the FL+PVPcomm. system, this effect was significantly lower. Such unexpected findings for the former mixtures were strictly connected to the variation of the microstructure of the polymer. Moreover, combined DSC and dielectric measurements showed that the onset of FL crystallization is significantly suppressed in the BM composed of the synthesized polymers. Further non-isothermal DSC investigations carried out on various FL+10 wt% PVP mixtures revealed a slowing down of FL crystallization in all FL-based systems (the best inhibitor of this process was PVP Mn = 190 kg/mol). Our research indicated a significant contribution of the microstructure of the polymer on the physical stability of the pharmaceutical-an issue completely overlooked in the literature.

Pharmaceutical profiling and molecular dynamics simulations reveal crystallization effects in amorphous formulations

Robust and reliable in vivo performance of medicines based on amorphous solid dispersions (ASDs) depend on maintenance of physical stability and efficient supersaturation. However, molecular drivers of these two kinetic processes are poorly understood. Here we used molecular dynamics (MD) simulations coupled with experimental assessments to explore supersaturation, nucleation, and crystal growth. The effect of drug loading on physical stability and supersaturation potential was highly drug specific. Storage under humid conditions influenced crystallization, but also resulted in morphological changes and particle fusion. This led to increased particle size, which significantly reduced dissolution rate. MD simulations identified the importance of nano-compartmentalization in the crystallization rate of the ASDs. Nucleation during storage did not inherently compromise the ASD. Rather, the poorer performance resulted from a combination of properties of the compound, nanostructures formed in the formulation, and crystallization.

Sensitive Tumor Cell Line for Annonaceous Acetogenins and High Therapeutic Efficacy at a Low Dose for Choriocarcinoma Therapy

Annonaceous acetogenins (ACGs) have attracted much attention because of excellent antitumor activity. However, the lack of selectivity and the accompanying serious toxicity have eventually prevented ACGs from entering clinical application. To decrease the side effects of ACGs, the cytotoxicity of ACGs on 10 types of tumor cell lines was investigated by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) test to identify one that was very sensitive to ACGs. Meanwhile, ACGs nanoparticles (ACGs-NPs) were prepared using poloxamer 188 (P188) as an excipient so as to solve the problem of poor solubility and the in vivo delivery of ACGs. ACG-NPs were 163.9±2.5 nm in diameter, negatively charged, and spherical with a high drug loading content (DLC) of 44.9±1.2%. MTS assays demonstrated that ACGs had strong cytotoxicity against JEG-3, HeLa, SiHa, MCF-7, A375, A2058, A875, U-118MG, LN- 229, and A431 cells, among which JEG-3 cell line was extremely sensitive to ACGs with a 50% inhibitory concentration (IC50) value of 0.26 ng/mL, a very encouraging discovery. ACGs-NPs demonstrated very good dose-dependent antitumor efficacy in a broad range of 45?1200 μg/kg on JEG-3 tumor-bearing mice. At a very low dose (1200 μg/kg), ACGs-NPs achieved a high tumor inhibition rate (TIR) of 77.6% through oral administration, displaying a significant advantage over paclitaxel (PTX) injections that are currently used as first-line anti-choriocarcinoma drugs. In the acute toxicity study, the half lethal dose (LD50) of ACGs-NPs was 135.5 mg/kg, which was over 100 times as of the effective antitumor dose, indicating good safety of ACGs-NPs. ACGs-NPs show promise as a new type of and potent anti-choriocarcinoma drug in the future.

Polyelectrolyte Matrices in the Modulation of Intermolecular Electrostatic Interactions for Amorphous Solid Dispersions: A Comprehensive Review

Polyelectrolyte polymers have been widely used in the pharmaceutical field as excipients to facilitate various drug delivery systems. Polyelectrolytes have been used to modulate the electrostatic environment and enhance favorable interactions between the drug and the polymer in amorphous solid dispersions (ASDs) prepared mainly by hot-melt extrusion. Polyelectrolytes have been used alone, or in combination with nonionic polymers as interpolyelectrolyte complexes, or after the addition of small molecular additives. They were found to enhance physical stability by favoring stabilizing intermolecular interactions, as well as to exert an antiplasticizing effect. Moreover, they not only enhance drug dissolution, but they have also been used for maintaining supersaturation, especially in the case of weakly basic drugs that tend to precipitate in the intestine. Additional uses include controlled and/or targeted drug release with enhanced physical stability and ease of preparation via novel continuous processes. Polyelectrolyte matrices, used along with scalable manufacturing methods in accordance with green chemistry principles, emerge as an attractive viable alternative for the preparation of ASDs with improved physical stability and biopharmaceutic performance.

