RE-EVALUATION OF PH AND TONICITY OF PHARMACEUTICAL BUFFERS AT 37 DEGREES

Commonly employed isotonic buffer mixtures of pharmaceutical interest were studied at body temperature with emphasis placed on the tonicity and pH of these preparations. Tonicity data interpreted from vapor pressure osmometer data are presented for the official phosphate buffers, boric acid buffer, and Palitzsch buffers. Human serum was also checked at this temperature to validate the accepted base line of 0.90% as being isoosmotic with body fluids. Interesting discrepancies between freezing point depression data and vapor pressure osmometer data are discussed. Reformulated isotonic Palitzsch and boric acid buffers at 37° are presented. A critical assessment of accepting tonicity values at 0° and extrapolating them to body temperature is attempted. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company