Drug-incorporated silicone discs as sustained release capsules. I. Chloroqine diphosphate
✍ Scribed by Fu, J. C. ;Kale, A. K. ;Moyer, D. L.
- Publisher
- John Wiley and Sons
- Year
- 1973
- Tongue
- English
- Weight
- 367 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0021-9304
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✦ Synopsis
Abstract
Quantitative investigation of the rate of diffusion (in vitro) of chloroquine diphosphate, an antimalarial drug, from silicone rubber (Silastic) discs is reported here. The viscosity of the polymer is reduced to facilitate the formation of a more homogeneous drug‐polymer mixture from which the discs are made. The average quantity of drug released daily from these vulcanized silicone rubber discs is measured as a function of the amount of drug initially incorporated in the polymeric mass. Discs with 9 and 36 mg of chloroquine diphosphate incorporated continue to release drug in microgram quantities for a period of over four months. The presence of low viscosity silicone fluid (20 centistokes) in the discs was found to cause no significant alteration in the drug release rate. The effect of agitation of the fluid in which the discs are immersed is also investigated. Results from samples prepared from different batches of polymer showed comparable results, indicating the rather homogeneous nature of the polymer‐drug system. All samples showed high release rates during the first few days followed by much lower and more or less constant drug release on subsequent days over a period of months.
Concentrations of the drug in the eluant is determined spectrophotometrically by utilizing the 220‐ and 343‐mμ peaks of chloroquine diphosphate as well as spectrofluorometrically by measuring the percent fluorescence at 405 mμ (360‐mμ excitation).