Influence of various factors on the solubility of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine copolymers in water

The water solubility of N-vinylpyrrolidone and 2-methyl-5-vinylpyridine copolymers with various monomer ratios was investigated. Aqueous solutions of the copolymers had low critical mixing temperatures. The water solubility of the copolymers decreased with increasing pH and concentration of 2-methyl-2-vinylpyridine monomers. Correlation dependences for predicting the concentration and pH range of the homogeneous solution at a given mixing temperature were determined. The results were useful for creating injection-ready drug forms based on N-vinylpyrrolidone and 2-methyl-5-vinylpyridine copolymers.