Abstract: Following the Veterinary Pharmacopoeia of the People's Republic of China and The Compendium of Technical Guidelines for Research on Veterinary Drugs,the appearance,viscosity,pH,moisture,density,endotoxin,content and releated-substances tests were carried out on eprinomectin (EPR) extended-release injection agent to establish the quality standard and compare the pharmacological equivalence with the reference formulation.Content and related substances were determined on ZORBAX Eclipse Plus C18 column (2.1 mm×50 mm,1.8 μm),mobile phase:formic acid:water:acetonitrile (0.04 mL:40 mL:60 mL);Flow rate:0.4 mL/min;Detection wavelength:245 nm;Column temperature:35 ℃;Injection volume:2 μL.The pharmacological equivalence of the agent (f2 value) was calculated by comparing the release degree under the conditions of PBS buffer of 0.5% SDS at 37 ℃ and the rotation speed of 50 r/min.After testing,the appearance of EPR sustained-release injection agent was clear and transparent,the average relative viscosity was 46.45 mPa·s,the average pH was 6.88,the preparation did not contain water,the density was 1.13 g/cm³,the endotoxin met the limit of less than 0.1 EU/mL,the content was greater than the labeled value of 5%,the amount of the substance was less than 5%,the test results were all in line with the injectable preparation requirements.After 31 d of release under the same conditions,both self-research and the original EPR sustained-release injection agent release were more than 80%,and the f2 value of self-research and the original was more than 50.The test results of self-researched EPR sustained-release injection agent were all in accordance with the standard for injectable agents,and the self-researched and original EPR sustained-release injection agent were pharmacologically equivalent.

Key words: eprinomectin (EPR); quality standard; drug release; pharmaceutical equivalence