title: Factors affecting the release of nifedipine from a swellable elementary osmotic pump.
abstract: Oral osmotic devices including an elementary osmotic pump (EOP) are efficient systems for the delivery of drugs with high/moderately water-solubility. In this study we designed a new type of EOP for the efficient delivery of poorly water-soluble and practically insoluble drugs. In this system, called swellable elementary osmotic pump (SEOP), drug is released from the delivery orifice in the form of a very fine dispersion of drug in gel which is ready for dissolution and absorption. Factors affecting the release of drug from the SEOP containing a poorly water-soluble drug, nifedipine, were explored extensively. To this end, effect of swelling and wetting agents, orifice size, concentration of osmotic agent, and hydrophobic plasticizer were investigated. Interestingly, in the absence or low concentration of a hydrophobic plasticizer (caster oil), the osmotic devices did not retain their integrity in dissolution media. Caster oil in concentration of > 1% was necessary for tablets to retain their integrity during dissolution process. A zero-order release kinetics for nifedipine was achieved following the effective optimization of the concentrations of swelling agent, osmotic agent, wetting agent, and also size of orifice and membrane thickness in SEOP. The zero-order release lasted for 10 hr at pH 6.8 dissolution medium. The designed SEOP is suggested as an efficient controlled delivery system for oral delivery of a poorly water soluble drug such as nifedipine.
authors.affiliation: School of Pharmacy at Medway, Universities of Kent and Greenwich, Kent, England. a.nokhodchi@kent.ac.uk
authors.forename: Ali
authors.initials: A
authors.lastname: Nokhodchi
authors.forename: Mohammed N
authors.initials: MN
authors.lastname: Momin
authors.forename: Javad
authors.initials: J
authors.lastname: Shokri
authors.forename: Mahbobeh
authors.initials: M
authors.lastname: Shahsavari
authors.forename: Parinaz Ahmad
authors.initials: PA
authors.lastname: Rashidi
mesh_terms: D000284:Administration, Oral; D002368:Castor Oil / Q000737:chemistry; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004339:Drug Compounding; D005782:Gels; D006863:Hydrogen-Ion Concentration; D065347:Hypromellose Derivatives; D007700:Kinetics; D008567:Membranes, Artificial; D008747:Methylcellulose / Q000031:analogs & derivatives / Q000737:chemistry; D008956:Models, Chemical; D009543:Nifedipine / Q000008:administration & dosage / Q000737:chemistry*; D009995:Osmosis; D010539:Permeability; D010968:Plasticizers / Q000737:chemistry; D011189:Potassium Chloride / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012995:Solubility; D013607:Tablets; D014867:Water / Q000737:chemistry; D014906:Wetting Agents / Q000737:chemistry
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005782:Gels; D008567:Membranes, Artificial; D010968:Plasticizers; D013607:Tablets; D014906:Wetting Agents; D014867:Water; D012967:Sodium Dodecyl Sulfate; C005062:acetylcellulose; D065347:Hypromellose Derivatives; D011189:Potassium Chloride; D002368:Castor Oil; D002482:Cellulose; D008747:Methylcellulose; D009543:Nifedipine