Porcine and Ovine Mucosal Heparins and Their Depolymerized Derivatives Are Comparable in Contrast to Their Bovine Equivalents

Introduction Unfractionated heparin (UFH) and low molecular weight heparins (LMWH) are primarily derived from porcine mucosal tissue. Since technology to manufacture heparin has advanced and quality assurance practices are in place, improved products with higher potency and purity are now available. This study compares multiple individual batches of UFH obtained from bovine, ovine, and porcine tissues and their depolymerized products obtained by benzylation/alkaline hydrolysis, representing enoxaparin. Materials and Methods The molecular weight profiles of heparins and enoxaparins from various sources were determined using size exclusion chromography. Anticoagulant potency was measured using clot based methods such as aPTT and thrombin time. Antithrombin‐mediated anti‐Xa and anti‐IIa activities were measured in defined biochemical systems. Commercially obtained methods were used to determine the USP potency in terms of anti‐Xa and anti‐IIa activities (Hyphen Biomedical, Ohio, USA). The interaction of the heparins and enoxaparins with heparin induced thrombocytopenia (HIT) antibody was also investigated. Results The molecular profile of multiple batches of the bovine, ovine, and porcine heparins were comparable and ranged from 15–18 kDa. The global anticoagulant and amidolytic protease activities for the bovine heparin were consistently lower than porcine and ovine samples. In the purified system the porcine and ovine preparations consistently showed lower IC50 values for both the thrombin and Xa inhibition in contrast to the bovine heparin. Similar trends were observed in the anti IIa assays. The USP potency of 28 batches of porcine ranged from 170–210 U/mg and the 21 batches of ovine heparins exhibited comparable potencies in the range of 160–210 U/mL. The USP potency of 30 batches of bovine mucosal heparin was much lower and ranged from 110–140 U/mg. The anti‐Xa – IIa ratio for the porcine and ovine heparins were comparable. However, the anti‐Xa – IIa ratio of bovine heparin was somewhat lower. The ovine and porcine enoxaparins exhibited comparable potencies which ranged from 94–110 U/mg whereas bovine enoxaparin was slightly lower, ranging from 80–87 U/mg. However the anti‐Xa and anti‐IIa ratios of the enoxaparins derived from various species were comparable. In the HIT screening, there was no difference between the HIT responses in the heparins from different species. Similar results were obtained amongst enoxaparins of different origins. Conclusions These studies show that heparins from bovine, ovine, and porcine origin exhibit comparable molecular profiles. While the porcine and ovine heparins exhibit similar biological potencies, bovine heparin was found to be weaker. The enoxaparins derived from these species exhibit similar molecular profiles, but in functional assays, the bovine derived products were weaker. These results suggest that heparin and enoxaparin derived from ovine mucosal tissue exhibit comparable biosimilar profiles. However, the bovine heparins and enoxaparin derived from bovine mucosal tissues are somewhat weaker.