FTIR Spectroscopic Study of Poly(Ethylene Glycol)–Nifedipine Dispersion Stability in Different Relative Humidities
Solid dispersion has shown to be a promising formulation strategy to enhance dissolution for hydrophobic drugs. However, solid dispersions are often thermodynamically unstable, there is a continuous interest in studying their stabilities. In this study, attenuated total reflectance Fourier transform...
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Veröffentlicht in: | Journal of pharmaceutical sciences 2015-01, Vol.104 (1), p.280-284 |
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Sprache: | eng |
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Zusammenfassung: | Solid dispersion has shown to be a promising formulation strategy to enhance dissolution for hydrophobic drugs. However, solid dispersions are often thermodynamically unstable, there is a continuous interest in studying their stabilities. In this study, attenuated total reflectance Fourier transform infrared (ATR-FTIR) was used to compare the amount of crystalline nifedipine formed in different formula of poly(ethylene glycol) (PEG)–nifedipine solid dispersions when exposed at various relative humidities (RHs) for 2h at 40°C. The ratio of the crystalline nifedipine band and an internal reference band in the out of plane δ(C─H) region has been used to indicate the relative degree of drug crystallisation in a sample. A band ratio of ∼0.05 and 0.5 was respectively indicative of a fully amorphous or crystallised drug in the formula. Results show that increasing the RH generally increases the amount of crystalline nifedipine. Formulations with low (5%, w/w) nifedipine concentration in higher molecular weight PEG were found to be better at resisting crystallisation. Deliquescence of the 10% nifedipine in PEG 4000 was observed at 77% and 100% RH with a reduction in crystalline nifedipine. All 5% (w/w) nifedipine samples were stable at RH below 77%. Crystallisation of nifedipine occurred at all RH when drug loading was increased to 10% (w/w). |
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ISSN: | 0022-3549 1520-6017 |
DOI: | 10.1002/jps.24261 |