title: Evaluation of modified gum karaya as carrier for the dissolution enhancement of poorly water-soluble drug nimodipine.
abstract: Modified gum karaya (MGK), a recently developed excipient was evaluated as carrier for dissolution enhancement of poorly soluble drug, nimodipine (NM). The advantages of MGK over the parent gum karaya (GK) were illustrated by differences in the in vitro dissolution profiles of respective solid mixtures prepared by co-grinding technique. The influence of process variable, such as polysaccharide concentration and method of preparation of solid mixture on dissolution rate was studied. Solubility studies were also performed to explain the differences in dissolution rate. Solid mixtures were characterized by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and scanning electron microscopy (SEM). The dissolution rate of NM was increased as the MGK concentration increased and optimum ratio was found to be 1:9 w/w ratio (NM:MGK). It is found that method of preparation of solid mixtures was significantly effected the dissolution rate of NM from solid mixtures. The order of method of preparation in according to their Dissolution Efficiency is physical mixture < co-grinding mixture < swollen carrier mixture < kneading mixture (water as kneading agent) < kneading mixture (70% v/v ethanol as kneading agent) < solid dispersion. Though, the solid mixtures prepared by other methods like solid dispersion, swollen carrier mixture and kneading technique gave faster release, co-grinding mixture prepared in 1:9 w/w ratio (NM:MGK) was found to exhibit a significant improvement in dissolution rate without requiring addition of organic solvents or high temperatures for its preparation and the process is less cumbersome. Hence, co-grinding technique appears to be more easier and the most convenient method from a practical point of view.
authors.affiliation: Division of Industrial Pharmacy, Department of Pharmaceutical Sciences, Andhra University, Visakhapatnam 530003, India. mmbgedela@hotmail.com
authors.forename: G V
authors.initials: GV
authors.lastname: Murali Mohan Babu
authors.forename: Ch D S
authors.initials: ChD
authors.lastname: Prasad
authors.forename: K V
authors.initials: KV
authors.lastname: Ramana Murthy
mesh_terms: D000143:Acids / Q000032:analysis; D000327:Adsorption; D000465:Algorithms; D002121:Calcium Channel Blockers / Q000008:administration & dosage* / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D004337:Drug Carriers; D004339:Drug Compounding; D007618:Karaya Gum; D008855:Microscopy, Electron, Scanning; D009553:Nimodipine / Q000008:administration & dosage* / Q000737:chemistry; D012995:Solubility; D014783:Viscosity; D014961:X-Ray Diffraction
chemical_list: D000143:Acids; D002121:Calcium Channel Blockers; D004337:Drug Carriers; D009553:Nimodipine; D007618:Karaya Gum