Comparison of the rate of release of active substances from solutions of hydroxymethylpropyl cellulose and hydroxyethyl cellulose for selecting the optimal polymer for the development of ear drops

Drops are a liquid dosage form, which can go out of target place, so the use of a substance that gives the drops viscosity which prevents solution of drops to go out of place of applications, as polymers which are very important but that use may effect on release of active ingredients in drops, so in this study we studied the effect of used HPMC which is polymer used for viscoelastic, as well as an excipient and controlled-delivery component in ear drops. The aim of the work was to compare the rate of release of active substances from solutions of hydroxymethylpropyl cellulose and hy-droxyethyl cellulose, as the choice of the optimal polymer for the development of ear drops. We have studied the use of HPMC and HEC polymer for obtaining viscoelastic liquid dosage forms in the form of ear drops, as excipients that control the release. For the analysis, ofloxacin was chosen as active substances, in view of its high activity on microorganisms that cause otitis media, and HPMC and HEC, ethyl alcohol 96% and purified water were used as auxiliary substances in the analyzed compositions. To determine the viscosity of solutions, we have chosen a glass capillary viscometer VPZH-2, in accordance with the recommendation of the State Pharmaceutical Organization. The release was carried out by equilibrium dialysis through a semiper-meable membrane using a regenerated cellulose tubular membrane (model T3). The HPLC method was used to identify the active substance. In view of the data obtained on the release of the active substance, for the development of the composition and technology of ear drops, as an auxiliary component, we chose HPMC.