Biological and Pharmacological Profiling of Pentosan Polysulfate (PPS) in Comparison to Heparin and its Relative Neutralization by Protamine Sulfate

Abstract

BackgroundPentosan Polysulfate has traditionally been used to treat patients with Interstitial Cystitis and more recently osteoarthritis, cancer, HIV and prion disease. Such widespread clinical application of PPS and the active search for new effective alternatives to traditional heparin compels a comprehensive investigation of the effect of PPS batches on anticoagulation in comparison to Heparin. The purpose of this study is to create a comprehensive profile and comparison of new PPS batches (L‐15, L‐19, L20 and Ba), old PPS batch (PPS Ba), and Heparin. Furthermore, the feasibility of protamine sulfate as a neutralizing agent to reverse the anticoagulant effects of PPS is investigated.Materials and MethodsVarious batches of PPS at 1 mg/ml were prepared in saline. For whole blood clotting profile, thromboelastography (TEG) was carried from 2.5 – 5.0 ug/ml and activated clotting time (ACT) at 25ug/mL. Clotting profile in whole blood, retrieved plasma and supplementation in normal human pooled plasma (NHP) were carried out at 100 – 0.0 ug/ml by using anticoagulant assays. Amydolytic methods were used to measure anti‐Xa/ IIa effects. Thrombin generation inhibition studies (TGA) were carried out in NHP from 100 ‐ 0.0 ug/ml. Heparin supplementation and protamine sulfate neutralization in NHP from 10 ‐0 ug/mL were compared to PPS batches in a logarithmic scale.ResultsAll drugs produced a concentration dependent effect. Similar effects in anticoagulation assays were noted except anti‐Xa assay. In TEG, significant viscoelastic changes were observed at 5ug/mL. Prolongation of ACT was observed at 25ug/mL. No significant differences were noted in between batches of PPS in TEG and ACT studies. In TGA, concentration dependent but no significant difference in between the batches were noted. Neutralization of protamine sulfate was observed up to 12.5 ug/mL in anticoagulant assays and marginal effect on anti‐protease assays. Lastly, logarithmic comparison of the protamine sulfate neutralization indicated that protamine sulfate is a weaker neutralizing agent of PPS compared to heparin.ConclusionThese studies suggest that multiple batches of PPS have a similar anticoagulant profile. In comparison to heparin, PPS presents itself as a 10‐fold weaker anticoagulant alternative for use in a variety of clinical applications. Neutralization of PPS at low concentrations by protamine sulfate in anticoagulant assays warrants further investigation on an effective neutralizing concentration for clinical use.