[Kinetic pattern of folic acid release from polyurethane matrices of varied structures].

The development of new bioactive polymeric materials is very topical. The goal of the present work was to use an optimized reversed-phase HPLC method to determine the release of folic acid (FA) from polyurethane carriers of different structures in vitro. Two types of polymeric samples were studied as FA carriers: linear (covalent bonds between FA and the carrier; 13 mass % and 26 mass % FA--samples 1 and 2) and cross-linked (hydrogen bonds between FA and the carrier; 1 mass % FA and 6 mass % FA--samples 3 and 4). The rate and pattern of the FA release was shown to depend on the way of FA immobilization on the polymeric carrier and the polymer structure. The cumulative amount of FA released from the linear samples (1 and 2) into model medium on the 28th day was 1.20 mg/ml and 2.17 mg/ml, respectively. The cumulative amount of FA released from the cross-linked samples (3 and 4) on the 28th day was 0.16 mg/ml and 0.38 mg/ml, respectively.