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Abstract
OBJECTIVE To study the renal excretion and kidney accumulation of pentamidine, a potentially nephrotoxic compound, in the isolated perfused rat kidney (IPK). MATERIALS AND METHODS IPK experiments (3-4 per treatment group) were conducted using male Sprague-Dawley rats (250-350 g). Dose proportionality studies were carried out over a pentamidine dosing range of 80-4000 microg, designed to target initial perfusate concentrations from 1 to 50 microg/mL. Separate interaction experiments were conducted between pentamidine (800 microg) and tetraethylammonium (dose 8000 microg) or dideoxyinosine (dose 80 microg). Inulin was used as a glomerular filtration rate (GFR) marker. Control (drug-naive) perfusions were also carried out. Pentamidine was analysed in perfusate, kidney and urine samples by HPLC. Inulin was measured by a colorimetric method. RESULTS Pentamidine CLR (1.1 +/- 0.6 to 0.05 +/- 0.03 mL/min) and excretion ratio (3.6 +/- 1.5 to 0.56 +/- 0.15) significantly decreased over the range of doses studied. Significant reductions in viability parameters (GFR, Na reabsorption) were noted in kidneys perfused with high dose pentamidine (4000 microg). Tetraethylammonium co-administration reduced pentamidine renal excretion, resulting in significantly greater kidney accumulation of pentamidine and reduced kidney function. Dideoxyinosine administration had minimal effects on pentamidine disposition. CONCLUSIONS Pentamidine renal transport involves a combination of mechanisms (filtration, secretion and passive reabsorption). Dose proportionality studies demonstrated non-linear excretion of pentamidine. Inhibition of pentamidine renal clearance by tetraethylammonium was consistent with decreased luminal transport. The detrimental effects of pentamidine on kidney function were the result of significant kidney accumulation of drug. The potential exists for drug-drug interactions between pentamidine and organic cations, increasing the risk of drug-induced nephrotoxicity.
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Affiliation(s)
- Nagaraju R Poola
- Division of Pharmaceutics and Industrial Pharmacy, Arnold & Marie Schwartz College of Pharmacy and Health Sciences, Long Island University, 75 DeKalb Avenue, Brooklyn, NY 11201, USA
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2
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Nordin J, Wikström I, Bronner U, Gustafsson LL, Ericsson O. Liquid chromatography-tandem mass spectrometry applied to a study of the metabolism of pentamidine. Discussion of possibilities and problems. J Chromatogr A 1997; 777:73-9. [PMID: 9297840 DOI: 10.1016/s0021-9673(97)00159-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tandem mass spectrometry is usually employed to achieve rapid screening or structure elucidation. We have used liquid chromatography-tandem mass spectrometry in order to detect metabolites of the antiprotozoal drug pentamidine in urine. Samples of urine from rat and man were analysed both by direct injection and after solid-phase extraction. The present paper discusses advantages and disadvantages of using direct injection of urine samples, optimization of chromatographic conditions with regard to the performance of the mass spectrometer, automation and stability of the entire system.
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Affiliation(s)
- J Nordin
- Department of Medical Laboratory Sciences and Technology, Karolinska Institute, Huddinge University Hospital, Sweden
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3
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Garzón MJ, Rabanal B, Ortiz AI, Negro A. Determination of pentamidine in serum and urine by micellar electrokinetic chromatography. J Chromatogr B Biomed Sci Appl 1997; 688:135-42. [PMID: 9029323 DOI: 10.1016/s0378-4347(97)88065-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A number of parameters influencing the electrokinetic processing of pentamidine by micellar electrokinetic chromatography (MEKC) were studied in order to develop an analytical method for this compound. The parameters considered were: pH, ionic strength, and SDS concentration of electrolyte, temperature and working voltage. On the basis of the results obtained, the best analytical conditions for the detection of pentamidine in serum and urine by MEKC were determined. Analysis by MEKC permitted determination of the drug in 10 min. Good linearity, reproducibility and accuracy were obtained in the range 0-30 micrograms/ml for both samples, with a correlation coefficient r > or = 0.9998 and a recovery of 87-92% in serum and 90-108.9% in urine. We examined the metabolism of pentamidine using rat liver homogenates in order to exclude any possible interference of metabolites in the analysis of pentamidine.
