A novel HPLC assay for pentamidine: comparative effects of creatinine and inulin on GFR estimation and pentamidine renal excretion in the isolated perfused rat kidney.

PURPOSE 1. To develop and validate an analytical method for pentamidine (PTM) by reversed-phase HPLC. 2. To compare the effects of creatinine and inulin on PTM excretion in the isolated perfused rat kidney. METHODS The HPLC method utilized a base deactivated, 5 micro, C18 column and a mobile phase containing acetonitrile (24%) and 0.025 M monobasic phosphate buffer, pH 3.2 (76%). Mobile phase flow rate and UV detection wavelength were 1 mL/min and 270 nm, respectively. Sulfadiazine (SDZ) was used as the internal standard. The method was used to measure pentamidine in perfusate and urine samples generated from studies with the isolated perfused rat kidney (IPK) model. Perfusion experiments were conducted in the presence of two different GFR markers: creatinine and inulin (PTM dose 800 micro g). Both creatinine and inulin were assayed using colorimetric methods. RESULTS The HPLC assay is rapid, sensitive and reproducible. The method was validated over two standard concentration ranges: 0.1 to 1 micro g/mL, and 1 to 10 micro g/mL. In control (drug-naïve) IPK perfusions, creatinine clearance was approximately 15% greater than inulin clearance (0.80+/- 0.21 mL/min vs. 0.69+/-0.17 mL/min, p > 0.05). In the presence of PTM, however, creatinine clearance was reduced to 0.56+/-0.27 (p < 0.05 compared to control). Inulin clearance was not altered by PTM administration (0.76+/-0.26 mL/min). Cumulative urinary excretion of PTM (% dose) was 3.0+/-0.47% and 9.6+/-4.2% in the presence of creatinine and inulin, respectively. PTM clearance was significantly reduced (0.06+/-0.01 mL/min vs. 0.13+/-0.01 mL/min, p < 0.05) and % kidney accumulation significantly enhanced (66+/-4.7% vs. 37+/-9.7%, p < 0.05) by creatinine. CONCLUSIONS Creatinine overestimated GFR in the IPK. The altered renal excretion of PTM by creatinine is consistent with inhibition of PTM tubular secretion. Because of increased kidney accumulation, detrimental effects of PTM on renal function were observed. Based on these findings, creatinine should be used cautiously as an indicator of GFR in IPK experimentation.

[1]  G. Gabriëls,et al.  Potassium-Sparing Renal Effects of Trimethoprim and Structural Analogues , 2000, Nephron.

[2]  K. Sweeney,et al.  Concentration-dependent tubular secretion of acetazolamide and its inhibition by salicylic acid in the isolated perfused rat kidney. , 1996, Drug metabolism and disposition: the biological fate of chemicals.

[3]  R. Toto,et al.  Conventional measurement of renal function utilizing serum creatinine, creatinine clearance, inulin and para-aminohippuric acid clearance. , 1995, Current opinion in nephrology and hypertension.

[4]  K. Sweeney,et al.  The influence of protein binding on the elimination of acetazolamide by the isolated perfused rat kidney: evidence of albumin-mediated tubular secretion. , 1995, The Journal of pharmacology and experimental therapeutics.

[5]  T. Kleyman,et al.  A Mechanism for Pentamidine-Induced Hyperkalemia: Inhibition of Distal Nephron Sodium Transport , 1995, Annals of Internal Medicine.

[6]  R. Balaña-Fouce,et al.  Determination of Pentamidine in Leishmania Infantum Promastigotes by Ion-Paired Liquid Chromatography , 1994 .

[7]  P. Statkevich,et al.  Characterization of methotrexate elimination and interaction with indomethacin and flurbiprofen in the isolated perfused rat kidney. , 1993, Journal of Pharmacology and Experimental Therapeutics.

[8]  A. Gervais,et al.  Clinical usefulness of high-pressure liquid chromatographic determination of serum pentamidine in AIDS patients. , 1992, Clinical biochemistry.

[9]  B. Berger,et al.  Problems and Pitfalls in the Assay of Pentamidine , 1992, Clinical pharmacokinetics.

