A Comparative Study of Various Compendial Biuret Methods for Estimation of Protein in Human Biologicals

Blood products laboratory is a Central Drug Testing Laboratory for testing quality standards of plasma-derived products in India. Blood products laboratory received 243 batches of human normal albumin during the financial year 2015-16 from indigenous and international manufacturers for testing. As per Indian Pharmacopoeia, the biuret method is different from European and British Pharmacopoeia for protein estimation, therefore, harmonisation of a such method is necessary as per World Health Organization’s recommendation. In this context, blood products laboratory conducted a comparative study between the methods of Indian, European and British Pharmacopoeia for protein estimation in biologicals, especially for human albumin preparation to prevent any bias regarding protein content between indigenous samples and imported products. Results showed that both the methods were significantly not different (p=0.05), and also showed that Indian Pharmacopoeial biuret method was more sensitive although reagent stability was lower than that of European and British Pharmacopoeial methods.