Application of Polymers as a Tool in Crystallization-A Review

The application of polymers as a tool in the crystallization process is gaining more and more interest among the scientific community. According to Web of Science statistics the number of papers dealing with “Polymer induced crystallization” increased from 2 in 1990 to 436 in 2020, and for “Polymer controlled crystallization”—from 4 in 1990 to 344 in 2020. This is clear evidence that both topics are vivid, attractive and intensively investigated nowadays. Efficient control of crystallization and crystal properties still represents a bottleneck in the manufacturing of crystalline materials ranging from pigments, antiscalants, nanoporous materials and pharmaceuticals to semiconductor particles. However, a rapid development in precise and reliable measuring methods and techniques would enable one to better describe phenomena involved, to formulate theoretical models, and probably most importantly, to develop practical indications for how to appropriately lead many important processes in the industry. It is clearly visible at the first glance through a number of representative papers in the area, that many of them are preoccupied with the testing and production of pharmaceuticals, while the rest are addressed to new crystalline materials, renewable energy, water and wastewater technology and other branches of industry where the crystallization process takes place. In this work, authors gathered and briefly discuss over 100 papers, published in leading scientific periodicals, devoted to the influence of polymers on crystallizing solutions.

Impact of Drug-Polymer Intermolecular Interactions on Dissolution Performance of Copovidone-Based Amorphous Solid Dispersions

For poorly soluble drugs formulated as amorphous solid dispersions (ASDs), fast and complete release with the generation of drug-rich colloidal particles is beneficial for optimizing drug absorption. However, this ideal dissolution profile can only be achieved when the drug releases at the same normalized rate as the polymer, also known as congruent release. This phenomenon only occurs when the drug loading (DL) is below a certain value. The maximal DL at which congruent release occurs is defined as the limit of congruency (LoC). The purpose of this study was to investigate the relationship between drug chemical structure and LoC for PVPVA-based ASDs. The compounds investigated shared a common scaffold substituted with different functional groups, capable of forming hydrogen bonds only, halogen bonds only, both hydrogen and halogen bonds, or nonspecific interactions only with the polymer. Intermolecular interactions were studied and confirmed by X-ray photoelectron spectroscopy and infrared spectroscopy. The release rates of ASDs with different DLs were investigated using surface area normalized dissolution. ASDs with hydrogen bond formation between the drug and polymer had lower LoCs, while compounds that were only able to form halogen bonds or nonspecific interactions with the polymer achieved considerably higher LoCs. This study highlights the impact of different types of drug-polymer interactions on ASD dissolution performance, providing insights into the role of drug and polymer chemical structures on the LoC and ASD performance in general.

Effect of Chemical Penetration Enhancer-Adhesive Interaction on Drug Release from Transdermal Patch: Mechanism Study Based on FT-IR Spectroscopy, 13C NMR Spectroscopy, and Molecular Simulation

