Patent ID: 8536151

Claim:
A process for preparation of lamivudine polymorph form I, which comprises: a) dissolving lamivudine in alcohol; b) refluxing for about 30 minutes to 45 minutes; c) cooling to about 0° C. to 10° C.; d) maintaining for about 1 hour to 1 hour 30 minutes at about 0° C. to 10° C.; e) filtering the solid separated and washing with alcohol; f) drying the material at 60° C. to 70° C. ; g) dissolving the solid obtained in a mixture of an alcohol and a water; h) heating to 40° C. to 45° C. for about 30 minutes to 45 minutes; i) cooling to about 25° C. to 35° C.; j) maintaining for about 1 hour 30 minutes to 2 hours at about 25° C. to 35° C.; and k) filtering the solid separated and drying the material at 45° C. to 50° C. to form lamivudine polymorph form I, wherein the alcohol is selected from methanol, ethanol, isopropyl alcohol, tertbutyl alcohol and n-butyl alcohol; or mixture thereof.