Wilke SK, Benmore CJ, Menon V, Smith D, Byrn SR, Weber R. Molecular structure of ketoprofen-polyvinylpyrrolidone solid dispersions prepared by different amorphization methods.
RSC PHARMACEUTICS 2024;
1:121-131. [PMID:
38646594 PMCID:
PMC11024667 DOI:
10.1039/d3pm00038a]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/25/2024] [Indexed: 04/23/2024]
Abstract
Amorphous solid dispersions (ASDs) are a widely studied formulation approach for improving the bioavailability of poorly water-soluble pharmaceuticals. Yet, a complete understanding remains lacking for how specific processing methods may influence ASDs' molecular structure. We prepare ketoprofen/polyvinylpyrrolidone (KTP/PVP) ASDs, ranging from 0-75 wt% KTP, using five different amorphization techniques: melt quenching, rotary evaporation with vacuum drying, spray drying, and acoustic levitation with either a premixed solution or in situ mixing of separate co-sprayed solutions. The co-spray levitation approach enables on-demand compositional changes in a containerless processing environment, while requiring minimal pharmaceutical material (∼1 mg). The structure of all ASDs are then compared using high-energy X-ray total scattering. X-ray pair distribution functions are similar for most ASDs of a given composition (Rx = 0.4-2.5%), which is consistent with them having similar intramolecular structure. More notably, differences in the X-ray structure factors for the various amorphization routes indicate differing extents of molecular mixing, a direct indication of their relative stability against crystallization. Melt quenching, spray drying, and levitation of premixed solutions exhibit some degree of molecular mixing, while the co-sprayed levitation samples have molecular arrangements like those of KTP/PVP physical mixtures. These findings illustrate how X-ray total scattering can be used to benchmark amorphous forms prepared by different techniques.
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