Molecular formula: C46H80N2O13,H3PO4 Molecular weight: 967.14 Structural formula: Item Standard ( According to USP27) Results Appcarance Primrose Yellow to Yellow Powder Almost white to Primrose Yellow Powder Color of 25% solution No requirement,usually Yellow to brown Primrose Yellow Total related substance(Calculated on the waterless substance) <=10.0% 7.0% - 9.0% Individual related substance(Calculated on the waterless substance) <=3.0% 2.0%-3.0% Water content <=5.0% 3.5% - 4.5% cis-isomer 82.0% - 88.0% 84.0%-86.0% trans-isomer 12.0% - 18.0% 14.0% - 16.0% heavy metal No test requirement <=20PPM content of Tilmicosin (Calculated on the waterless substance) >=75.0% >=77% PLC purity(Calculated on acreage Normalization method)