Design and optimization of colon-targeted system of theophylline for chronotherapy of nocturnal asthma

✍ Scribed by Mayur M. Patel; Avani F. Amin

• Book ID: 102912893
• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 520 KB
• Volume: 100
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.22406

✦ Synopsis

The objective of the present work was to develop a delayed-onset controlledrelease 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 R S100:ethyl cellulose (EC) coating capable of delaying the drug release. The system was optimized using a 3 2 full factorial design, wherein two factors [ratio of Eudragit R S100:EC and the coating level (% w/w)] were evaluated for lag time, t 50 and t 80 . The optimum formulation consisted of Eudragit R 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 5 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 5 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.