| abstract |
The present invention relates to a process for the preparation of crystalline non-hygroscopic form H1 of efavirenz, and pharmaceutical compositions containing it. In accordance with the present invention efavirenz was dissolved in acetone at 25 °C - 30°C, the solution was slowly added to water at O °C - 5 °C, the separated solid was filtered, washed with mixture of acetone and water and dried at 25 °C - 35 °C under below 65 % relative humidity for 18 hours to give crystalline non-hygroscopic efavirenz form H1. |