title: Optimization and physicochemical characterization of thermosensitive poloxamer gel containing puerarin for ophthalmic use.
abstract: The purpose of this study was to systematically optimize an ophthalmic thermosensitive poloxamer analogs gel containing puerarin that was a free flowing liquid below the room temperature and could shift to a gel with an eligible gel strength and bioadhesive force in physiological condition (dilution by the simulated tear fluid and at 35.0 degrees C). A two-factor, five-level central composite design (CCD) was employed to the optimization procedure. The effect of formulation variables (the w/v concentration of poloxamer 407 (X1) and poloxamer 188 (X2)) on a number of response variables (the gelation temperature before (Y1) and after (Y2) the simulated tear fluid diluted, the difference between them (Y3)) was systemically investigated. A second order polynomial equation was fitted to the data. The resulting equation and response surface plots were used to predict the responses in the optimal region. Finally, 21.0% (w/v) poloxamer 407 and 5.0% (w/v) poloxamer188 were chosen as the optimal poloxamer gel matrix. The influence of the other ingredients on the physicochemical properties of the formulation was also investigated. Hydroxypropyl-beta-cyclodextrin (HPCD) enhanced the gelation temperature and reduced the gel strength and the bioadhesive force, while puerarin and benzalkonium chloride (BC) had a comparatively smaller influence. All the isotonicity agents studied had the gelation temperatures lowered, and the gel strengths and the bioadhesive forces enhanced. But only sodium chloride appears to be a promising isotonicity agent for the poloxamer gel containing puerarin, HPCD and BC.
authors.affiliation: School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, P R China.
authors.forename: Hongyi
authors.initials: H
authors.lastname: Qi
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Chunyan
authors.initials: C
authors.lastname: Huang
authors.forename: Wenmin
authors.initials: W
authors.lastname: Li
authors.forename: Chunjie
authors.initials: C
authors.lastname: Wu
mesh_terms: D000073738:2-Hydroxypropyl-beta-cyclodextrin; D001548:Benzalkonium Compounds / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005782:Gels; D007529:Isoflavones / Q000737:chemistry*; D009883:Ophthalmic Solutions; D020442:Poloxamer / Q000737:chemistry*; D013696:Temperature; D047392:beta-Cyclodextrins / Q000737:chemistry
chemical_list: D001548:Benzalkonium Compounds; D005782:Gels; D007529:Isoflavones; D009883:Ophthalmic Solutions; D047392:beta-Cyclodextrins; D020442:Poloxamer; D000073738:2-Hydroxypropyl-beta-cyclodextrin; C033607:puerarin