title: Calcium silicate based microspheres of repaglinide for gastroretentive floating drug delivery: preparation and in vitro characterization.
abstract: Gastroretentive dosage forms have potential for use as controlled-release drug delivery systems. Multiple unit systems avoid the 'all-or-none' gastric emptying nature of single-unit systems. A controlled release system designed to increase its residence time in the stomach without contact with the mucosa was achieved through the preparation of floating microspheres by the emulsion solvent diffusion technique consisting of (i) calcium silicate (FLR) as porous carrier; (ii) repaglinide, an oral hypoglycemic agent; and (iii) Eudragit S as polymer. The effect of various formulation and process variables on the internal and external particle morphology, micromeritic properties, in vitro floating behavior, physical state of the incorporated drug, drug loading and in vitro drug release were studied. The microparticles were found to be regular in shape and highly porous. The release rate was determined in simulated gastro-intestinal fluids at 37 degrees C. The formulation demonstrated favorable in vitro floating and release characteristics. The drug encapsulation efficiency was high. Incorporation of FLR in the microspheres proved to be an effective method to achieve the desired release behavior and buoyancy. The designed system, combining excellent buoyant ability and suitable drug release pattern, could possibly be advantageous in terms of increased bioavailability of repaglinide.
authors.affiliation: Department of Pharmaceutical Sciences, Dr. H. S. Gour University, Sagar-470 003, India.
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Jain
authors.forename: A M
authors.initials: AM
authors.lastname: Awasthi
authors.forename: N K
authors.initials: NK
authors.lastname: Jain
authors.forename: G P
authors.initials: GP
authors.lastname: Agrawal
mesh_terms: D000465:Algorithms; D001682:Biological Availability; D017610:Calcium Compounds / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002219:Carbamates / Q000008:administration & dosage* / Q000737:chemistry; D004337:Drug Carriers; D016503:Drug Delivery Systems; D006207:Half-Life; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D010880:Piperidines / Q000008:administration & dosage* / Q000737:chemistry; D017640:Silicates / Q000737:chemistry*; D012995:Solubility; D013696:Temperature
chemical_list: D017610:Calcium Compounds; D002219:Carbamates; D004337:Drug Carriers; D007004:Hypoglycemic Agents; D010880:Piperidines; D017640:Silicates; C072379:repaglinide; C031293:calcium silicate