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Affiliation(s)
- M J Garzón
- Departamento de Bioquímica y Biología Celular, Universidad de León, Spain
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Bronner U, Ericsson O, Nordin J, Wikström I, Abdi YA, Hall JE, Tidwell RR, Gustafsson LL. Metabolism is an important route of pentamidine elimination in the rat: disposition of 14C-pentamidine and identification of metabolites in urine using liquid chromatography-tandem mass spectrometry. Pharmacol Toxicol 1995; 77:114-20. [PMID: 8584501 DOI: 10.1111/j.1600-0773.1995.tb00999.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This study assesses the contribution of metabolism for the disposition of pentamidine in the rat. With the use of 14C-labelled compound, the excretion of radioactivity in urine and faeces has been studied in four rats during 44 days after a single intravenous injection of the drug. The urinary and faecal excretion of the radioactivity were of equal importance; 22 +/- 2% (mean +/- S.D.) and 25 +/- 4% being detected in urine and faeces, respectively. The activity in organs and tissues at 44 days after drug administration was also measured and amounted to 21 +/- 5% of the administered dose. Using HPLC the proportion of metabolites in urine in relation to unchanged pentamidine increased with time after dose, being 76 +/- 15% (mean +/- S.D.) of the total excreted radioactivity on day 1 and 97 +/- 1% on day 6. HPLC--tandem mass spectometry was used for identification of metabolites in urine obtained from four rats given unlabelled pentamidine. Using synthetic reference compounds and the selective MS/MS mode four oxidized metabolites of pentamidine were identified either by direct injection into the system or by analyses of extracted urine. Thus, a substantial part of pentamidine is excreted as metabolites in urine.
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Affiliation(s)
- U Bronner
- Unit of Tropical Pharmacology, Karolinska Institute, Huddinge University Hospital, Sweden
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Bekersky I, Puhl RJ, Hanson G, Mong S. The pharmacokinetics of 1,3-di(4-imidazolino-2-methoxyphenoxy) propane.lactate (DMP.lactate), a new agent against opportunistic infections, in male beagle dogs. Drug Metab Dispos 1994; 22:233-6. [PMID: 8013279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The pharmacokinetics and oral bioavailability of 1,3-di(4-imidazolino-2-methoxyphenoxy) propane.lactate (DMP) was determined in male dogs following iv and po administrations of DMP.lactate containing trace amounts of [14C]DMP.HCl. Following the iv administration of [14C]DMP.lactate (2.5 mg/kg), plasma concentrations of DMP declined in a biexponential manner and were measurable to 48 hr. The terminal elimination half-life was 37.7 hr. The mean AUC0-infinity of DMP was 1.58 micrograms.hr/ml. The volume of distribution was 89 liters/kg and the body clearance was 27 ml/min/kg. The disposition of total radioactivity was similar to that of DMP. Approximately 14% of the dose was eliminated in urine as DMP or total radioactivity. Renal clearance was 10% of the body clearance. Following the po administration of [14C]DMP.lactate (14 mg/kg) the mean Cmax of total radioactivity and DMP was 0.20 and 0.17 micrograms/ml, respectively. The respective mean AUC0-T was 0.37 and 0.21 micrograms.hr/ml. The mean oral bioavailability based on DMP plasma concentrations was 2.4%. The mean Cmax of DMP following a 100 mg/kg po dose of DMP.lactate was 14 micrograms/ml and the AUC0-T was 1.87 micrograms.ml/hr; the bioavailability was 3.2%. Approximately 1% of the orally administered dose was eliminated in urine as DMP.
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Affiliation(s)
- I Bekersky
- Department of Pharmacology and Toxicology, Fujisawa Pharmaceutical Company, Deerfield, Illinois 60015
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Hanson GD, Slattum P, Tidwell RR, Bekersky I, Mong S. Determination of 1,3-di(4-imidazolino-2-methoxyphenoxy)propane in rat, dog and human plasma and urine by high-performance liquid chromatography with fluorescence detection. J Chromatogr 1993; 622:61-69. [PMID: 8120114 DOI: 10.1016/0378-4347(93)80250-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A sensitive and selective high-performance liquid chromatographic (HPLC) method was developed for the determination of 1,3-di(4-imidazolino-2-methoxyphenoxy)propane (DMP) in rat, dog and human plasma (50-5000 ng/ml) and urine (0.1-10 micrograms/ml). DMP and DMPent (dimethoxyimidizolinopentamidine, the internal standard), are extracted from alkanized plasma with n-butyl chloride-n-butanol (9:1, v/v). The organic phase is dried under nitrogen, reconstituted in mobile phase, and washed with hexane. Separation is achieved by ion-pair chromatography on a Zorbax Rx C8 column with fluorescence detection. The analysis of pooled plasma (80, 400, and 4000 ng/ml) and urine controls (0.3, 1.6, and 8 micrograms/ml) demonstrated excellent precision and accuracy over a three-day period. The recovery of DMP is > 90% from rat, dog, and human plasma and > 85% from rat and human urine, and 60-70% from dog urine. The limit of quantitation (LOQ) of the assay is 50 ng/ml in rat, dog and human plasma. Using the high-sensitivity assay, the limit of quantitation was decreased to 5, 2 and 0.6 ng/ml in rat, dog and human plasma, respectively. The LOQ of the assay is 0.1 microgram/ml in rat, dog and human urine. The assay was used to determine plasma and urine concentrations of DMP in pharmacokinetic studies in rat and dog.
