title: Rheological, mucoadhesive and release properties of pluronic F-127 gel and pluronic F-127/polycarbophil mixed gel systems.
abstract: This study was designed to combine the mucoadhesive property of Noveon and the thermosensitive property of Pluronic F-127 into one gel system. A rheological study of Pluronic aqueous sols (10-35%), Noveon gels (0.5-2%) and of mixed gels containing Pluronic (10-17.5%) and polycarbophil (0.5-2.5%) was conducted at different temperatures (15-35 degrees C). The viscosity of Pluronic sols increased with an increase in temperature and the mixed gels had thermoreversible property. The viscosity of mixed gels was higher than that of the Pluronic sols containing only Pluronic because of the increase in total polymer concentration. No interaction was found between -COOH groups of Noveon and Pluronic molecules at the studied concentrations of polymers; the viscosity of mixed gels containing un-neutralized Noveon was lower than that of the neutralized mixed gels. The effect of Pluronic F-127 on the mucoadhesive property of Noveon was investigated. The mucoadhesive properties of Pluronic and Noveon gels were compared by a force of detachment test. It was found that Pluronic and Noveon gels showed approximately the same mucoadhesive strength. However, there were significant differences in the viscosity of Noveon and Pluronic gels. The adhesive force of the mixed gel was almost same as that of the Noveon gel. The Pluronic did not affect the adhesive power of Noveon and the increased viscosity did not affect the bioadhesive force of the mixed gels. In spite of increasing viscosity of the gel, the percentage of released model material (mannitol) increased with increasing temperature. This is based on the previously reported observation that the interaction between the Pluronic molecules squeezed mannitol molecules out of the polymer chains. The mannitol release obeyed zero-order kinetics and the flux values of mixed gels at 15 and 35 degrees C were very similar. The Noveon chains among Pluronic chains probably hindered the diffusion of mannitol molecules and the release was thus controlled by Noveon. The combination of a thermosensitive polymer like Pluronic and a bioadhesive polymer like Noveon appears promising from a pharmaceutical viewpoint. These gel systems may find use in the development of bioadhesive, thermosensitive and controlled release formulations.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Wisconsin University, Madison, WI, USA. feegosh@yahoo.com
authors.forename: F
authors.initials: F
authors.lastname: Tirnaksiz
authors.forename: J R
authors.initials: JR
authors.lastname: Robinson
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000268:Adhesiveness; D000818:Animals; D005753:Gastric Mucosa / Q000378:metabolism; D005782:Gels; D066298:In Vitro Techniques; D008353:Mannitol / Q000378:metabolism; D009092:Mucous Membrane / Q000737:chemistry; D020442:Poloxamer / Q000737:chemistry*; D011817:Rabbits; D012212:Rheology; D013696:Temperature; D014783:Viscosity
chemical_list: D000180:Acrylic Resins; D005782:Gels; D020442:Poloxamer; D008353:Mannitol; C030312:calcium polycarbophil