Effect of particle size of drug on conversion of crystals to an amorphous state in a solid dispersion with crospovidone.

Yuka Sugamura, Makiko Fujii, Sayaka Nakanishi, Ayako Suzuki, Yusuke Shibata, Naoya Koizumi, Yoshiteru Watanabe

Department of Pharmaceutics and Biopharmaceutics, Showa Pharmaceutical University, Machida, Tokyo, Japan.

Chemical & pharmaceutical bulletin 2011 Feb

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The effect of particle size on amorphization of drugs in a solid dispersion (SD) was investigated for two drugs, indomethacin (IM) and nifedipine (NP). The SD of drugs were prepared in a mixture with crospovidone by a variety of mechanical methods, and their properties investigated by particle sizing, thermal analysis, and powder X-ray diffraction. IM, which had an initial particle size of 1 µm and tends to aggregate, was forced through a sieve to break up the particles. NP, which had a large initial particle size, was jet-milled. In both cases, reduction of the particle size of the drugs enabled transition to an amorphous state below the melting point of the drug. The reduction in particle size is considered to enable increased contact between the crospovidone and drug particles, increasing interactions between the two compounds. © 2011 Pharmaceutical Society of Japan

Citation

Yuka Sugamura, Makiko Fujii, Sayaka Nakanishi, Ayako Suzuki, Yusuke Shibata, Naoya Koizumi, Yoshiteru Watanabe. Effect of particle size of drug on conversion of crystals to an amorphous state in a solid dispersion with crospovidone. Chemical & pharmaceutical bulletin. 2011 Feb;59(2):235-8