Our library of drug research abstracts drawn from the medical literature is updated on a regular schedule, and you can be assured that new triamterene research articles will be listed here shortly after becoming available to us.
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Medical research on triamterene
J Control Release. 2008 May 19;
Neubert A, Sternberg K, Nagel S, Harder C, Schmitz KP, Kroemer HK, Weitschies W
A novel in vitro dissolution test for drug-eluting stents (DES) based on the compendial flow-through cell was developed. The model contains an additional compartment simulating the vessel wall enabling the examination of drug release and distribution. The compartment consists of alginate hydrogel containing a central aperture forming the lumen for stent placement and media flow. The method was tested utilizing stents coated with hydrophilic (fluorescein sodium) and hydrophobic (triamterene) fluorescent model substances as well as the cytostatic drug doxorubicin hydrochloride and compared to standard dissolution methods. The results show the suitability of the developed method to observe drug release and distribution. The determination of model substance content in the compartments media, hydrogel and stent yielded differing distribution patterns for the model compounds and enabled the observation of redistribution processes. The dissolution profiles differed from the results of compendial dissolution testing. Besides lower endpoints and slower rises of media concentrations due to distribution into the hydrogel, the release rates from the stent coatings were altered. These findings emphasize the necessity to adapt dissolution testing for DES to the unique conditions influencing delivery to the vessel wall to learn more about local distribution and to anticipate the in vivo performance of DES.
Drug-induced crystal nephropathy: an update.
Expert Opin Drug Saf. 2008 Mar; 7(2): 147-58
Yarlagadda SG, Perazella MA
BACKGROUND: Several medications that are insoluble in human urine are known to precipitate within the renal tubules. Intratubular precipitation of either exogenously administered medications or endogenous crystals (induced by certain drugs) can promote chronic and acute kidney injury, termed crystal nephropathy. Clinical settings that enhance the risk of drug or endogenous crystal precipitation within the kidney tubules include true or effective intravascular volume depletion, underlying kidney disease, and certain metabolic disturbances that promote changes in urinary pH favoring crystal precipitation. OBJECTIVE: Identify and review previously described and recently recognized medications that cause crystal nephropathy. METHOD: A literature review was performed, using PubMed, Ovid, and Google Scholar, focusing on drugs (sulfadiazine, acyclovir, indinavir, triamterene, methotrexate (MTX), orlistat, oral sodium phosphate preparation, ciprofloxacin) that cause crystal nephropathy. RESULTS/CONCLUSION: Sulfadiazine, acyclovir, indinavir, triamterene, and MTX are known to cause crystal nephropathy. Recently, several medications, including orlistat, ciprofloxacin, and oral sodium phosphate solution, along with underlying risk factors have been described as causing crystal nephropathy.
Drug Metab Dispos. 2008 Jun; 36(6): 995-1002
Enokizono J, Kusuhara H, Ose A, Schinkel AH, Sugiyama Y
The role of breast cancer resistance protein (BCRP/ABCG2) in limiting the brain and testis penetration of xenobiotic compounds in the blood-brain and -testis barriers was investigated using Bcrp(-/-) mice. Tissue/plasma concentration ratios in the brain (K(p,brain)) and testis (K(p,testis)) obtained under steady-state conditions were significantly increased in Bcrp(-/-) mice for PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), N-hydroxyl PhIP, MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline), dantrolene, and prazosin. In addition, the K(p,brain) of triamterene and the K(p,testis) of 4'-hydroxyl PhIP were also significantly increased in Bcrp(-/-) mice. The effect of functional impairment of Bcrp on the brain uptake of PhIP, dantrolene, and daidzein in Bcrp(-/-) mice determined using in situ brain perfusion was weaker than that observed on the K(p) values. In vitro transcellular transport experiments using cell lines expressing mouse Bcrp or P-glycoprotein (Mdr1a/Abcb1a) showed that, among the tested Bcrp substrates, PhIP, MeIQx, prazosin, and triamterene are common substrates of Bcrp and P-glycoprotein. The K(p) values of common substrates exhibited a smaller increase both in the brain and testis of Bcrp(-/-) mice than expected from the in vitro Bcrp activities. The Bcrp-specific substrates were weak acids, whereas basic or neutral BCRP substrates were also P-glycoprotein substrates. These results suggest that BCRP limits the tissue penetration of xenobiotic compounds in the blood-brain and -testis barriers, but its in vivo importance is also modulated by P-glycoprotein activity.
Allergic interstitial nephritis possibly related to sunitinib use.
