Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2485608 | Journal of Pharmaceutical Sciences | 2011 | 13 Pages |
Abstract
The objective of the present work was to develop a delayed-onset controlled-release colon-targeted system of theophylline, and to achieve the chronotherapy of nocturnal asthma. The formulation consisted of a core tablet containing hydroxypropyl methylcellulose used for achieving controlled release of drug, and a Eudragit® S100:ethyl cellulose (EC) coating capable of delaying the drug release. The system was optimized using a 32 full factorial design, wherein two factors [ratio of Eudragit® S100:EC and the coating level (% w/w)] were evaluated for lag time, t50 and t80. The optimum formulation consisted of Eudragit® S100:EC in a 60:40 ratio and a coating level of 7.5% (w/w). Results showed that the tablets prepared according to the optimized values released no drug in the upper part of gastrointestinal tract; drug release was initiated at pH 6.4 (colon) after a lag time of 5Â h. In vivo evaluation (pharmacokinetic studies and roentgenography) in rabbits revealed that the tablet remained intact until it reaches the colon and the drug release was initiated after a lag time of 5Â h. Thus, it can be concluded that the developed system exhibited a promising colonic targeting and hence may be used for chronotherapy of nocturnal asthma.
Keywords
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Authors
Mayur M. Patel, Avani F. Amin,