Tobin T, Tai C Y, Arnett S
Res Commun Chem Pathol Pharmacol. 1975 Jun;11(2):187-94.
A published method for the recovery of procaine from human plasma using 5M NaOH gave very poor recoveries. Investigation showed that under the recommended extraction conditions procaine was rapidly hydrolysed. Extraction into benzene of samples buffered to pH 9.0 with borate buffer allowed essentially 100% recovery of procaine from equine plasma and urine.
