Unexpected solvent impact in the crystallinity of praziquantel/poly (vinylpyrrolidone) formulations. A solubility, DSC and solid-state NMR study
The saturation solubility of PVP:PZQ physical mixtures (PMs) and solid dispersions (SDs) prepared from ethanol (E/E) or ethanol/water (E/W) by the solvent evaporation method at 1:1, 2:1 and 3:1 ratio (w/w) was determined. The presence of PVP improves the solubility of PZQ (0.31 ± 0.01 mg/mL). A maxi...
| Autores: | , , , , , , , , |
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| Tipo de documento: | artigo |
| Estado: | Versão publicada |
| Data de publicação: | 2016 |
| País: | Argentina |
| Recursos: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositório: | CONICET Digital (CONICET) |
| Idioma: | inglês |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/52670 |
| Acesso em linha: | http://hdl.handle.net/11336/52670 |
| Access Level: | Acceso aberto |
| Palavra-chave: | DSC PHARMACEUTICAL FORMULATIONS POLY(VINYLPYRROLIDONE) PRAZIQUANTEL SOLID-STATE NMR https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Resumo: | The saturation solubility of PVP:PZQ physical mixtures (PMs) and solid dispersions (SDs) prepared from ethanol (E/E) or ethanol/water (E/W) by the solvent evaporation method at 1:1, 2:1 and 3:1 ratio (w/w) was determined. The presence of PVP improves the solubility of PZQ (0.31 ± 0.01 mg/mL). A maximum of 1.29 ± 0.03 mg/mL of PZQ in solution was achieved for the 3:1 SD (E/E). The amount of PZQ in solution depends on the amount of polymer and on the preparation method. Solid-state NMR (ssNMR) and DSC were used to understand this behavior. Results show that PMs are a mixture of crystalline PZQ with the polymer, while SDs show different degrees of drug amorphization depending on the solvent used. For E/W SDs, PZQ exists in amorphous and crystalline states, with no clear correlation between the amount of crystalline PZQ and the amount of PVP. For E/E SDs, formulations with a higher percentage of PZQ are amorphous with the components miscible in domains larger than 3 nm (1H ssNMR relaxation measurements). Albeit its higher saturation solubility, the 3:1 E/E PVP:PZQ sample has a significant crystalline content, probably due to the water introduced by the polymer. High PVP content and small crystal size account for this result. |
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