Patent ID: 8268790

Claim:
A process for the preparation of an aqueous gel preparation comprising at least 30% by weight water together with a polymeric combination of clindamycin phosphate and a water-soluble Zn 2+ salt, the clindamycin phosphate being predominantly in Zwitterionic form with a deprotonated phosphate group and a protonated tertiary amine of the clindamycin phosphate, said Zwitterionic clindamycin phosphate being complexed to Zn 2+ , the process comprising: providing a mixture of clindamycin phosphate with a liquid that includes at least 30% water by weight; adjusting the pH of the mixture to a pH above 7 and less than 8; adding a Zn 2+ salt to form said polymeric combination of zwitterionic clindamycin phosphate and Zn 2+ .