Am J Geriatr Pharmacother. 2007 Dec; 5(4): 341-4
Khurana A
BACKGROUND: Sunitinib is an oral multitargeted inhibitor indicated for the treatment of renal cell carcinoma. OBJECTIVE: This report describes a case of allergic interstitial nephritis possibly related to this agent. CASE SUMMARY: A 69-year-old female patient with a history of metastatic renal cell carcinoma after left radical nephrectomy presented to our nephrology clinic after completing 2 courses of sunitinib therapy. The patient was noted to have progressive kidney dysfunction with proteinuria, together with peripheral eosinophilia and eosinophiluria, which developed during the first of 2 cycles of sunitinib therapy. Her concomitant medications included atenolol, triamterene/hydrochlorothiazide, amlodipine, and multivitamin tablets, all of which she had been receiving at stable doses over the previous 2 years. There were no other over-the-counter medications involved and other possible causes of interstitial nephritis were excluded. The proteinuria, eosinophilia, and eosinophiluria worsened with the second course and resolved after sunitinib discontinuation, which resulted in initial stabilization followed by slight improvement in kidney function. The Naranjo Adverse Drug Reaction Probability Scale score for this event was 7, indicating a probable association of the event with the drug. With clinical improvement after discontinuation of sunitinib and the presence of a solitary remaining kidney and thrombocytopenia, renal biopsy was not performed after discussion with the patient. When challenged with a related agent, sorafenib, the patient experienced worsening of serum creatinine and increasing eosinophilia, similar to that noted with sunitinib, suggesting that this event may be a class effect. CONCLUSIONS: Nephrologists and oncologists should be aware of allergic interstitial nephritis as an adverse effect related to this agent. Although there are no current recommendations for monitoring serum creatinine with sunitinib therapy, we recommend that serum creatinine and white cell count with differential be checked within 2 weeks of initiation of therapy with sunitinib to enable earlier diagnosis of this condition and avoid renal damage.
Electrophoresis. 2007 Aug; 28(16): 2934-41
Tolba K, Belder D
Microchip electrophoresis (MCE) with native fluorescence detection has been applied for the fast quantitative analysis of pharmaceutical formulations. For this purpose, methods for fast separation and sensitive detection of the unlabeled diuretic drugs, amiloride, triamterene, bendroflumethiazide (BFMTZ), and bumetanide were developed. An epifluorescence setup was used enabling the coupling of different lasers into a commercial fluorescence microscope. The detection sensitivity of different excitation light sources was compared utilizing either a HeCd laser (lambda(exc) = 325 nm), a frequency quadrupled Nd:YAG laser (lambda(exc) = 266 nm), or a mercury lamp (lambda(exc) = 330-380 nm). At optimal conditions using the HeCd laser, the drugs were separated within 15 s with LODs less than 1 mug/mL for the four compounds. A linear relationship between concentration and peak area was obtained in the concentration range of 0.05-20 microg/mL with a mean correlation coefficient of around 0.996 for all analytes. The method was successfully applied to the analysis of the respective drugs in commercial formulations and in human urine without interference from other constituents. These data show that MCE has a great potential for reliable drug analysis.
Leg Med (Tokyo). 2007 Sep; 9(5): 258-64
Miller GM, Stripp R
In America, recent growth in the popularity of Chinese herbal/patent medicines (CHM/CPM) has generated concerns as to the safety of these and other herbal remedies. Lack of strict federal regulations has lead to the possibility of improper labeling and even adulteration of these products with western drugs or other chemical contaminants. Our laboratory has conducted an analytical study to determine the presence of undeclared pharmaceuticals and therapeutic substances within CHM/CPM sold in New York City's Chinatown. Ninety representative samples randomly purchased in the form of pills, tablets, creams and teas were screened by appropriate analytical techniques including TLC, GC/MS and HPLC. Five samples contained nine different western pharmaceuticals. Two of these samples contained undeclared or mislabeled substances. One sample contained two pharmaceuticals contraindicated in people for whom the product was intended. Drugs identified include promethazine, chlormethiazole, chlorpheniramine, diclofenac, chlordiazepoxide, hydrochlorothiazide, triamterene, diphenhydramine and sildenafil citrate (Viagra).
J Chromatogr B Analyt Technol Biomed Life Sci. 2007 Sep 1; 856(1-2): 381-5
Cheng CL, Fu CH, Chou CH
A capillary zone electrophoresis method has been developed for the direct determination of norfloxacin in the physiological perfusate of isolated rat liver. Norfloxacin and the internal standard triamterene were detected using laser-induced fluorescence (LIF) detection with the excitation and emission wavelength of 325 and 435 nm, respectively. The background electrolyte (BGE) was 50 mM phosphate buffer (pH 4.6). The effect of pH and concentration of BGE on the electrophoretic migration and fluorescence response of analytes were examined. Calibration curves were linear over a wide range of 0.01-100 microg/mL. The limit of quantitation was 0.01 microg/mL. The intra- and inter-day relative standard deviation was 3.7%, or less, and the accuracy was 93.2% of the nominal concentration. No endogenous substances were found to interfere. The method was used to characterize the steady-state and transient pharmacokinetics of norfloxacin in the rat liver.