Chemical penetration enhancers (CPEs) are commonly added into transdermal patches to impart improved skin permeation of drug. However, significant unexplained variability in drug release kinetics in transdermal patches is possible as a result of the addition of CPEs; investigations into the underlying mechanisms are still limited. In the present study, a diverse set of CPEs was employed to draw broad conclusions. Solubility parameters of CPEs and acrylate pressure-sensitive adhesive were calculated by molecular dynamics simulation and Fedors group contribution method to evaluate drug-adhesive miscibility. CPE-adhesive interaction was characterized by FT-IR study, ¹³C NMR spectroscopy, and molecular docking simulation. Results showed that release enhancement ratio (ER_R) of CPEs for zolmitriptan was rank ordered as isopropyl myristate > azone > Plurol Oleique^® CC497 > Span^® 80 > N-methylpyrrolidone > Transcutol^® P. It was found that solubility parameter difference (Δδ) between CPE and adhesive was negatively related with ER_R. It was proved that hydrogen bonding between CPE and adhesive would increase drug release rate, but only if the CPE showed good miscibility with adhesive. CPE like isopropyl myristate, which had good miscibility with adhesive, could decrease drug-adhesive interaction leading to the release of drug from adhesive.

Influence of Plasdone™ S630 Ultra-an Improved Copovidone on the Processability and Oxidative Degradation of Quetiapine Fumarate Amorphous Solid Dispersions Prepared via Hot-Melt Extrusion Technique

In a formulation, traces of peroxides in copovidone can impact the stability of drug substances that are prone to oxidation. The present study aimed to investigate the impact of peroxides in novel Plasdone™ S630 Ultra and compare it with regular Plasdone™ S630 on the oxidative degradation of quetiapine fumarate amorphous solid dispersions prepared via hot-melt extrusion technique. The miscibility of copovidones with drug was determined using the Hansen solubility parameter, and the results indicated a miscible drug-polymer system. Melt viscosity as a function of temperature was determined for the drug-polymer physical mixture to identify the suitable hot-melt extrusion processing temperature. The binary drug and polymer (30:70 weight ratio) amorphous solid dispersions were prepared at a processing temperature of 160°C. Differential scanning calorimetry and Fourier transform infrared spectroscopy studies of amorphous solid dispersions revealed the formation of a single-phase amorphous system with intermolecular hydrogen bonding between the drug and polymer. The milled extrudates were compressed into tablets by using extragranular components and evaluated for tabletability. Stability studies of the milled extrudates and tablet formulations were performed to monitor the oxidative degradation impurity (N-oxide). The N-oxide impurity levels in the quetiapine fumarate - Plasdone™ S630 Ultra milled extrudates and tablet formulations were reduced by 2- and 3-folds, respectively, compared to those in quetiapine fumarate - Plasdone™ S630. The reduced oxidative degradation and improved hot-melt extrusion processability of Plasdone™ S630 Ultra make it a better choice for oxidation-labile drugs over Plasdone™ S630 copovidone.

Improved in vitro and in vivo properties of telmisartan in the co-amorphous system with hydrochlorothiazide: A potential drug-drug interaction mechanism prediction

The aim of this study is to improve in vitro and in vivo properties of an antihypertensive poorly soluble drug Telmisartan (TEL) by co-amorphization with a pharmacologically relevant drug Hydrochlorothiazide (HCT), and to improve the stability of single amorphous drugs. Herein, TEL-HCT co-amorphous systems (CAMs) (1:1, 2:3, 1:2, 1:3) were prepared by solvent evaporation. The apparent solubility and the dissolution of TEL in the TEL-HCT CAM (1:3) were increased by 79 times and 10 times compared to crystalline TEL, which showed the optimal properties. C_max and AUC_0-48h value of TEL-HCT CAM (1:3) were 10-fold and 3-fold as the crystalline state. Moreover, TEL-HCT CAM (1:3) remained stable in 60 °C, 0 % RH (30 days), 40 °C, 75 % RH (90 days) and 25 °C, 0 % RH (180 days). Positive ΔT_gs were observed in all CAMs, suggesting the existence of potential intermolecular force. Fourier Transform-Infrared and Raman spectra were used to further prove the drug-drug interaction and predict potential mechanisms. Therefore, in the strategy of combined medication, CAM provides a promising way to transfer drugs with poor properties into systems with enhanced dissolution, greater bioavailability, and stabilized amorphous state, which has been proven in this study.

