FORMULATION AND EVALUATION OF VERAPAMIL LOADED HOLLOW MICROSPHERESAbstract
Verapamil Hydrochloride is phenyl alkyl amine derivative, Calcium channel blocker: Class IV, antiarrhythmic drug having short half-life of 2.8 – 7.4 hours so requires frequent dosing of 40 -120 mg thrice for treatment of arrhythmia and 80 -120mg thrice a day for treatment of angina and hypertension. It degrades at neutral and alkaline pH. So, study was taken up to Formulate, Optimize and Evaluate the Hollow microspheres of Verapamil Hydrochloride to prevent degradation and to reduce frequency of dose by having sustained release effect. Hollow microsphere or micro-balloons were prepared by non – aqueous solvent evaporation method using Ethyl cellulose and Eudragit RS 100 and optimized by changing drug: polymer ratio, and polymer combination. Thirteen batches containing only Ethyl Cellulose, only Eudragit RS 100 and both Ethyl Cellulose and Eudragit RS 100 were prepared and evaluated. Drug to Polymer ratio of 1:2 was found to be optimized. Micro-balloons were stable, white colored, spherical, free flowing in nature and showed controlled release up to 12 hours. The drug release from the micro-balloons followed Higuchi model indicating diffusion controlled non-Fickian drug release. Optimized formulation batch showed percentage yield 82.99%, percentage buoyancy 86.05 ± 0.93%, particle size 305.17 ± 3.43µm and percentage drug entrapment efficiency 83.45 ± 0.21%.