The hydroethylated amylopectins. Model substances comprising a two-variable system for the design of specific-acting volaemic colloids.

The requirement of volaemic colloids in specific-acting dosage forms, for utilisation in varied and numerous clinical applications, has led to the development of the hydroxyethylated and amylopectins (HESs). These glycogen-like substances comprise a two-variable drug design system, in which the interplay between the weight average molecular weight (Mw-) and the molar hydroxyethyl group substitution (MS) on the parent amylopectin molecule can be specifically adjusted to provide a family of volaemic colloids in short- to long-acting dosage forms. The MS however, appears to exert a finer mechanism of control on the intravascular persistence and the urinary excretion of the HESs in man. This can be seen to occur when assessing changes taking place in the molecular weight size distribution pattern in the bloodstream following injection. However, the Mw- must be considered in the design of HES drugs possessing specific effects on the suspension stability of blood.

Transfusion of hydroxyethylated amylopectin-protected frozen blood in man. I. Plasma clearance and renal excretion of the cryoprotectant.

In man following the autologous transfusion of blood previously frozen with 14% low molecular weight-hydroxyethylated amylopectin (cryo-HES), the clearance of this material from the intravascular space was compound, and appeared to consist of exponential components. The overall half-life -- however, was 10.6 +/- 3.0 (SD) h. Approximately 17% of the total infused cryo-HES was excreted in the urine 1 h postinjection, and 40% by 72 h. The erythrocyte sedimentation rate (ESR) was not affected by the presence of this substance in the bloodstream of the recipient. The results indicate that cryo-HES is removed rapidly following the transfusion of blood previously frozen with this material.