title: Rheological evaluation of thermosensitive and mucoadhesive vaginal gels in physiological conditions.
abstract: The timely gelation and retention of in situ-gelling vaginal formulations would be fundamental to improve the efficacy of drugs. In this study, various rheological properties of clotrimazole gels were evaluated for predicting their performance in vagina. Two kinds of thermosensitive and mucoadhesive formulations were composed of poloxamer 407 (P407, 15%), polycarbophil (0.2%), and different amounts of P188 (15 vs. 20%). Both formulations were Newtonian at 20 degrees C but non-Newtonian at 37 degrees C. Although both liquid formulations gelled below the vaginal temperature, they differed in gelation time and viscoelastic properties in the presence of vaginal fluid simulant. At body temperature, the formulation with 20% of P188 gelled within 35 s but it took two times longer for the other one gelled. Upon dilution with simulated vaginal fluid, the formulation with 20% of P188 retained the rheology of a gel, but the other one lost the viscoelastic properties typical for a gel. Moreover, after dilution with simulated vaginal fluid, the elastic modulus was orders of magnitude higher in the formulations with 20% of P188 relative to the other one. These results indicate that the rheological evaluation at the physiologic conditions needs to be preceded to develop more effective in situ-gelling vaginal formulations.
authors.affiliation: National Research Laboratory for Drug and Gene Delivery, College of Pharmacy, Seoul National University, San 56-1, Shinlim-Dong, Kwanak-Ku, 151-742, Seoul, South Korea.
authors.forename: Jung Yun
authors.initials: JY
authors.lastname: Chang
authors.forename: Yu Kyoung
authors.initials: YK
authors.lastname: Oh
authors.forename: Han-gon
authors.initials: HG
authors.lastname: Choi
authors.forename: Yang Bae
authors.initials: YB
authors.lastname: Kim
authors.forename: Chong-Kook
authors.initials: CK
authors.lastname: Kim
mesh_terms: D000180:Acrylic Resins; D000818:Animals; D001826:Body Fluids / Q000502:physiology; D004337:Drug Carriers; D004548:Elasticity; D005260:Female; D005782:Gels; D020442:Poloxamer; D012212:Rheology; D013696:Temperature; D014014:Tissue Adhesives; D014621:Vagina / Q000502:physiology; D014622:Vaginal Creams, Foams, and Jellies; D014783:Viscosity
chemical_list: D000180:Acrylic Resins; D004337:Drug Carriers; D005782:Gels; D014014:Tissue Adhesives; D014622:Vaginal Creams, Foams, and Jellies; D020442:Poloxamer; C030312:calcium polycarbophil