Influence of Acrylic Resins and Ethylcellulose on Sustainment of Indometacin via Solid Dispersions
Yassein El-said Hamza, Soad Yehia Amin, and Ahmed H. El-Shafey
Pharmaceutics Department, Faculty of Pharmacy, Cairo University, Cairo (Egypt)
Solid dispersions of indometacin in different release-retarding materials were prepared using acrylic resins (EudragitÃ¢ RSPM, RLPM, E30D) and ethylcellulose 100 in different ratios, adopting the co-precipitation method, then compressed into tablets. Physical parameters and release rates were evaluated. The effects of various release retardants on anti-inflammatory characteristics and ulcerogenicity of indometacin were studied with the most appropriate preparation reached. Kollidon K-25 and hydroxypropylmethylcellulose (HPMC) were used as channeling agents to improve drug release. It was found that increasing contents of Eudragit RSPM were associated with a concomitant decrease of the drug release rate. The co-precipitate prepared with 20 % w/w Eudragit RSPM showed the highest retardation in the release profile and, hence, the incorporation of 10 % Kollidon K-25 modified the release profile. On the other hand, the release rate profile of indometacin from tabletted Eudragit RLPM co-precipitates showed a progressive decrease accompanying the increase of the Eudragit RLPM proportion in the co-precipitate. It was concluded that 1 and 2 % of Eudragit E30D retarded the drug release excess-ively over 8 h. However, a co-precipitate prepared with 0.5 % Eudragit E30D showed a remarkable drug release profile. Ethylcellulose 100 in ratios of 5, 10 and 20 % showed various extents of prolongation in drug release from tabletted co-precipitates. Incorporation of either 10 % Kollidon K-25 or 10 % hydroxy-propylmethylcellulose with the co-precipitate prepared with 20 % ethylcellulose 100 showed a marked improvement of the release rate. Tablets containing the co-precipitate of indometacin and 20 % Eudragit RSPM with 10 % Kollidon K-25 showed maximum anti-inflammatory activity with the least ulcer index compared to commercial indometacin capsules.
Key words Acrylic resins Â· Ethylcellulose Â· EudragitÃ¢ Â· Hydroxypropylmethylcellulose Â· Indometacin Â· Kollidon K-25 Â· Solid dispersions Â· Sustained release tablets
pharmind 2000, Nr. 7, Seite 551