Determination of meperidine blood to plasma concentration ratio (lambda) - effect of temperature and pH.

The blood to plasma concentration ratio (lambda) for meperidine was found to be temperature and pH dependent but independent of concentration. lambda values at room temperature were significantly lower than those at 37 degrees C (p less than .01). Decreasing the blood pH within the range 7.2 to 6.9 resulted in a significant decrease in lambda (p less than .01).