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Affiliation(s)
- G D Hanson
- Hazleton Wisconsin, Department of Biopharmaceutics, Madison 53704
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Link H, Vöhringer HF, Wingen F, Brägas B, Schwardt A, Ehninger G. Pentamidine aerosol for prophylaxis of Pneumocystis carinii pneumonia after BMT. Bone Marrow Transplant 1993; 11:403-6. [PMID: 8504275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Following BMT there is a 5-15% risk of interstitial pneumonia caused by Pneumocystis carinii (PcP). Cotrimoxazole is therefore administered prophylactically, but may cause myelodepression, allergic reactions and nephrotoxicity. As PcP prophylaxis with pentamidine aerosol is effective in patients with AIDS, we conducted a prospective trial with regular inhalations of pentamidine. The aim of this study was to evaluate toxicity, safety, practicability and possible resorption of aerosolized pentamidine. We treated 31 allogeneic and 12 autologous BMT patients with 60 mg pentamidine 3 days before and 14 days after BMT. Starting 4 weeks after BMT, 300 mg pentamidine was given every 4 weeks for 6 months. There was no pneumonia caused by Pneumocystis carinii. The only noteworthy side-effects were cough (19.8%), salivation (9.6%), and sore throat (5.7%), of similar frequency after allogeneic or autologous BMT. Using high pressure liquid chromatography, pentamidine could only be detected in the serum of 33-54% of patients tested. In these patients the median serum levels were 7.5-9 ng/ml. We conclude that pentamidine aerosol has only minor side-effects, is well tolerated and safe, and is therefore an attractive alternative for PcP prophylaxis after BMT.
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Affiliation(s)
- H Link
- Department of Haematology and Oncology, Medizinische Hochschule, Hannover, Germany
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9
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Abstract
In patients, urinary levels of pentamidine have been shown to reflect pulmonary deposition of aerosolized drug. Using urinary levels and air filter samples, we assessed factors responsible for health care worker (HCW) exposure. We measured serial urine samples in HCWs who administered aerosol pentamidine over an 11-month period and compared them with serial urine levels measured over 30 days in a normal volunteer in whose lungs a known amount of pentamidine (3.39 mg) had been deposited. Ambient exposure to pentamidine was determined by continuous high volume air sampling in the treatment room during routine therapy. In addition, the amount of pentamidine released by six HIV-positive subjects, performing tidal breathing with a Respirgard II nebulizer in an airtight booth, was measured by extracting air from the booth through a filter. The effect of adding noseclips, of coughing (with nebulizer shut down), and of removing the nebulizer from the patient's mouth without turning it off, were determined. Pentamidine in the urine of the normal volunteer reached a peak concentration of 9.5 ng/mg creatinine/ml and was detectable for 30 days following the exposure. In HCWs, pentamidine was detected intermittently in four of five individuals with levels as high as 18.2 ng/mg creatinine/ml. Samples of ambient treatment room air indicated small daily releases of pentamidine (0.013 +/- 0.02 mg per patient treated), but simultaneous urine levels in HCWs were negative. The data from the airtight booth revealed that removing the nebulizer from a patient's mouth without turning it off caused a 360-fold increased in pentamidine release compared to tidal breathing. Coughing resulted in a 6.9 (range 0.9-14.2)-fold increase in release, while the addition of noseclips had no significant effect. The pattern of intermittently positive urine tests and the low levels of ambient pentamidine detected in the air of the treatment room suggest that HCWs are being exposed to episodic but high concentrations of pentamidine. High level exposure is most likely to occur during treatment interruptions which are usually precipitated by coughing episodes. Because of the intermittent pattern of exposure and slow clearance of pentamidine, urine assay is useful for detecting high intermittent exposure. Random air sampling is a sensitive indicator of low level exposures but may not detect episodic high level releases.
