Chemical Formula: B1a：C50H77NO14 B1b：C49H75NO14 Molecular weight: B1a:916； B1b:902 Character: White or yellowish-white, crystalline powder, soluble in acetone and in methanol, insoluble in water. Standard: Eprinomectin H2B1a + H2B1b not less than 95.0%(anhydrous and solvent-free substance). Ratio H2B1a/H2B1a+ H2B1b minium 90.0%. Storage: Store in an airtight container, protected from light. Period of Validity: Two Year Packing: 1kg/Tin,5kg/Tin