Excretion of sodium 2-mercaptoethanesulphonate (MESNA) in the urine of volunteers after oral dosing

Quantification of BNP7787 (dimesna) and its metabolite mesna in human plasma and urine by high-performance liquid chromatography with electrochemical detection

A sensitive and accurate assay was developed and validated to determine BNP7787 (dimesna), a new protector against cisplatin-induced toxicities, and its metabolite mesna in plasma and urine of patients. Both analytes were measured as mesna in deproteinized plasma or in urine diluted with mobile phase using high-performance liquid chromatography with an electrochemical detector provided with a wall-jet gold electrode. The assays for BNP7787 and mesna in deproteinized plasma were linear over the range of 1.6-500 microM and 0.63-320 microM, respectively. In plasma, the mean recovery of BNP7787 over the whole concentration range was 100.6% and of mesna 94.6%. The lower limits of quantitation (LLQs) of BNP7787 and mesna in deproteinized plasma were 1.6 microM and 0.63 microM, respectively. For both compounds the within- and between-day accuracy and precision of the assay was better than 12%. The assays for BNP7787 and mesna in urine were linear over the range of 0.8-1200 microM and 0.63-250 microM, respectively. In urine, the mean recovery of BNP7787 over the whole concentration range was 94.1% and of mesna 93.1%. The LLQ of BNP7787 in urine was 0.8 microM and of mesna 1.6 microM. The within- and between-day accuracy and precision of the assay for BNP7787 and mesna was lower than 15%. The stability of mesna in urine increased with an increasing concentration of mesna, lower temperature and addition of EDTA (1 g/l) and hydrochloric acid (0.2 M). BNP7787 in urine was stable for at least 24 h at temperatures in the range of -20 degrees C up to 37 degrees C and independent of the concentration. The developed assays are currently applied for samples of patients with solid tumors participating in a phase I trial of BNP7787 in combination with cisplatin.

Pharmacokinetics of mesna and dimesna after simultaneous intravenous bolus and infusion administration in patients undergoing bone marrow transplantation

This study was undertaken to examine the pharmacokinetics of mesna and its dimer form, dimesna, in the plasma and urine of patients undergoing bone marrow transplantation who received 130 mg/kg of mesna divided intravenously into a 30-mg/kg bolus dose followed immediately by 100 mg/kg infused over 12 hours for uroprotection. The relationship between and urinary excretion of mesna and dimesna also was examined by comparing the data obtained in patients who developed hemorrhagic cystitis versus those who did not. Blood and urine samples were collected at different time intervals after administration, and the plasma or urine was analyzed by liquid chromatography with electrochemical detection. Dimesna was analyzed in these samples after reduction back to mesna with sodium borohydride. The concentration-time data of mesna exhibited the characteristics of the two-compartment model well, and the mean +/-SD values of the distributive phase half-life (t1/2 alpha), postdistributive phase half-life (t1/2 beta), volume of distribution of the central compartment (Vdc), volume of distribution at steady state (Vdss), volume of distribution during the postdistributive phase (Vd beta), total clearance (Cl), and mean residence time (MRT) observed were 0.12 +/- 0.15 hours, 2.12 +/- 1.61 hours, 0.324 +/- 0.336 L/kg, 1.09 +/- 1.18 L/kg, 2.09 +/- 3.0 L/kg, 0.755 +/- 0.507 L/hr.kg, and 6.77 +/- 0.72 hours, respectively. The mean +/-SD values of t1/2 and MRT of dimesna were 1.29 +/- 0.6 hours and 6.68 +/- 1.05 hours, respectively, and the ratio of the area under the concentration-time curve (AUC) of mesna to that of dimesna was 1.21 +/- 0.57. The fractions of dose excreted in urine in the form of mesna and dimesna in 20 hours (fu) were 0.361 +/- 0.15 and 0.482 +/- 0.25, and the renal clearance (ClR) values were 0.244 +/- 0.201 L/hr.kg and 0.157 +/- 0.156 L/hr.kg, respectively. The urinary excretion of mesna in these patients was higher than that required for uroprotection for the whole duration of infusion, and there was no significant difference in the pharmacokinetics of mesna between patients who developed hemorrhagic cystitis and those who did not. This was not the case with dimesna, in which patients with hemorrhagic cystitis excreted in urine less than 50% of the amount of dimesna excreted by those without hemorrhagic cystitis.

