Abstract
Coating processes of coconut and pitch base spherical activated charcoal (CAC and PAC) with poly (2-hydroxyethyl methacrylate) (poly-HEMA) were studied to make good adsorbent suitable for direct hemoperfusion (DHP). Improvement of blood compatibility and prevention of microparticle release were the main purpose of encapsulation. Decrease of the activity must be minimized by coating. Encapsulation of activated charcoal (AC) with the monomer (HEMA), prepolymerized HEMA or purified poly-HEMA, in 95% ethanol solution was evaluated by comparing the creatinine adsorption rates of the coated AC. PAC coated with 1-% poly-HEMA solution adsorbed creatinine as quickly as the oiginal AC. Microparticle release from AC was completely prevented by double coating with 0.1 and 1% poly-HEMA solution and 12-time washings. Permeation resistance of coated layer against rather high molecular weight solutes was observed but the amounts of solutes adsorbed by the coated charcoal during a period of 2 h were nearly the same as those done by the uncoated one. It is suggested that pressure drop in a 200ml column containing double-coated PAC and platelet counts at the inlet and outlet did not change throughout the 2 h DHP in in vivo studies. The poly-HEMA-coated PAC can be a promising adsorbent for metabolites and poisons in living bodies and is readily introduced into the clinical application.
