1-salicylate-glucuronide and salicylurate

Acetylsalicylic acid (Aspirin, ASA) is a famous drug for cardiovascular diseases in recent years. Effects of ASA dosage on the metabolic profile have not been fully understood. The purpose of our study is to establish a rapid and reliable method to quantify ASA metabolites in biological matrices, especially for glucuronide metabolites whose standards are not commercially available. Then we applied this method to evaluate the effects of ASA dosage on the metabolic and excretion profile of ASA metabolites in rat urine. Salicylic acid (SA), gentisic acid (GA) and salicyluric acid (SUA) were determined directly by UHPLC-MS/MS, while salicyl phenolic glucuronide (SAPG) and salicyluric acid phenolic glucuronide (SUAPG) were quantified indirectly by measuring the released SA and SUA from SAPG and SUAPG after β-glucuronidase digestion. SUA and SUAPG were the major metabolites of ASA in rat urine 24h after ASA administration, which accounted for 50% (SUA) and 26% (SUAPG). When ASA dosage was increased, the contributions dropped to 32% and 18%, respectively. The excretion of other three metabolites (GA, SA and SAPG) however showed remarkable increases by 16%, 6% and 4%, respectively. In addition, SUA and SUAPG were mainly excreted in the time period of 12-24h, while GA was excreted in the earlier time periods (0-4h and 4-8h). SA was mainly excreted in the time period of 0-4h and 12-24h. And the excretion of SAPG was equally distributed in the four time periods. We went further to show that the excretion of five metabolites in rat urine was delayed when ASA dosage was increased. In conclusion, we have developed a rapid and sensitive method to determine the five ASA metabolites (SA, GA, SUA, SAPG and SUAPG) in rat urine. We showed that ASA dosage could significantly influence the metabolic and excretion profile of ASA metabolites in rat urine.

Topics: Animals; Aspirin; Chromatography, High Pressure Liquid; Glucuronates; Glucuronidase; Glucuronides; Hippurates; Male; Metabolome; Rats; Rats, Sprague-Dawley; Salicylates; Salicylic Acid; Tandem Mass Spectrometry

A novel direct high-performance liquid chromatographic (HPLC) assay for the simultaneous determination of three salicylate glucuronide conjugates and other salicylate metabolites in human urine has been developed. Salicylate glucuronide conjugates were purified by HPLC from the urine of a volunteer after oral administration of aspirin and identified by selective hydrolysis with beta-glucuronidase and with sodium hydroxide. This method gave high reproducibility with coefficients of variation less than 10%. The total urinary recovery of salicylic acid after a single 1.2-g dose of soluble aspirin was greater than 90%. This assay has been successfully used to re-evaluate the capacity-limited pharmacokinetics of salicylic acid in humans.

Topics: Administration, Oral; Aspirin; Chromatography, High Pressure Liquid; Glucuronates; Hippurates; Humans; Salicylates

Homeostasis of inorganic sulfate, a physiologic anion necessary for both detoxification and biosynthetic reactions, involves predominantly capacity-limited renal clearance mechanisms. The objective of this investigation was to examine the effect of salicylic acid (SA) and its major metabolites, salicyluric acid and salicyl phenolic glucuronide, on the serum concentrations and renal clearance of inorganic sulfate in rats. Animals were studied using a crossover design in which they received a bolus i.v. injection (75 mg/kg) and infusion (approximately 0.26 mg/min/kg) of SA or the same volume of saline (the vehicle). Blood samples were collected at 2, 3 and 4 hr after administration and urine between 2 and 4 hr. The renal clearance of sulfate and creatinine were examined at mean steady-state SA serum concentrations of 249 micrograms/ml. Although no changes in the serum concentrations and renal clearance of creatinine were observed, the renal clearance of inorganic sulfate was increased significantly (2.13 +/- 0.74 vs. 1.09 +/- 0.54 ml/min/kg in controls, mean +/- S.D., n = 7) and its serum concentration decreased (0.55 +/- 0.12 vs. 1.04 +/- 0.23 mM in controls). These changes were not due to alterations in uric acid concentrations as uric acid serum concentrations and renal clearance were unchanged when examined at similar steady-state SA serum concentrations in a subsequent study. The effects on sulfate disposition also were probably not due to the major metabolites of SA: no changes in the serum concentrations or renal clearance of sulfate were observed at mean steady-state concentrations of 52 micrograms/ml of salicyluric acid or 73.7 micrograms/ml of salicyl phenolic glucuronide after their direct administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Biological Transport; Female; Glucuronates; Hippurates; Homeostasis; Kidney; Metabolic Clearance Rate; Rats; Rats, Inbred Strains; Salicylates; Salicylic Acid; Sulfates

Indirect measurement of salicylphenolic glucuronide (SPG) has suggested that the formation of this metabolite from therapeutic doses of salicyclic acid (SA) is capacity-limited in humans. A direct high performance liquid chromatographic (HPLC) assay for SPG in human urine is described. SPG was prepared by a published method and purified by HPLC. On treatment with beta-glucuronidase, SPG yielded the expected amount of SA. Spectroscopic data, melting point, and optical rotation of the glucuronide and/or its triacetyl dimethyl ester derivative were consistent with the proposed structure. SPG was assayed using a 5-micron C18 column (temperature 55 degrees C) and fluorescence detection. A nonlinear gradient mobile phase at a flow rate of 2 ml/min was used, beginning with 100% 0.1 M pH 2.1 phosphate buffer and finishing with 84% buffer, 16% acetonitrile. Total run time was 25 min. Urine (10 microliter) was injected directly on the column, and quantitation was performed using urine standards. Within-run precision for SPG ranged from 1.2% at 150 mg/L to 2.4% at 5 mg/L. The limit of detection was less than 1 mg/L. A pilot study in two volunteers, each receiving a single 500-mg dose of sodium salicylate, was carried out to validate the usefulness of the assay.

Topics: Adult; Chromatography, High Pressure Liquid; Gentisates; Glucuronates; Hippurates; Humans; Hydrogen-Ion Concentration; Hydroxybenzoates; Kinetics; Magnetic Resonance Spectroscopy; Salicylates; Salicylic Acid