| abstract |
Polycarbophil or crosslinked acrylic acid polymer is prepared in a solvent selected from acetone, alkyl acetates, and mixtures thereof, in the presence of an effective amount of divinyl glycol crosslinker, and in the presence of an effective amount of a suitable initiator allowing for polymerization to proceed at a temperature below 100°C at atmospheric pressure. The polymer produced has average particle size of less than 10 microns without grinding, its viscosity is greater than about 50,000 cps when measured in water at 1% concentration, and it adheres to mucous membranes. By preparing the polymer in a non-aqueous solvent, the need for aqueous washing is avoided and the subsequent and enormous swelling of the polymer is avoided which means that prolonged and excessive drying inherent in the known processes is avoided. |