Chemical Structural Effects of Amphipathic and Water-soluble Phospholipid Polymers on Formulation of Solid Dispersions

For the polymeric carriers of solid dispersions, it is important that carriers themselves dissolve quickly and maintain the supersaturated state of amorphous drugs during their dissolution period to improve bioavailability. Amphipathic 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers can be dissolved in water, owing to the extremely high hydrophilicity of the MPC units, and are used as an ideal feeder for drug molecules to form aggregates in aqueous conditions. We synthesized amphipathic MPC copolymers with different hydrophobic side chains and molar ratios of MPC units, and evaluated the effect of the polymers on dissolution rate and supersaturation maintenance of solid dispersions of indomethacin. In most of the water-soluble amphipathic MPC copolymers, "spring-parachute"-like dissolution behavior was observed, where the drug initially became supersaturated followed by slow precipitation. In particular, MPC copolymers with aromatic rings in their side chains or polymers with a high percentage of hydrophobic units remained in a supersaturated state for a longer period. In contrast, urethane groups, which form hydrogen bonds with drug molecules, could also interact with water and were not conducive to maintaining supersaturation. In addition, water solubility of the polymer is important for rapid dissolution.

Characterization of Amorphous Solid Dispersions and Identification of Low Levels of Crystallinity by Transmission Electron Microscopy

Amorphous solid dispersions (ASDs) are used to increase the solubility of oral medicines by kinetically stabilizing the more soluble amorphous phase of an active pharmaceutical ingredient with a suitable amorphous polymer. Low levels of a crystalline material in an ASD can negatively impact the desired dissolution properties of the drug. Characterization techniques such as powder X-ray diffraction (pXRD), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR) are often used to detect and measure any crystallinity within ASDs. These techniques are unable to detect or quantify very low levels because they have limits of detection typically in the order of 1-5%. Herein, an ASD of felodipine (FEL) and polyvinylpyrrolidone/vinyl acetate copolymer (PVP/VA) prepared via a hot melt extrusion (HME) in a mass ratio of 30:70 was characterized using a range of techniques. No signs of residual crystallinity were found by pXRD, DSC, or FTIR. However, transmission electron microscopy (TEM) did identify two areas containing crystals at the edges of milled particles from a total of 55 examined. Both crystalline areas contained Cl Kα X-ray peaks when measured by energy-dispersive X-ray spectroscopy, confirming the presence of FEL (due to the presence of Cl atoms in FEL and not in PVP/VA). Further analysis was carried out by TEM using conical dark field (DF) imaging of a HME ASD of 50:50 FEL-PVP/VA to provide insights into the recrystallization process that occurs at the edges of particles during accelerated ageing conditions in an atmosphere of 75% relative humidity. Multiple metastable polymorphs of recrystallized FEL could be identified by selected area electron diffraction (SAED), predominately form II and the more stable form I. Conical DF imaging was also successful in spatially resolving and sizing crystals. This work highlights the potential for TEM-based techniques to improve the limit of detection of crystallinity in ASDs, while also providing insights into transformation pathways by identifying the location, size, and form of any crystallization that might occur on storage. This opens up the possibility of providing an enhanced understanding of a drug product's stability and performance.

How can we improve the physical stability of co-amorphous system containing flutamide and bicalutamide? The case of ternary amorphous solid dispersions

The article describes the preparation and characterization of binary mixtures of two antiandrogens used in prostate cancer treatment, i.e. flutamide (FL) and bicalutamide (BIC), as well as their ternary mixtures with either poly(methyl methacrylate-co-ethyl acrylate) (MMA/EA) or polyvinylpyrrolidone (PVP). The samples were converted into amorphous form to improve their water solubility and dissolution rate. Broadband dielectric spectroscopy and differential scanning calorimetry revealed that FL-BIC (65%) (w/w) does not tend to crystallize from the supercooled liquid state. We made the assumption that the drug-to-drug weight ratio should be maintained as in the case of monotherapy so we decided to investigate the system containing FL and BIC in 15:1 (w/w) ratio with 30% additive of polymers as stabilizers. Our research has shown that only in the case of the FL-BIC-PVP mixture the crystallization has been completely inhibited, both in glassy and supercooled liquid state, which was confirmed by X-ray diffraction studies. In addition, we performed solubility and dissolution rate tests, which showed a significant improvement in solubility of ternary system as compared to its crystalline counterpart. Enhanced physical stability and water solubility of the amorphous ternary system makes it promising for further studies.

