OPTIMIZATION OF POLYMER COATING LEVEL FOR COLON TARGETED SUSTAIN RELEASE METOPROLOL SUCCINATE PELLETS USING 32 FACTORIAL DESIGN

The present study is an attempt to minimize the dosing frequency and to target the Metoprolol succinate to the colon. Drug loaded pellets are coated with pH independent Eudragit RS100 and further coated with pH dependent Eudragit S100 in R and D pan coater. 3 ² full factorial design is applied to study the effect of extent of Eudragit S100 coating %w/w (X1) and extent of Eudragit RS100 coating %w/w (X2) as independent variables on the dependent variables (responses) are Y1=Q5 (% released after lag time of 5h) and Y2=Q90 (90% of drug release within 12h). The formulation were further characterized by in vitro dissolution study, drug release kinetics and micromeritic properties. 3² factorial design reveals that coating level of both the coats play a significant role in drug release property of which coating level of Eudragit RS 100 was more significant after the tablet reaches colon. Design expert software gives D5 as optimized batch having 20% w/w Eudragit RS 100 and 30% w/w with S100 as the drug release was below 20% in SIF so that it can be efficiently colon targeted, and the release is sustained up to 12 hr which is desirable for twice daily dosing of metoprolol.