Phase II clinical trial of carboplatin, ifosfamide, with oral mesna for metastatic breast carcinoma

Twenty-five women with advanced breast carcinoma refractory to first-line chemotherapy entered a phase II trial to evaluate the efficacy of ifosfamide and carboplatin. Additionally the trial assessed the clinical usefulness of oral 2-mercaptoethane sulfonate (mesna) for urothelial protection. Two partial remissions were observed (8%); toxicity was significant but acceptable, with no treatment-related deaths. The combination of ifosfamide and carboplatin had little activity as the second-line treatment in our population of patients with heavily pretreated metastatic breast cancer. Oral mesna was effective for urothelial protection, permitting outpatient administration of ifosfamide.

Depletion of circulating cyst(e)ine by oral and intravenous mesna

The sulfhydryl status of normal and tumour cells is critically important in determining their susceptibility to various cytostatic agents. As a sulfhydryl compound, mesna (sodium 2-mercaptoethane-sulfonate) which is used in large doses to prevent haemorrhagic cystitis associated with certain chemotherapeutic regimens might derange cellular thiol homeostasis. In order to investigate the effects of mesna on the concentrations of thiols in plasma, cysteine, glutathione and their disulfides were measured by HPLC following the oral and intravenous administration of mesna to healthy volunteers. After 7.3 mmol mesna i.v. free cysteine rose from 8.2 (95% CI 7.0-9.4) nmol ml-1 to 53.6 (47.4-59.8) nmol ml-1 at 5 min, most likely due to reduction of circulating cystine by the sulfhydryl drug. This initial rise was followed by a marked decrease of total cyst(e)ine in plasma from 276 (215-337) nmol ml-1 to a nadir of 102 (89-115) nmol ml-1 between 30-120 min after infusion, most likely due to an increased uptake of cysteine into cells and an increased urinary excretion of cyst(e)ine. Qualitatively similar changes were seen after oral mesna. The present data indicate that mesna depletes circulating cyst(e)ine and may thereby markedly alter the sulfhydryl status of cells in vivo although the drug itself is not taken up by most cells.

Oral bioavailability of mesna tablets

To test the feasibility of uroprotection with sodium 2-mercaptoethane-sulfonate (mesna) in tablet form the bioavailability of mesna tablets was determined in healthy volunteers by HPLC. The area under the plasma concentration-time curve (AUC) of free mesna was significantly lower following oral (110 mumol.l-1 x h-1; 95% CI 98-122) than following i.v. administration of 1.2 g of mesna (201 mumol.l-1 x h-1; 95% CI 158-244). The AUC for total mesna, i.e. dimesna and mixed disulfides, however, were comparable in the two groups, with 628 (539-717) and 772 (713-831) mumol.l-1 x h-1, respectively. The mean residence time was significantly longer following oral mesna, at 79 (76-83) min vs 239 (229-250) min. Following oral mesna 51.1% (46.2-56.0%) of the administered dose was recovered in the urine in 24 h, compared with 60.6 (53.6-67.6)% in 4 h following i.v. mesna, and the average concentration of mesna in the urine exceeded 3 mmol.l-1 for 8 h. The data indicate that mesna in tablet form has an adequate bioavailability for uroprotection and therefore may be preferable to liquid mesna, which has an unpleasant taste. Oral mesna has a longer mean residence time than i.v. mesna, which means that uroprotection can be achieved with longer dosing intervals.

Feasibility and efficacy of arginine 2-mercaptoethanesulfonate (ARGIMESNA) in the prevention of hemorragic cystitis from ifosfamide (IFO)

Tolerability and efficacy of the new uroprotective agent ARGIMESNA was assessed within a randomized cross-over study comparing it to sodiummercaptoethanesulfonate (MESNA), in patients treated with IFO. MESNA i.v., 20% of IFO dose, was given to all patients before chemotherapy; 4 h later, at random, they received ARGIMESNA p.o., 20% of IFO dose every 2 h x 4, or MESNA p.o., 40% of IFO dose every 4 h x 2. Overall, 78 cycles of oral uroprotection were administered: 37 for ARGIMESNA capsules; 41 for MESNA vials p.o. ARGIMESNA was subjectively better tolerated, determining gastro-intestinal discomfort in only 12 out of 37 cycles versus 34/41 of MESNA p.o. (p less than 0.001). Both preparations were equivalent for subjective and objective efficacy since no cycles were complicated by urinary symptoms (dysuria, stranguria, or hematuria). Nevertheless, 2 patients (7.7%) refused further oral assumption of both uroprotectors, whereas MESNA i.v. was added in other 7 patients because of nausea and vomiting caused by chemotherapy. In conclusion, this new oral preparation of mercaptoethanesulfonate turned out to be well tolerated, safe and active in the prevention of haemorrhagic cystitis from IFO.

