Patent ID: 6861412

Claim:
A method of making a liquid crystal or crystalline polymorph of (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[[2,6-dideoxy-3-C-methyl-3-O-methyl-4-C-[(propylamino)methyl]-α-L-ribo-hexopryanosyl]oxy]-2-ethyl-3,4,10-trihydroxy-3,5,8,10,12,14-hexamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one diphosphate having the formula wherein n is 0 to 8 comprising dissolving (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[[2,6-dideoxy-3-C-methyl-3-O-methyl-4-C-[(propylamino)methyl]-α-L-ribo-hexopryanosyl]oxy]-2-ethyl-3,4,10-trihydroxy-3,5,8,10,12,14-hexamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one in absolute ethanol at ambient temperature; adding a solution of phosphoric acid in absolute ethanol over about 2 to 5 minutes; partially dissolving the resulting solid by addition of water; collecting the resulting crystal crop at ambient temperature; and rinsing said crystal crop with several small portions of about 10/1 (v/v) ethanol-water.