Sodium salicylate Probenecid

A reversed-phase HPLC post-column ion-pair extraction system was developed by Kim and Stewart [71, 72] for the analysis of carboxylic acid drugs and their salts (sodium formate, sodium acetate, 3-bromopropionic acid, 6-aminocaproic acid, 11-bromoundecanoic acid, 1-heptanesulfonic acid, / -n i t rophcny 1 acetic acid, sodium benzoate, sodium salicylate, valproic acid, probenecid, naproxen, ketoprofen, ibuprofen, mefenamic acid, flufenamic acid, and cefuroxime sodium) using a-(3,4-dimethoxy-phenyl)-4,-trimethylammoniummethylcinnamonitrile methosulfate... 

The amount of urate bound in the absence of drugs was regarded as the baseline and the amounts bound in the presence of various drugs were expressed as percentages of the control values (Fig. 2). It can be seen that probenecid, sulfinpyrazone and sodium salicylate all significantly displaced urate from human albumin binding sites, while colchicine had no effect. 

Ethambutol had no effect on the urinary excretion of sodium or potassium and there was no clinical evidence of volume depletion in patients receiving this agent. The hyperuricemia of ethambutol was not reversed by salicylates in 3 patients in whom this was studied. Ethambutol did not inhibit the effect of probenecid, sulfinpyrazone or iopanoic acid in 3 additional patients. 

Let s now study the titrations of the carboxylic acids that are too poorly soluble in water and therefore necessitate the use of mixtures of water and organic solvents. The most commonly used mixtures are the hydroalcoholic ones. Ethanol must be neutralized by a sodium hydroxide solution before being mixed with water. Benzoic, undecyienic, etacrinic, and salicylic acids as well as probenecid (Fig. 11.4) are titrated according to this methodology. 

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