Impact of the Chain Length and Topology of the Acetylated Oligosaccharide on the Crystallization Tendency of Naproxen from Amorphous Binary Mixtures

The impact of the chain length or dispersity of polymers in controlling the crystallization of amorphous active pharmaceutical ingredients (APIs) has been discussed for a long time. However, because of the weak control of these parameters in the majority of macromolecules used in pharmaceutical formulations, the abovementioned topic is poorly understood. Herein, four acetylated oligosaccharides, maltose (acMAL), raffinose (acRAF), stachyose (acSTA), and α-cyclodextrin (ac-α-CD) of growing chain lengths and different topologies (linear vs cyclic), mimicking the growing backbone of the polymer, were selected to probe the influence of these structural factors on the crystallization of naproxen (NAP)—an API that does not vitrify regardless of the cooling rate applied in our experiment. It was found that in equimolar systems composed of NAP and linear acetylated oligosaccharides, the progress and activation barrier for crystallization are dependent on the molecular weight of the excipient despite the fact that results of Fourier transform infrared studies indicated that there is no difference in the interaction pattern between measured samples. On the other hand, complementary dielectric, calorimetric, and X-ray diffraction data clearly demonstrated that NAP mixed with ac-α-CD (cyclic saccharide) does not tend to crystallize even in the system with a much higher content of APIs. To explain this interesting finding, we have carried out further density functional theory computations, which revealed that incorporation of NAP into the cavity of ac-α-CD is hardly possible because this state is of much higher energy (up to 80 kJ/mol) with respect to the one where the API is located outside of the saccharide torus. Hence, although at the moment, it is very difficult to explain the much stronger impact of the cyclic saccharide on the suppression of crystallization and enhanced stability of NAP with respect to the linear carbohydrates, our studies clearly showed that the chain length and the topology of the excipient play a significant role in controlling the crystallization of this API.

Selective Laser Sintering 3-Dimensional Printing as a Single Step Process to Prepare Amorphous Solid Dispersion Dosage Forms for Improved Solubility and Dissolution Rate

This study reports the development of ritonavir-copovidone amorphous solid dispersions (ASDs) and dosage forms thereof using selective laser sintering (SLS) 3-dimensional (3-D) printing in a single step, circumventing the post-processing steps required in common techniques employed to make ASDs. For this study, different drug loads of ritonavir with copovidone were processed at varying processing conditions to understand the impact, range, and correlation of these parameters for successful ASD formation. Further, ASDs characterized using conventional and advanced solid-state techniques including wide-angle X-ray scattering (WAXS), solid-state nuclear magnetic resonance (ssNMR), revealed the full conversion of the crystalline drug to its amorphous form as a function of laser-assisted selective fusion in a layer-by-layer manner. It was observed that an optimum combination of the powder flow properties, surface temperature, chamber temperature, laser speed, and hatch spacing was crucial for successful ASD formation, any deviations resulted in print failures or only partial amorphous conversion. Moreover, a 21-fold increase in solubility was demonstrated by the SLS 3-D printed tablets. The results confirmed that SLS 3-D printing can be used as a single-step platform for creating ASD-based pharmaceutical dosage forms with a solubility advantage.

A novel amorphous solid dispersion based on drug-polymer complexation

Rafoxanide (RAF) is a poorly water-soluble drug that forms a complex with povidone K25 (PVP) in a cosolvent system containing acetone and an alkaline aqueous medium. This study aims to investigate the impact of RAF-PVP complexation on in vitro and in vivo release of RAF. We prepared two RAF amorphous solid dispersions (ASDs) spray-dried from these two cosolvents. The first is a complexation-based spray-drying using a 70% 0.1 N NaOH solution with 30% acetone. The second is a traditional spray-dried formulation containing 80% acetone and 20% ethanol. Evidence from multiple solid-state characterization techniques indicated that ASDs spray-dried using both methods were amorphous. However, RAF ASDs based on drug-polymer complexation in the feed solution demonstrated not only faster drug release during dissolution testing but also higher in vivo absorption in an animal model. The improved RAF release in the complexation-based ASD is due to (1) high energy state of RAF owing to the amorphous form, (2) high pH in the microenvironment due to the ionized state of RAF and residual sodium hydroxide, (3) increased apparent solubility of RAF results from RAF-PVP complexation in dissolution media and biological media, and (4) improved wettability.

