title: Role of various natural, synthetic and semi-synthetic polymers on drug release kinetics of losartan potassium oral controlled release tablets.
abstract: OBJECTIVE
  The objective of the present work was to formulate and to characterize controlled release matrix tablets of losartan potassium in order to improve bioavailability and to minimize the frequency of administration and increase the patient compliance.
  
  
  METHODS
  Losartan potassium controlled release matrix tablets were prepared by direct compression technique by the use of different natural, synthetic and semisynthetic polymers such as gum copal, gum acacia, hydroxypropyl methyl cellulose K100 (HPMC K100), eudragit RL 100 and carboxy methyl ethyl cellulose (CMEC) individually and also in combination. Studies were carried out to study the influence of type of polymer on drug release rate. All the formulations were subjected to physiochemical characterization such as weight variation, hardness, thickness, friability, drug content, and swelling index. In vitro dissolution studies were carried out simulated gastric fluid (pH 1.2) for first 2 h and followed by simulated intestinal fluid (pH 6.8) up to 24 h, and obtained dissolution data were fitted to in vitro release kinetic equations in order to know the order of kinetics and mechanism of drug release.
  
  
  CONCLUSIONS
  Results of physiochemical characterization of losartan potassium matrix tablets were within acceptable limits. Formulation containing HPMC K100 and CMEC achieved the desired drug release profile up to 24 h followed zero order kinetics, release pattern dominated by Korsmeyer - Peppas model and mechanism of drug release by nonfickian diffusion. The good correlation obtained from Hixson-Crowell model indicates that changes in surface area of the tablet also influences the drug release.
  
  
  CONCLUSIONS
  Based on the results, losartan potassium controlled release matrix tablets prepared by employing HPMC K100 and CMEC can attain the desired drug release up to 24 h, which results in maintaining steady state concentration and improving bioavailability.
authors.affiliation: Department of Pharmaceutics, Jayamukhi College of Pharmacy, Warangal, Andhra Pradesh, India.
authors.forename: J
authors.initials: J
authors.lastname: Jayasree
authors.affiliation: Department of Pharmaceutics, Jayamukhi College of Pharmacy, Warangal, Andhra Pradesh, India ; Department of Pharmaceutics, Sree Vidyanikethan College of Pharmacy, Tirupati, Andhra Pradesh, India.
authors.forename: S
authors.initials: S
authors.lastname: Sivaneswari
authors.affiliation: Department of Pharmaceutics, Jayamukhi College of Pharmacy, Warangal, Andhra Pradesh, India.
authors.forename: G
authors.initials: G
authors.lastname: Hemalatha
authors.affiliation: Department of Pharmaceutics, Jayamukhi College of Pharmacy, Warangal, Andhra Pradesh, India.
authors.forename: N
authors.initials: N
authors.lastname: Preethi
authors.affiliation: Department of Pharmaceutics, Jayamukhi College of Pharmacy, Warangal, Andhra Pradesh, India.
authors.forename: B
authors.initials: B
authors.lastname: Mounika
authors.affiliation: Department of Pharmaceutics, Jayamukhi College of Pharmacy, Warangal, Andhra Pradesh, India.
authors.forename: S Vasudeva
authors.initials: SV
authors.lastname: Murthy
keywords: Carboxy methyl ethyl cellulose; eudragit RL 100; gum acacia; gum copal; hydroxypropyl methyl cellulose K100; losartan potassium