Formulation development of theophylline in coated polymeric pellets for controlled oral drug delivery

This work is aimed at producing theophylline pellets for controlled oral drug delivery. Eight batches of theophylline pellets were prepared containing varying combinations (2.5 – 10% w/w) of sodium carboxymethyl cellulose, ethylcellulose and eudragit L-100 55. The flow properties of the pellets were determined and batches II and IV, which had the best flow were coated up to 30 – 60% using eudragit L-100. Sequential dissolution studies were carried out on the coated pellets in simulated gastric fluid (SGF), pH 1.2; simulated intestinal fluid (SIF), pH 6.8 and stimulated colonic fluid (SCF), pH 7.4. The dissolution data were subjected to kinetic treatment. The 30% coated pellets released uniform amounts of theophylline in the three media unlike the other batches. Though the coated pellets had the same super case-II transport mechanism of drug release, their release kinetics were different. The 30% coated batch-II pellets had the best controlled oral delivery of theophylline.