title: Design, development and evaluation of clopidogrel bisulfate floating tablets.
abstract: OBJECTIVE
  The objective of the present work was to formulate and to characterize a floating drug delivery system for clopidogrel bisulphate to improve bioavailability and to minimize the side effects of the drug such as gastric bleeding and drug resistance development.
  
  
  METHODS
  Clopidogrel floating tablets were prepared by direct compression technique by the use of three polymers xanthan gum, hydroxypropyl methylcellulose (HPMC) K15M and HPMC K4M in different concentrations (20%, 25% and 30% w/w). Sodium bicarbonate (15% w/w) and microcrystalline cellulose (30% w/w) were used as gas generating agent and diluent respectively. Studies were carried out on floating behavior and influence of type of polymer on drug release rate. All the formulations were subjected to various quality control and in-vitro dissolution studies in 0.1 N hydrochloric acid (1.2 pH) and corresponding dissolution data were fitted to popular release kinetic equations in order to evaluate release mechanisms and kinetics.
  
  
  CONCLUSIONS
  All the clopidogrel floating formulations followed first order kinetics, Higuchi drug release kinetics with diffusion as the dominant mechanism of drug release. As per Korsmeyer-Peppas equation, the release exponent "n" ranged 0.452-0.654 indicating that drug release from all the formulations was by non-Fickian diffusion mechanism. The drug release rate of clopidogrel was found to be affected by the type and concentration of the polymer used in the formulation (P < 0.05). As the concentration of the polymer was increased, the drug release was found to be retarded.
  
  
  CONCLUSIONS
  Based on the results, clopidogrel floating tablets prepared by employing xanthan gum at concentration 25% w/w (formulation F2) was the best formulation with desired in-vitro floating time and drug dissolution.
authors.affiliation: Department of Pharmaceutics, Bapatla College of Pharmacy, Bapatla, Andhra Pradesh, India.
authors.forename: K Rama Koteswara
authors.initials: KR
authors.lastname: Rao
authors.affiliation: Department of Pharmaceutics, Bapatla College of Pharmacy, Bapatla, Andhra Pradesh, India.
authors.forename: K Rajya
authors.initials: KR
authors.lastname: Lakshmi
keywords: Bioavailability; clopidogrel bisulfate; floating tablets; release kinetics; sustained release