Update of diuretics in the treatment of hypertension.
Am J Ther. 2007 Mar-Apr; 14(2): 154-60
Padilla MC, Armas-Hernández MJ, Hernández RH, Israili ZH, Valasco M
Diuretics, which are primarily used to modify the volume and the composition of body fluids, are widely used to treat hypertension. The diuretics include a) the thiazides and thiazide-like agents, which are the most common drugs used to treat high blood pressure (these drugs inhibit sodium reabsorption in the early distal convoluted tubule); b) loop diuretics, such as furosemide, block chloride and sodium reabsorption by inhibition of the Na/K/2Cl cotransport system in the thick ascending limb of the loop of Henle; and c) potassium-sparing (retaining) diuretics, including aldosterone receptor blockers (such as spironolactone and eplerenone) and epithelial sodium channel blockers (such as amiloride and triamterene, which interfere with the reabsorption of sodium and excretion of potassium and hydrogen that takes place in the late distal tubule, the connecting tubule, and the cortical collecting duct). Hydrochlorothiazide 12.5 mg once daily or equivalent low dosages of other similar agents reduce blood pressure in approximately one-half to two-thirds of patients who are responsive to this class of drugs; higher doses add little to the effect on blood pressure and also increase side effects. Some combinations of very small doses of thiazide diuretics - for example, 6.25 mg hydrochlorothiazide or 0.625 mg indapamide, with a low dose of an antihypertensive drug of a different class - have average antihypertensive efficacy when used once daily. Furosemide is used in patients with renal failure or severe heart failure and is best given by continuous intravenous infusion. The potassium-sparing diuretics are generally used in combination with thiazide diuretics to treat hypertension. Side effects occur at about the same frequency and severity with equipotent doses of all diuretics. The incidence of side effects is dose-dependent and also increases as a function of the duration of the renal excretory and antihypertensive actions. However, longer-acting diuretics provide better 24-hour control of blood pressure and increase compliance and adherence to the treatment regimen.
J Org Chem. 2007 Apr 13; 72(8): 2857-64
Pelly SC, Govender S, Fernandes MA, Schmalz HG, de Koning CB
The first enantioselective synthesis of the 2-isopropenyl-2,3-dihydrobenzofuran skeleton of tremetone and hydroxytremetone from (E)-4-(2-hydroxyphenyl)-2-methyl-2-butenyl methyl carbonate and (E)-4-(2,6-dihydroxyphenyl)-2-methyl-2-butenyl methyl carbonate, respectively, is described. The key step is a catalytic palladium-mediated reaction in the presence of the chiral Trost ligand.
J Sep Sci. 2006 Dec; 29(18): 2765-71
Brunelli C, Bicchi C, Di Stilo A, Salomone A, Vincenti M
In official doping controls, about 300 drugs and metabolites have to be screened for each sample. Moreover, the number of determinations to be routinely processed increases continuously as the number of both samples and potential illicit drugs keeps growing. As a consequence, increasingly specific, sensitive, and, above all, fast methods for doping controls are needed. The present study presents an efficient fast-GC/MS approach to the routine screening of two different classes of doping agents, namely beta-adrenoceptor ligands and diuretics (belonging to the S3, P2, and S5 groups of the WADA list of prohibited substances). Narrow bore columns (100 mm id) of different lengths and coated with apolar stationary phases were successfully used to separate the derivatized analytes; preliminary experiments (results not shown) showed better performances with OV-1701 for the separation of beta-adrenoceptor ligands. On the same stationary phase some diuretics required too high a temperature or a long isothermal time for elution, in which case a DB1-MS column was preferred. Two methods of sample preparation, derivatization, and analysis were used on aqueous standard mixtures of, respectively, (i) eight beta-adrenoceptor ligands, including five beta-antagonists (acebutolol, alprenolol, atenolol, metoprolol, pindolol) and three beta2-agonists (salbutamol, clenbuterol, terbutaline) and (ii) seventeen diuretic drugs (acetazolamide, althiazide, bendroflumethiazide, bumethanide, canrenone, chlorothiazide, chlortalidone, clopamide, ethacrinic acid, furosemide, hydrochlorothiazide, hydroflumethiazide, indapamide, indomethacine, spironolactone, triamterene, trichloromethiazide) and one masking agent (probenecid). The mixture of beta-adrenoceptor ligand derivatives was efficiently separated in about 5.6 min, while the one of 18 diuretics and masking agents required less than 5 min for analysis. Limits of detection were from 1 microg/L for pindolol, ethacrinic acid, furosemide, indomethacine, and trichloromethiazide, to 20 microg/L for terbutaline, salbutamol, and metoprolol, and 50 microg/L for clopamide; the instrumental repeatability proved to be excellent (area RSD%