Predictive identification of co-formers in co-amorphous systems

This work aims to understand the properties of co-formers that form co-amorphous pharmaceutical materials and to predict co-amorphous system formation. A partial least square - discriminant analysis (PLS-DA) was performed using known co-amorphous systems described by 36 variables based on the properties of the co-former and the binding energy of the system. The PLS-DA investigated the propensity to form co-amorphous material of the active pharmaceutical ingredients: mebendazole, carvedilol, indomethacin, simvastatin, carbamazepine and furosemide in combination with 20 amino acid co-formers. The variables that were found to favour the propensity to form co-amorphous systems appear to be a relatively large value for average molecular weight and the sum of the difference between hydrogen bond donors and hydrogen bond acceptors for both components, and a relatively small or negative value for excess enthalpy of mixing, excess enthalpy of hydrogen bonding and the difference in the Hansen parameter for hydrogen bonding of the coformer and the active pharmaceutical ingredient (API). To test the predictive power of this model, 29 potential co-formers were used to form either co-amorphous or crystalline two-component materials with mebendazole. Of these 29 two-component systems, the co-amorphous nature of a total of 26 materials was correctly predicted by the model, giving a predictive hit rate of 90 %.

Automation Potential of a New, Rapid, Microscopy-Based Method for Screening Drug-Polymer Solubility

For the pharmaceutical industry, the preformulation screening of the compatibility of drug and polymeric excipients can often be time-consuming because of the use of trial-and-error approaches. This is also the case for selecting highly effective polymeric excipients for forming molecular dispersions in order to improve the dissolution and subsequent bio-availability of a poorly soluble drug. Previously, we developed a new thermal imaging-based rapid screening method, thermal analysis by structure characterization (TASC), which can rapidly detect the melting point depression of a crystalline drug in the presence of a polymeric material. In this study, we used melting point depression as an indicator of drug solubility in a polymer and further explored the potential of using the TASC method to rapidly screen and identify polymers in which a drug is likely to have high solubility. Here, we used a data bank of 5 model drugs and 10 different pharmaceutical grade polymers to validate the screening potential of TASC. The data indicated that TASC could provide significant improvement in the screening speed and reduce the materials used without compromising the sensitivity of detection. It should be highlighted that the current method is a screening method rather than a method that provides absolute measurement of the degree of solubility of a drug in a polymer. The results of this study confirmed that the TASC results of each drug-polymer pair could be used in data matrices to indicate the presence of significant interaction and solubility of the drug in the polymer. This forms the foundation for automating the screening process using artificial intelligence.

Application of solid-state 13C relaxation time to prediction of the recrystallization inhibition strength of polymers on amorphous felodipine at low polymer loading

The potential for inhibiting recrystallization with Eudragit® L (EUD-L), hypromellose acetate succinate (HPMC-AS), and polyvinylpyrrolidone-co-vinylacetate (PVP-VA) on amorphous felodipine (FLD) at low polymer loading was investigated in this study. The physical stabilities of the FLD/polymer amorphous solid dispersions (ASDs) were investigated through storage at 40 °C. The HPMC-AS and PVP-VA strongly inhibited FLD recrystallization, although EUD-L did not effectively inhibit the FLD recrystallization. The rotating frame ¹H spin-lattice relaxation time (¹H-T_1ρ) measurement clarified that EUD-L was not well mixed with FLD in the ASD, which resulted in weak inhibition of recrystallization by EUD-L. In contrast, the HPMC-AS and PVP-VA were well mixed with the FLD in the ASDs. Solid-state ¹³C spin-lattice relaxation time (¹³C-T₁) measurements at 40 °C showed that the molecular mobility of the FLD was strongly suppressed when mixed with polymer. The reduction in the molecular mobility of FLD was in the following order, starting with the least impact: FLD/EUD-L ASD, FLD/HPMC-AS ASD, and FLD/PVP-VA ASD. FLD mobility at the storage temperature, evaluated by ¹³C-T₁, showed a good correlation with the physical stability of the amorphous FLD. The direct investigation of the molecular mobility of amorphous drugs at the storage temperature by solid-state NMR relaxation time measurement can be a useful tool in selecting the most effective crystallization inhibitor at low polymer loading.

