Formulation and Evaluation of Multilayer Floating Tablet

Abstract

Multi-layer floating tablet of ciprofloxacin ware designed based on gas formation technique. The core tablet contain ciprofloxacin hydrochloride coated with hydroxypropyl methyl cellulose (protective coat), with sodium bicarbonate and citric (effervescent layer), and Eudragit^@ RL 30D (gas entrapped membrane), respectively. Eudragit^@ RL 30D is a good candidate for the gas entrapped membrane because it have high flexibility, high puncture strength and high (two time than Eudragit^@ RS 30D) water permeability. When the system placed in dissolution medium (0.1N HCl) the gas entrapment membrane allow the acidic water to come inside the membrane  react with sodium bicarbonate and generate the co₂ this co₂ entrapped into the outer polymeric gas entrapment  membrane and decrease the density of  the tablet less than 1gm/ml and the tablet become float. The formulation variables which affect the floating properties and drug release are investigated.  The tablets which are prepared by direct compression have the shorter lag time as compare to tablet by wet granulation. Higher amount of HPMC also delay the drug release from the tablet. Excessive amount of gas forming agent did not affect the lag time but increase the rate of drug release and increase weight of the tablet and also increase the coating level of gas entrapment layer. The plasticizer also play an important role here as the amount of plasticizer increase the lag time also increase but using the plasticizer more than 25% w/w the gas entrapment coat goes to break when placed in dissolution medium. Decrease the amount of plasticizer also decrease the lag time (shorter lag time) but decreasing the amount of plasticizer less than 13% w/w the tablet unable to float and the gas entrapment coat goes to break. Finally a good floating and sustain release tablet seems to be a promising gastro retentive drug delivery system.