Drug Amorphous Solid Dispersions Based on Poly(vinyl Alcohol): Evaluating the Effect of Poly(propylene Succinate) as Plasticizer

Utilizing Drug Amorphous Solid Dispersions for the Preparation of Dronedarone per os Formulations

Dronedarone (DRN), an antiarrhythmic drug, exhibits potent pharmacological effects in the management of cardiac arrhythmias. Despite its therapeutic potential, DRN faces formulation challenges due to its low aqueous solubility. Hence, the present study is dedicated to the examination of amorphous solid dispersions (ASDs) as a strategic approach for enhancing the solubility of DRN. Initially, the glass forming ability (GFA) of API was assessed alongside its thermal degradation profile, and it was revealed that DRN is a stable glass former (GFA III compound) that remains thermally stable up to approximately 200 °C. Subsequently, five commonly used ASD matrix/carriers, i.e., hydroxypropyl methylcellulose (HPMC), povidone (PVP), copovidone (PVP/VA), Soluplus® (SOL), and Eudragit® E PO (EPO), were screened for the formation of a DRN-based ASD using film casting and solvent shift methods, along with miscibility evaluation measurements. SOL proved to be the most promising matrix/carrier among the others, and, hence, was used to prepare DRN ASDs via the melt-quench method. The physicochemical characterization of the prepared systems (via pXRD) revealed the complete amorphization of the API within the matrix/carrier, while the system was physically stable for at least three months after its preparation. In vitro release studies for the ASDs, conducted under non-sink conditions, revealed the sustained supersaturation of the drug for at least 8 h. Finally, the use of attenuated total reflectance (ATR) FTIR spectroscopy showed the formation of a strong molecular interaction between the drug molecules and SOL.

Hot Melt Extruded Posaconazole-Based Amorphous Solid Dispersions—The Effect of Different Types of Polymers

Four model polymers, representing (i) amorphous homopolymers (Kollidon K30, K30), (ii) amorphous heteropolymers (Kollidon VA64, KVA), (iii) semi-crystalline homopolymers (Parteck MXP, PXP), and (iv) semi-crystalline heteropolymers (Kollicoat IR, KIR), were examined for their effectiveness in creating posaconazole-based amorphous solid dispersions (ASDs). Posaconazole (POS) is a triazole antifungal drug that has activity against Candida and Aspergillus species, belonging to class II of the biopharmaceutics classification system (BCS). This means that this active pharmaceutical ingredient (API) is characterized by solubility-limited bioavailability. Thus, one of the aims of its formulation as an ASD was to improve its aqueous solubility. Investigations were performed into how polymers affected the following characteristics: melting point depression of the API, miscibility and homogeneity with POS, improvement of the amorphous API’s physical stability, melt viscosity (and associated with it, drug loading), extrudability, API content in the extrudate, long term physical stability of the amorphous POS in the binary drug–polymer system (in the form of the extrudate), solubility, and dissolution rate of hot melt extrusion (HME) systems. The obtained results led us to conclude that the physical stability of the POS-based system increases with the increasing amorphousness of the employed excipient. Copolymers, compared to homopolymers, display greater homogeneity of the investigated composition. However, the enhancement in aqueous solubility was significantly higher after utilizing the homopolymeric, compared to the copolymeric, excipients. Considering all of the investigated parameters, the most effective additive in the formation of a POS-based ASD is an amorphous homopolymer—K30.

API solubility in semi-crystalline polymer: Kinetic and thermodynamic phase behavior of PVA-based solid dispersions

The formulation of amorphous solid dispersions (ASDs) represents a promising strategy for improving the poor bioavailability of many active pharmaceutical ingredients (APIs). The objective of this study was to investigate and compare the long-term physical stability (LTPS) of polyvinyl alcohol (PVA)-based solid dispersions formulated via hot-melt extrusion (HME) with their respective API-PVA temperature-composition (T-C) phase diagram. Furthermore, the impact of API glass-forming ability (GFA) on the LTPS was evaluated through the selection of two APIs with contrasting GFA (i.e., indomethacin (IND; good GFA) and naproxen (NAP; poor GFA)). Even though the predicted solubility of both APIs in PVA was less than 1 wt% at T = 25 °C, IND remained fully amorphous in HME-formulated IND-PVA extrudates with initial API loadings of 50, 40, and 30 wt% after a 24-month storage period. Meanwhile, NAP recrystallized to a considerable degree in each analogous sample with an amorphous NAP content of 22.5-23.5 wt% remaining after a 12-month storage period. While the constructed T-C phase diagrams were still in agreement with their respective LTPS study, they did not account for the impact of water uptake as well as potential HME-induced effects on the extrudate glass-transition temperature. This work may serve as a useful reference point for researchers who are interested in determining the solubility of an API in a semi-crystalline polymer and the challenges therein.