The use of amphiphilic copolymer in the solid dispersion formulation of nimodipine to inhibit drug crystallization in the release media: Combining nano-drug delivery system with solid preparations

Solid dispersion is a widely used method to improve the dissolution and oral bioavailability of water-insoluble drugs. However, due to the strong hydrophobicity, the drug crystallization in the release media after drug dissolution and the resulted decreased drug absorption retards the use of solid dispersions. It is widely known that the amphiphilic copolymer can encapsulate the hydrophobic compounds and help form stable nano-dispersions in water. Inspired by this, we tried to formulate the solid dispersion of nimodipine by using amphipathic copolymer as one of the carriers. Concerning the solid dispersions, there are many important points involved in these formulations, such as the miscibility between the drug and the carriers, the storage stability of solid dispersions, the dissolution enhancement and so on. In this study, a systemic method is proposed. In details, the supersaturation test and the glass transition temperature (T_g) measurement to predict the crystallization inhibition, the ratios of different components and the storage stability, the interactions among the components were investigated in detail by nuclear magnetic resonance (¹H NMR) and isothermal titration calorimetry (ITC) and, the final dissolution and oral bioavailability enhancement. It was found that the amphiphilic copolymer used in the solid dispersion encouraged the formation the drug loading micelles in the release media and, finally, the problem of drug crystallization in the dissolution process was successfully solved.

How can we improve the physical stability of co-amorphous system containing flutamide and bicalutamide? The case of ternary amorphous solid dispersions

The article describes the preparation and characterization of binary mixtures of two antiandrogens used in prostate cancer treatment, i.e. flutamide (FL) and bicalutamide (BIC), as well as their ternary mixtures with either poly(methyl methacrylate-co-ethyl acrylate) (MMA/EA) or polyvinylpyrrolidone (PVP). The samples were converted into amorphous form to improve their water solubility and dissolution rate. Broadband dielectric spectroscopy and differential scanning calorimetry revealed that FL-BIC (65%) (w/w) does not tend to crystallize from the supercooled liquid state. We made the assumption that the drug-to-drug weight ratio should be maintained as in the case of monotherapy so we decided to investigate the system containing FL and BIC in 15:1 (w/w) ratio with 30% additive of polymers as stabilizers. Our research has shown that only in the case of the FL-BIC-PVP mixture the crystallization has been completely inhibited, both in glassy and supercooled liquid state, which was confirmed by X-ray diffraction studies. In addition, we performed solubility and dissolution rate tests, which showed a significant improvement in solubility of ternary system as compared to its crystalline counterpart. Enhanced physical stability and water solubility of the amorphous ternary system makes it promising for further studies.

Characterization of Amorphous Solid Dispersion of Pharmaceutical Compound with pH-Dependent Solubility Prepared by Continuous-Spray Granulator

A continuous-spray granulator (CTS-SGR) is a one-step granulation technology capable of using solutions or suspensions. The present research objectives were, (1) to reduce the manufacturing operations for solid dosage formulations, (2) to make amorphous solid dispersion (ASD) granules without pre-preparation of amorphous solids of active pharmaceutical ingredients (API), and (3) to characterize the obtained SGR granules by comprehensive pharmaceutical analysis. Rebamipide (RBM), a biopharmaceutical classification system class IV drug, that has low solubility or permeability in the stomach, was selected as a model compound. Five kind of granules with different concentrations of polyvinylpyrrolidone/vinyl acetate copolymer (PVP-VA) were prepared using a one-step SGR process. All of the SGR granules could be produced in amorphous or ASD form and their thermodynamic stability was very high because of high glass transition temperatures (>178 °C). They were unstable in 20 °C/75%RH; however, their stability was improved according to the proportion of polymer. The carboxy group of RBM was ionized in the granules and interactions appeared between RBM and PVP-VA, with the formation of an ASD confirmed and the solubility was enhanced compared with bulk RBM crystals. The SGR methodology has the possibility of contributing to process development in the pharmaceutical industry.

