Determination of galactosamine impurities in heparin sodium using fluorescent labeling and conventional high-performance liquid chromatography

Heparin is a sulfated glycosaminoglycan (GAG), which contains N-acetylated or N-sulfated glucosamine (GlcN). Heparin, which is generally obtained from the healthy porcine intestines, is widely used as an anticoagulant during dialysis and treatments of thrombosis such as disseminated intravascular coagulation. Dermatan sulfate (DS) and chondroitin sulfate (CS), which are galactosamine (GalN)-containing GAGs, are major process-related impurities of heparin products. The varying DS and CS contents between heparin products can be responsible for the different anticoagulant activities of heparin. Therefore, a test to determine the concentrations of GalN-containing GAG is essential to ensure the quality and safety of heparin products. In this study, we developed a method for determination of relative content of GalN from GalN-containing GAG in heparin active pharmaceutical ingredients (APIs). The method validation and collaborative study with heparin manufacturers and suppliers showed that our method has enough specificity, sensitivity, linearity, repeatability, reproducibility, and recovery as the limiting test for GalN from GalN-containing GAGs. We believe that our method will be useful for ensuring quality, efficacy, and safety of pharmaceutical heparins. On July 30, 2010, the GalN limiting test based on our method was adopted in the heparin sodium monograph in the Japanese Pharmacopoeia.

[Comparison of positivity between density gradient centrifugal method and whole blood method in lymphocyte surface marker analysis with flow-cytometry]

The lymphocyte surface marker analysis with flow-cytometry is usually performed using a density gradient centrifugal method or a whole blood method. We have compared these two methods using several monoclonal antibodies and have found the significant difference in positivity all monoclonal antibodies except TCR-1 (anti alpha/beta receptor on T-lymphocyte). We found the significantly higher positivity of Leu12 and HLA-DR as well as lower of the other monoclonal antibodies by using whole blood method than by density gradient centrifugal method. We conclude that it is necessary to make a distinct description of the method used in the surface marker analysis.

Intestinal absorption of salicylamide and effect of atropine on it

The effect of atropine (ATR), a parasynpatholytic agent, on the intestinal absorption of salicylamide (SAM) was studied using the absorption kinetic model proposed by Winne et al. The disappearance of SAM from perfusate and the appearance in intestinal blood were determined using perfused intestinal loop of the rat in vivo. The results showed that the absorption of SAM was simulated by the four compartment model consisting of luminal, interstitial, blood and serosal compartments. The model was assumed to have three rate determining factors, namely mucosal membrane permeability, clearance by blood flow and serosal membrane permeability. ATR decreased the absorption of SAM by decreasing the clearance factor relating to intestinal blood flow and increased the fraction of the transported amount of SAM from interstitial space to serosal compartment.