False-positive ketone tests: a bedside measure of urinary mesna

The sulfhydryl mesna is increasingly used to protect the bladder and kidney from effects of chemotherapy with ifosfamide and cyclophosphamide. Mesna reacts with reagents on urinary test strips designed to detect ketones. Test-strip results were correlated to sulfhydryl concentrations in 931 urine specimens obtained after infusions of mesna. These data may be used to estimate urinary mesna concentrations at the bedside or to test compliance in outpatients given oral mesna therapy.

Excretion of disodium bis-2-mercaptoethanesulphonate (dimesna) in the urine of volunteers after oral dosing

Dimesna was given to volunteers (n = 6) and levels of free thiols, mesna, cysteine and disulphides measured in urine. Mesna is excreted in the urine following oral dimesna administration. Peak urinary free thiol levels occur between 10 and 20 hr. Cysteine and mixed disulphides are also excreted. Mesna might be useful in prolonged bladder protection during oxazaphosphorine cancer chemotherapy.

Pharmacokinetics of intravenous and oral sodium 2-mercaptoethane sulphonate (mesna) in normal subjects

The pharmacokinetics of mesna (sodium 2-mercaptoethane sulphonate) and its inactive disulphide, dimesna, were investigated using high performance liquid chromatography in six normal subjects following intravenous and oral administration of 800 mg mesna. The mean maximum mesna concentration after i.v. administration was 111 (s.d. +/- 28.3) nmol ml-1 and the mean maximum dimesna concentration was 183 (s.d. +/- 41.6) nmol ml-1. Following oral mesna dosing the mean peak mesna concentration was 19.6 (s.d. +/- 10.2) nmol ml-1 but mesna was only found in the plasma of five of the six subjects. The mean peak dimesna concentration was 22.5 (s.d. +/- 12.4) nmol ml-1. Following i.v. mesna administration, the mean half-life of mesna was 21.8 (s.d. +/- 3.1) min and total body clearance 1.23 (s.d. +/- 0.31) l kg-1 h-1. The mean half-life of dimesna was 1.17 (s.d. +/- 0.32) h. It was not possible to determine their half-lives after oral mesna administration. The mean mesna concentration in the 0-4 h urine collection was 9.6 (s.d. +/- 10.7; range 1.4-28.7) nmol ml-1 following i.v. mesna injection. After oral mesna the highest mesna concentration occurred in either the 0-4 or 4-8 h urine collections. The mean peak mesna concentration was 2.5 (s.d. +/- 1.7) mumol ml-1 (c.f. estimated uroprotective concentration of 1.7 mumol ml-1). The mean 4 h urinary clearance of the uroprotective species mesna was 0.413 (s.d. +/- 0.136) l kg-1 h-1. After both i.v. and oral mesna the urinary excretion of mesna is predominantly during the first 4 h.(ABSTRACT TRUNCATED AT 250 WORDS)

The stability of mesna in beverages and syrup for oral administration

We evaluated the stability of the aqueous formulation of mesna during storage in syringes and after dilution in beverages and syrups. Measurements of the concentrations of mesna showed that the undiluted formulation was stable for at least 9 days in standard polypropylene syringes at 5 degrees, 24 degrees, and 35 degrees C. There was no detectable oxidation of mesna to dimesna over the course of at least 1 week when mesna was diluted 1:2 and 1:5 in syrups and incubated at 24 degrees C in capped tubes. Concentration changes were clinically negligible for 1:2, 1:10, and 1:100 dilutions of mesna in six carbonated drinks, two juices, and milk after incubation for 24 h at 5 degrees C. Thus, the aqueous mesna formulation is stable when diluted and stored in a variety of beverages and syrups under conditions suitable for oral administration.