Formulation and evaluation of pulsatile drug delivery system
Rajesh N, Vidya JS, Manjunath MS, Bhavya KN
The present work deals with design and evaluation of oral site-specific, pulsatile drug delivery chonopharmaceutical ‘Tablet in Capsule’ system containing Salbutamol Sulphate (SBS), as model drug. It can be targeted to colon in a pH and time dependent manner, to modulate the drug level in synchony with the circadian rhythm of nocturnal asthma. The core tablets of SBS were formulated using wet granulation method with a superdisintegrant. Eudragit S100 and Eudragit L100 were used as pH dependent polymers for coating the core tablet which was filled in to the capsule. The ratio of Eudragit S100 and Eudragit L100 on In-vitro drug release and the coating level was optimized using 32 full factorial designs. Dissolution studies of ‘Tablet-in-Capsule’ device in media with different pH have been carried out. The lag time prior to drug release was highly affected by the coating level. The level of coating and the ratio of polymer has significant role on drug release behaviours. The gamma scintigraphic study pointed out the capability of the system to release the drug in lower parts of gastro intestinal tract after a programmed lag time for nocturnal asthma.