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Affiliation(s)
- T G O'Riordan
- Department of Medicine, State University of New York, Stony Brook 11794-8172
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10
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Abstract
To determine if urine pentamidine was reflective of lung pentamidine, we compared levels of the drug in bronchoalveolar lavage fluid and simultaneously obtained urine. Thirty-one patients who were receiving aerosolized pentamidine either as treatment or as prophylaxis underwent BAL and submitted urine samples for pentamidine analysis. Pentamidine was analyzed in both phases of BAL fluid (supernatant and cell pellet) and in urine using high performance liquid chromatography. Urine results were normalized for creatinine. Patients were categorized as prophylaxis failures (active Pneumocystis carinii pneumonia on prophylaxis), electives (free from PCP on prophylaxis), treatment (daily AP in treatment doses for active PCP, or miscellaneous (single dose of AP). Levels in BAL fluid and urine varied widely over several orders of magnitude. However, for all patients, we found a highly significant relationship between BAL supernatant and urine (r = 0.97, p less than 0.0001). No statistical differences were found when comparing levels of pentamidine between failures and electives; however, the number of failures was small. We conclude that urine pentamidine is related to lung pentamidine and can be used as a clinical indicator in patients receiving aerosolized therapy.
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Affiliation(s)
- G C Smaldone
- Department of Medicine, State University of New York, Stony Brook 11794-8172
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Smaldone GC, Vinciguerra C, Marchese J. Detection of inhaled pentamidine in health care workers. N Engl J Med 1991; 325:891-2. [PMID: 1875979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Berger BJ, Hall JE, Tidwell RR. High-performance liquid chromatographic method for the quantification of several diamidine compounds with potential chemotherapeutic value. J Chromatogr 1989; 494:191-200. [PMID: 2584316 DOI: 10.1016/s0378-4347(00)82668-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A high-performance liquid chromatographic method has been developed for the detection and quantification of pentamidine and pentamidine analogues of chemotherapeutic value in order to measure their concentration in physiological fluids. The compounds were extracted from urine over octadecyl solid-phase extraction columns, followed by chromatographic separation with an octadecyl reversed-phase column. For the mobile phase, a gradient of 31.5-37.5% acetonitrile in water, with sodium heptanesulfonate and tetramethylammonium chloride as ion modifiers, was used. This method was used to reliably detect levels as low as 341 ng/ml without concentration of the compounds during the solid-phase extraction. The assay was used to determine the effectiveness of several solid-phase extraction columns for isolating the compounds of interest and to quantify the amount of pentamidine and its analogues contained in the urine of dosed rats.
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Affiliation(s)
- B J Berger
- Department of Parasitology, School of Public Health, University of North Carolina, Chapel Hill 27599
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Conte JE, Upton RA, Phelps RT, Wofsy CB, Zurlinden E, Lin ET. Use of a specific and sensitive assay to determine pentamidine pharmacokinetics in patients with AIDS. J Infect Dis 1986; 154:923-9. [PMID: 3491164 DOI: 10.1093/infdis/154.6.923] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The first-dose pharmacokinetics of pentamidine were studied in patients with AIDS. Pentamidine isethionate (4 mg/kg) was administered intramuscularly or intravenously to two groups of six patients each. Serial plasma and urine concentrations were measured by high-performance liquid chromatography, which is accurate and precise (sensitivity limits, 2.29 ng/ml in plasma and 229 ng/ml in urine). The mean peak concentrations in plasma after intramuscular and intravenous administration were 209 ng/ml and 612 ng/ml, respectively. Plasma concentrations, which declined biexponentially, were detectable throughout the 24-hr dosing interval and fell to less than 25 ng/ml after 8 hr. The mean plasma clearance, elimination half-life, apparent volume of distribution, and apparent volume at steady state for intramuscularly treated patients were 305 liters/hr, 9.36 hr, 924 liters, and 2,724 liters, respectively; these parameters for intravenously treated patients were 248 liters/hr, 6.40 hr, 140 liters, and 821 liters, respectively. Renal clearance of pentamidine was 5.0% of the plasma clearance for intramuscularly treated patients and 2.5% for intravenously treated patients. We found significant differences in the pharmacokinetic parameters between intramuscularly and intravenously treated patients.
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