SYNTHESIS AND INVESTIGATION OF THE PROPER TIES OF WATER-SOLUBLE COPOLYMERS OF N-VINYL-2-PYRROLIDONE WITH CROTONIC ESTERS OF CORTICOSTEROIDS

Hydrocortisone, prednisolone, and dexamethasone 21-crotonates were syn thesized. Water-soluble copolymers with steroid content up to 4 or 5 m ol % and with an intrinsic viscosity of 0.07 - 1.2 dl g-1 in methanol were prepared by copolymerization with N-vinyl-2-pyrrolidone. The hydr olytic stability of the copolymer of N-vinyl-2-pyrrolidone and hydroco rtisone 21-crotonate was studied. It was shown that the copolymer is r elatively stable at pH 5 - 7 and releases steroid rapidly at pH 9. The state of macromolecules in methanol and water was characterized by po larized luminescence and viscometric technique. The data obtained sugg est that macromolecules become more compact in water owing to hydropho bic interactions of steroid fragments.