Polyacrylic acid/polyvinylpyrrolidone bipolymeric systems. I. Rheological and mucoadhesive properties of formulations potentially useful for the treatment of dry-eye-syndrome.

For the treatment of dry-eye-syndrome preparations containing polymers as active agents are used. Polyacrylic acid (PAA) is a well known mucoadhesive polymer. For ocular use, however, the very high viscous gel systems can cause irritation post application which can result in a low patient compliance. In this study we have shown that it is possible to formulate PAA based low viscous formulations with polyvinylpyrrolidone (PVP) as 2nd polymer. The survey of the systems for the parameters microviscosity with polarization and oscillatory rheology shows that the 2nd polymer influences the structure of the PAA gel framework that causes the significant decrease in apparent viscosity of the combination. The mucoadhesion and rheological characteristics were determined by means of rheological methods. The acquired results, low viscosity and a high mucoadhesion index in comparison with the monopolymer PAA preparation and with two PAA containing commercial artificial tear preparations, Vidisic and Thilo Tears, led to the conclusion that the combination of the two polymers, PAA and PVP, could be advantageous for the treatment of the dry eye.