Formulation and Evaluation of Cinnarizine Extended Release Tablets

A. Surekha*, CH. Praveen kumar, K. Gnana Prakash
Department of Pharmaceutics, Ratnam Institute of Pharmacy, Pidathapolur, SPSR Nellore-524346, Andhra Pradesh, India.

A B S T R A C T
Cinnarizine is an anti histaminic, derivative of piperazine and has high affinity to H1 receptors, extensively used for the treatment of motionsickness, vertigo / menieres disease, nausea and vomiting. Cinnarazine as an immediate release dosage form causes GI irritation and has less halflife (2- 4 hrs). So the present study was to formulate an extended drug delivery system of cinnarizine. The tablets were prepared by direct compression technique using different hydrophobic and hydrophilic polymers like ethyl cellulose (EC), hydroxy propyl methyl cellulose (HPMC) in different ratios. The formulated tablets were evaluated for hardness, thickness, weight variation, content uniformity, in-vitro drug release and stability. Seven formulations with different proportion of aforementioned polymers were prepared to access their efficacy. The formulation containing 20% ethyl cellulose (CNZ-1) of cinnarizine has achieved 98% drug release for 12 Hrs. The drug release has been retarded with increase in the concentrations of hydrophobic polymer (Ethyl cellulose), and with increase in concentration of hydrophilic polymer (HPMC) the drug released within 7 hrs (CNZ-7). CNZ-1 shows more retarding effect and thus found that T₅₀ % value increases as concentration of EC increases. Korsemeyer-Peppas release exponent (n) values of all cinnarizine extended release tablets are greater than 1 indicating drug diffusion is rapid due to swelling in the polymer (case 2 transport). 
Keywords: Cinnarizine, HPMC, Drug release kinetics, Ethyl cellulose, Diffusion exponent (n)