[10]  G. Bailie,et al.  Pentamidine-Associated Nephrotoxicity and Hyperkalemia in Patients with Aids , 1991, DICP : the annals of pharmacotherapy.

[11]  J. Hall,et al.  Activity of pentamidine and pentamidine analogs against Toxoplasma gondii in cell cultures , 1991, Antimicrobial Agents and Chemotherapy.

[12]  J. Hall,et al.  Inhibition of Cryptosporidium parvum in neonatal Hsd:(ICR)BR Swiss miceby polyether ionophores and aromatic amidines , 1991, Antimicrobial Agents and Chemotherapy.

[13]  J. Hall,et al.  Structure-activity relationships of pentamidine analogs against Giardia lamblia and correlation of antigiardial activity with DNA-binding affinity , 1991, Antimicrobial Agents and Chemotherapy.

[14]  Ö. Ericsson,et al.  Determination of Pentamidine in Whole Blood, Plasma, and Urine by High‐Performance Liquid Chromatography , 1990, Therapeutic drug monitoring.

[15]  R. Wong,et al.  Focus on aerosolized pentamidine: an agent for prophylaxis of Pneumocystis carinii pneumonia. , 1990 .

[16]  K. Ilett,et al.  High‐Performance Liquid Chromatographic Method for Measurement of Pentamidine in Plasma and Its Application in an Immunosuppressed Patient with Renal Dysfunction , 1987, Therapeutic drug monitoring.

[17]  C. Wofsy,et al.  Use of a specific and sensitive assay to determine pentamidine pharmacokinetics in patients with AIDS. , 1986, The Journal of infectious diseases.

[18]  T. Maack.  Renal clearance and isolated kidney perfusion techniques. , 1986, Kidney international.

[19]  Jasmine Lin,et al.  High Performance Liquid Chromatographic Determination of Pentamidine in Plasma , 1986 .

[20]  T. Navin,et al.  High-performance liquid chromatographic method for quantitation of pentamidine in blood serum. , 1985, Journal of chromatography.

[21]  A. Bryceson,et al.  Visceral leishmaniasis unresponsive to antimonial drugs. II. Response to high dosage sodium stibogluconate or prolonged treatment with pentamidine. , 1985, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[22]  W. Colburn,et al.  Influence of protein binding and metabolic interconversion on the disposition of sulfisoxazole and its N4-acetyl metabolite by the isolated perfused rat kidney. , 1984, Drug metabolism and disposition: the biological fate of chemicals.

[23]  G. Tucker,et al.  Measurement of the renal clearance of drugs. , 1981, British journal of clinical pharmacology.

[24]  W A Colburn,et al.  Renal clearance of carprofen in the isolated perfused rat kidney. , 1981, Drug metabolism and disposition: the biological fate of chemicals.

[25]  W. Colburn,et al.  Pharmacokinetics of saccharin in the rat. Renal clearance in vivo and in the isolated perfused kidney. , 1980, Drug metabolism and disposition: the biological fate of chemicals.

[26]  F. I. Apted.  Present status of chemotherapy and chemopropylaxis of human trypanosomiasis in the Eastern Hemisphere. , 1980, Pharmacology & therapeutics.

[27]  P. Flecknell,et al.  Experimental and surgical technique in the rat. , 1980 .

[28]  R. H. Bowman.  Methodology for Study of Isolated Perfused Rat Kidney in Vitro , 1978 .

[29]  M. H. Gault,et al.  Assay of inulin in tissues using anthrone , 1975 .

[30]  R. H. Bowman.  [1] The perfused rat kidney , 1975 .

[31]  R. H. Bowman.  The perfused rat kidney. , 1975, Methods in Enzymology.

[32]  H. Krebs,et al.  Metabolic activities of the isolated perfused rat kidney. , 1967, The Biochemical journal.

[33]  M. Sass,et al.  The use of capillary blood for estimating renal clearance of inulin and glucose excretion by means of an anthrone procedure. , 1956, The Journal of laboratory and clinical medicine.

[34]  J. Prudden,et al.  Simultaneous determination of sucrose and inulin in biologic fluids. , 1954, The Journal of laboratory and clinical medicine.