OPTIMIZATION OF GASTRO RETENTIVE DRUG DELIVERY SYSTEM OF LABETALOL HYDROCHLORIDE USING SIMPLEX CENTROID DESIGN

Labetalol Hydrochloride due to its pH dependant solubility in range of 6-10 shows 10-80% variability in bioavailability, used in treatment of hypertension. Due to its short half life i.e. 3-6 hrs, it is administered twice a daily. Therefore to improve bioavailability and patient compliance in this study attempt has been made to develop an oral floating tablet of Labetalol hydrochloride. An optimized floating drug delivery system (GFDDS) of Labetalol Hydrochloride was developed using simplex Centroid design. In this design Hydroxypropyl methyl cellulose K4M (X1), Carbopol 934P (X2), Sodium carboxymethylcellulose (X3) were used as independent variables and floating lag time,t₅₀% and t₈₀%  as responses. In this design effervescent matrix tablets were prepared by combination of citric acid and sodium bicarbonate. Results of ANOVA indicated, low levels of X2 and X3, and high level of X1 should be used to manufacture the tablet formulations with desired in vitro floating time, t₅₀% and t₈₀%. Kinetics of drug release from tablet followed Korsmeyer–Peppas model by anomalous non-Fickian diffusion. It was concluded that gastro retentive tablet of Labetalol hydrochloride can be prepared via floating mechanism to increase residence time of drug in stomach and there by increasing its absorption. The present study demonstrates that use of simplex Centroid design in development of floating tablets with minimum experimentation