The biological evaluation of unfractionated heparins was carried out against the 5th International Standard of porcine heparin using the pharmacopoeial-recommended assays: the sheep plasma coagulation inhibition assay (SPCIA), activated partial thromboplastin time (APTT) and anti-factor Xa activity. The SPCIA method gave mean potencies which were 10.72% significantly higher than the other procedures. The effect of differences in plasma batches revealed potency variations of up to 7.32%. The anti-factor IIa assay was standardized as an alternative method for the potency assessment of heparin samples. The values obtained were in good agreement with the anti-factor Xa assay results, demonstrating the feasibility of the method as a harmonized assay for the quality control of medicines. Analysis of the potency estimates showed that generally batch-to-batch variations complied with pharmacopoeial specifications, demonstrating the overall quality of the products and assuring their safety and clinical efficacy.
Heparins; sheep plasma; anti-factor Xa; activated partial thromboplastin time; anticoagulant; anti-factor IIa
