It was proposed that middle mollecular weight compound (350-5000 daltons)may present :part of the toxic molecules responsible for uremic patients.In bilateral nephrectomy rat model

the serum middle molecules increased markedly.Agarose encapsulated charcoal (CAAC Ⅱ)as we- 11 as albumin collodion coated active charcoal (ACAC) and uncoated charcoal were used as adso- rbents during hemoperfusion.All kinds of charcoal can adsorb middle molecules both in vitro and in vivo.The CAAC Ⅱ can adsorb more middle molecules than the uncoated one

becuase the larger molecules cannot pass the encapsulated membrane of the former and spared more spa- ce for adsorbing MM.