Photostability nifedipine in powder, obtained by crushing tablet, granule or fine-granule.
- 1 January 1990
- journal article
- Published by Japanese Society of Pharmaceutical Health Care and Sciences in Japanese Journal of Hospital Pharmacy
- Vol. 16 (3) , 189-197
- https://doi.org/10.5649/jjphcs1975.16.189
Abstract
The photostability of nifedipine (NP) was studied in heterogeneous solid-state preparations. Two kinds of powders, obtained by crushing tablets, granule and fine-granule which were commerced on Japanese market, were subjected to the test, and their photostabilities of NP were compared with that of NP in standard sample (control).The protective effect of packaging with colored glassine-paper on photodegradation of NP was also examined.The preparation samples were exposed to normal room light, fluorescent lamp and day light, under the conditions of 750 lux of average irradiation and 35% of relative humidity at ambient for 720 hours. Changes of amount of NP, its nitroso-derivative and nitro-derivative were determined with highperformance liquid chromatography (HPLC).NP in each preparation which was packaged with white glassine-paper decomposed rapidly after exposure to light, according to pseudo first-order kinetics.The result of regression analysis suggested that NP of two kinds of powders, granule and fine-granule decomposed completely in about 120 hours.However, the amount of NP in control was maintained above 65% of the original potency for 120 hours after exposure to light when it was packaged with red glassinepaper. From the relationship between photodegradation rate constants and area under the transmission curves of various colored glassine-papers, the range of wavelength between 300nm and 460nm may relate to the decomposition of NP.Furthermore, two unknown peaks which increased after exposure to light were observed on HPLC chromatogram of NP.Keywords
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