A series of polymers of polyglutamic acid have been tested as plasma volume expanders. The results indicate that those polymers prepared from backbones of 40,000 molecular weight or over and side chains of 3,000 molecular weight or over, will have plasma volume retention half-life of 15 hours or longer.
Measurements of the oncotic efficiency of these polymers in vivo indicated a blood stream fluid retention of approximately 51 ml./gm. of polymer. Similar measurements of polymer-serum albumin solutions in vitro showed a retention of 52 ml./gm. of polymer.
The clinical response to infusion of solutions of these polymers indicated no untoward pharmacological properties. Although the number of trials presented is too small for ultimate conclusion regarding either the physiological or clinical effects of these polymers, they do provide a strong indication of the desirability of further clinical testing of this polymer and a sound basis on which to plan the larger scale preparation of polymer. Both measures are currently under way.