Chem. Pharm. Bull. 55(8) 1141—1147 (2007)

characterized by recurrent course for many years, is primarily based on metronidazole preparations. This is the first compound authorized by FDA for local acne rosacea therapy. Majority of patients respond to oral administration of an antibiotic complemented with topical application of metronidazole. The available metronidazole products involve 0.75—2% ointments and gels. To achieve good compliance, metronidazole products need to be characterized by prolonged release of the compound, which can be achieved, for instance, by binding the drug in a polymer bed, although, the amount of drug released should enable bactericidal activity of metronidazole. Numerous reports have been devoted to the study of interaction between polyacrylic acid and various drugs or polymers, such as polyvinylpyrrolidine or carboxymethylcellulose. The polyacrylates possess an interesting property of water binding in the form of so-called primary bound water, secondary bound water, and bulk water. The use of polyacrylates or their compositions with methylcellulose as metronidazole carriers in the dermal preparations may provide interesting patterns of release at the site of application. The aim of this study was to evaluate the effect of various acrylic acid polymers, in composition with methylcellulose on metronidazole release rate from hydrogels proposed for the treatment of acne rosacea.