title: Effect of rheological parameters on pharmaceutical availability of ketoprofen from hydrogel products made on Carbopol base.
abstract: Rheological parameters were tested in market hydrogel products of anti-inflammatory activity. Their prescription was worked out on Carbopol base. The rate of volatile components loss from pharmaceutical preparations was estimated with gravimetric method, while their viscosity parameters (structural viscosity, yield stress, the area of hysteresis loop) were determined with cone-plate digital rheometer. The kinetics of the therapeutic agent (ketoprofen) release through a standard Viscing membrane to external compartment was tested in hydrogels in vitro. The aim of the study was to determine the relationship between rheological parameters dependent on the prescription of the tested hydrogels and pharmaceutical availability of ketoprofen. Pharmaceutical preparations of anti-inflammatory activity made on Carbopol base are non-Newtonian liquids diluted with shear. Due to ethanol content in their prescription, after application on skin, the increase of structural viscosity and the decrease of ketoprofen pharmaceutical availability accompany the process of volatile components loss from the surface layer of the preparation. Ketoprom hydrogel, having propylene glycol in its composition, is characterized by higher values of viscosity, hysteresis pool area and yield stress than Fastum preparation. Insignificant differences between experimentally determined in vitro areas under the curves of ketoprofen release are associated with rheological parameters of the investigated hydrogels, which was anticipated on the basis of Einstein-Smoluchowski's equation. Ketoprofen penetration from the tested pharmaceutical products on Carbopol base to the external compartment is in accordance with kinetics of "0" order and is diffusion-controlled.
authors.affiliation: Department of Drug Form Technology, Applied Pharmacy Faculty Medical University of Lodz. mmzgoda@pharm.am.lodz.pl
authors.forename: Marian Mikołaj
authors.initials: MM
authors.lastname: Zgoda
authors.forename: Justyna
authors.initials: J
authors.lastname: Kołodziejska
mesh_terms: D000180:Acrylic Resins; D019540:Area Under Curve; D001682:Biological Availability; D003692:Delayed-Action Preparations; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D020100:Hydrogels / Q000737:chemistry*; D007660:Ketoprofen / Q000493:pharmacokinetics*; D011145:Polyvinyls / Q000737:chemistry; D012212:Rheology; D014783:Viscosity
chemical_list: D000180:Acrylic Resins; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D020100:Hydrogels; D011145:Polyvinyls; C006912:carboxypolymethylene; D007660:Ketoprofen