Development of time and pH dependent controlled release colon specific delivery of tinidazole

ABSTRACT

Tinidazole is used in treatment of amoebiasis and other protozoal infections in doses of 2.0 g/ day [60 mg/kg] for three days. In the present paper, controlled release formulation of tinidazole was developed with an objective to achieve colon specific drug delivery with reduced frequency of dosing, to minimize gastric side effects and thus to increase patient compliance. Matrix systems of tinidazole [500 mg] were prepared by using swellable and pH dependent polymers like hydroxypropyl methylcellulose [HPMC K4M and K15M] and eudragit [eudragit L-100 and S-100]. Prepared tablets were enteric coated in order to overcome variability in gastric emptying time and delay in the release, to reduce gastric side effects and to provide prolonged localized action in colon. Process of manufacture was optimized during the scale up studies. Bioavailability study [using parallel group design] was carried of on conventional marketed, developed uncoated and enteric coated tablets in healthy human volunteers. Bioavailability study showed that greater portion of tinidazole was released in the large intestine and drug level in plasma was above 4 micro g/mL in blood for 24 hours. From the results of this study it appears that, the proposed single enteric coated tinidazole [500 mg] tablet per day could be used in place of 3-4 doses of 500 mg tinidazole conventional tablet with better control of drug release for targeted drug delivery. In addition developed colon-specific drug delivery system [CDDS] was relatively inexpensive and easy to manufacture using conventional pharmaceutical coating technique