Stability and Bioavailability Enhancement of Telmisartan Ternary Solid Dispersions: the Synergistic Effect of Polymers and Drug-Polymer(s) Interactions

The purpose of this study was to investigate the synergistic effect of polymers and drug-polymer(s) interactions on the improved stability and bioavailability of telmisartan (TEL) ternary solid dispersions. As a water-insoluble drug, 40 and 160 mg doses of TEL tablets exhibited bioavailabilities of 42% and 58%, respectively. Through polymer screening, PVP K30 and/or Soluplus were selected and used at different concentrations to prepare TEL amorphous solid dispersions by solvent evaporation. Compared to pure TEL and TEL-PVP K30/Soluplus binary solid dispersions, TEL-PVP K30-Soluplus ternary solid dispersions demonstrated significant advantages, including higher dissolution (over 90% release at 60 min), better amorphous stability (physically stable in 90 days), and improved oral bioavailability (C_max of 5535.819 ± 325.67 ng/mL and t_max of 1 h). These advantages were related to the complementarity of PVP K30 and Soluplus on TEL. PVP K30 had a better activity to solubilize TEL and achieved a high TEL initial concentration in dissolution media. Simultaneously, the ability of Soluplus to assist in the maintenance of supersaturation played an important role. PVP K30 and Soluplus together inhibited crystallization of the drug at different stages. The existence and intensity of drug-polymer interactions were also determined by DSC (T_g determination) and FT-IR. At the molecular level, a hypothesis was also proposed that the enhancements resulted from the contribution of the synergistic effect between PVP K30 and Soluplus. These results suggested that two polymers, in a combination and via a synergistic effect, could further enhance the bioavailability and amorphous stability of ternary solid dispersions.

Effect of Polymer Hydrophobicity on the Stability of Amorphous Solid Dispersions and Supersaturated Solutions of a Hydrophobic Pharmaceutical

Amorphous solid dispersions of pharmaceuticals often show improved solubility over crystalline forms. However, the crystallization of amorphous solid dispersions during storage, or from elevated supersaturation once dissolved, compromise the solubility advantage of delivery in the amorphous phase. To combat this phenomenon, polymer additives are often included in solid dispersions to inhibit crystallization; however, the optimal properties for polymer to stabilize against crystallization are not fully understood, and furthermore, it is not known how inhibition of precipitation from solution is related to the propensity of a polymer to inhibit crystallization from the amorphous phase. Here, polymers of varied hydrophobicity are employed as crystallization inhibitors in supersaturated solutions and amorphous solid dispersions of the BCS Class II pharmaceutical ethenzamide to investigate the chemical features of polymer that lead to long-term stability for a hydrophobic pharmaceutical. A postpolymerization functionalization strategy was employed to alter the hydrophobicity of poly( N-hydroxyethyl acrylamide) without changing physical properties such as number-average chain length. It was found that supersaturation maintenance for ethenzamide is improved by increasing the hydrophobicity of dissolved polymer in aqueous solution. Furthermore, amorphous solid dispersions of ethenzamide containing a more hydrophobic polymer showed superior stability compared to those containing a less hydrophobic polymer. This trend of increasing polymer hydrophobicity leading to improved amorphous stability is interpreted by parsing the effects of water absorption in amorphous solid dispersions using intermolecular interaction strengths derived from global structural analysis. By comparing the structure-function relationships, which dictate stability in solution and amorphous solid dispersions, the effect of hydrophobicity can be broadly understood for the design of polymers to impart stability throughout the application of amorphous solid dispersions.