Protamine Sulfate Neutralization Profile of Various Dosages of Bovine, Ovine and Porcine UFHs and Their Depolymerized Derivatives in Non-Human Primates

Introduction: Currently used unfractionated heparins (UFHs) and low molecular weight heparins (LMWHs) are derived from porcine intestinal mucosa. However, heparins have also been manufactured from tissues of other mammalian species such as cow (Bovine) and sheep (Ovine). Protamine sulphate (PS) is an effective inhibitor of heparin and is used clinically to neutralize both LMWH and UFH. In this study, we determined the PS neutralization profile of these agents in non-human primate model using anti-Xa and anti-IIa methods. Material and Methods: UFHs obtained from bovine, ovine and porcine mucosal tissues and their respective depolymerized LMWHs were administered at both, gravimetric (0.5 mg/kg) and potency adjusted (100 U/kg) dosages regimen intravenously to individual groups of primates in cross over studies. PS was administered at a fixed dosage and the relative neutralization of these anticoagulants was measured utilizing amidolytic anti-Xa and anti-IIa methods. Results: These studies have demonstrated that, the equi-gravimetric dosages of BMH, PMH and OMH have comparable PS neutralization profiles. At potency adjusted dosages, all UFHs were completely neutralized by PS. Although comparable, the LMWHs were not fully neutralized by PS in both the anti-Xa and anti-IIa assays. PS was more efficient in neutralizing the anti-IIa effects of LMWHs. Conclusion: Heparins of diverse origins showed comparable neutralization profiles by PS in the amidolytic anti-Xa and anti-IIa assays.