Gas chromatographic and high-performance liquid chromatographic methods for the determination of genaconazole in biological fluids

Gas chromatographic (GC) and high-performance liquid chromatographic (HPLC) methods were developed for the determination of genaconazole in biological fluids. Both methods involved organic solvent extraction followed by solid-phase extraction on a C18 column. GC analysis utilized a megabore column (DB-17) with 63Ni electron-capture detection, whereas HPLC analysis utilized separation on a reversed-phase column with a methanol-phosphate buffer mixture as the mobile phase and quantitation by UV absorbance at 208 nm. Both methods yielded good linearity, accuracy and precision. The limit of quantitation (LOQ) was 0.025 microgram per ml of serum for GC and 0.2 microgram per ml of serum or 0.5 microgram per ml of urine for HPLC analysis. Both GC and HPLC methods were used for the determination of serum concentration-time curves of genaconazole in man following oral administration of a 50-mg dose.

Determination of SCH 39304 by megabore capillary gas-liquid chromatography

A gas-liquid chromatographic procedure for determination of SCH 39304 at low nanogram concentrations in serum, cerebrospinal fluid, and urine is presented. The methodology combines a high selectivity and sensitivity nitrogen-specific detector, a gas chromatograph equipped with a capillary "megabore" column, and an internal standard that is very similar in chemical structure to the drug being assayed. This method is suitable for both pharmacokinetic studies as well as for monitoring drug levels in patients receiving SCH 39304 for antifungal treatment.

Disposition of a new antiinfective agent 1,3-di(4-imidazolino-2-methoxyphenoxy)propane in male rats

The disposition of 1,3-di[4-imidazolino-2-methoxyphenoxy]propane (DMP) is described in male rats following a single 2.5 mg/kg intravenous or 10 mg/kg oral administration of DMP lactate in an aqueous (5% dextrose) solution. Following the intravenous administration, plasma concentrations of DMP declined in an apparent biexponential manner and were nonmeasurable after 24 hr. The mean terminal plasma elimination half-life was 14.9 hr. A volume of distribution of 18.7 liters/kg and a body clearance of 14.5 ml/min/kg were estimated. After oral administration, mean plasma concentrations of DMP reached a maximum of 39.6 ng/ml at 15 min and were nonmeasurable after 4 hr. The areas under the curve (AUC)0-24 of DMP was 2276 ng.hr/ml following the intravenous dose. The AUC0-4 was 68 ng.hr/ml following the oral dose. The AUC0-4 was 68 ng.hr/ml following the oral dose. Based on a comparison of AUC0-4, the oral bioavailability was 0.9%. A mean of 41.7 and 0.4% of the dose was excreted in urine as DMP following intravenous and oral administration, respectively. The tissue distribution and mass balance of total 14C were determined following a single 2.5 mg/kg intravenous administration of [14C]DMP.lactate. The concentrations of total 14C in all tissues were highest at 0.5 hr and declined with time thereafter. The highest concentration of 14C was in the kidneys, whereas the highest total amount was in the liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of cutaneous Sulconazole nitrate in the hairless rat: absorption, excretion, tissue concentrations

After cutaneous application of radioactive solutions of Sulconazole nitrate in the hairless rat, the total absorption of the substance by the skin, estimated from the sum of the cumulative urinary and fecal excretions over 96 h, was 2.4% of the dose administered. The elimination reached a maximum between 6 and 24 h and was virtually complete after 96 h. The excretion was almost equally distributed between the urine and the feces, which corresponds to an intense elimination via the biliary tract. The quantities present in the stratum corneum, epidermis and dermis at the end of the period of contact constituted another estimation of the total absorption of the substance which confirmed the previous estimation (3.6% of the dose). The measurement of the concentrations of Sulconazole and its metabolites in the various layers of the skin revealed a high affinity of the substance for the stratum corneum, where it remained present in large quantities for more than 48 h. This affinity is due to the very intense lipophilia of the molecule. The concentrations in the other tissues were inversely proportional to the distance from the surface of the skin and were virtually nil in the circulating blood. These results suggest the absence of risk of systemic effects after cutaneous administration of Sulconazole and support the recommended therapeutic protocol in man (one administration per day).

Pharmacokinetic study of [14C]flutrimazole after oral and intravenous administration in dogs. Comparison with clotrimazole

This trial involved a comparative study using 6 Beagle dogs on the pharmacokinetics of 14C-labelled 1-[(2-fluorophenyl)(4-fluorophenyl)phenylmethyl]-1H-imidazole (flutrimazole, CAS 119006-77-8) and [14C]clotrimazole labelled in the imidazole ring. On the basis of a cross-over trial, each animal received a dose of 5 mg/kg (approx. 100 microCi) [14C]flutrimazole and [14C]clotrimazole, both intravenously and orally. The levels in plasma, urine and faeces of the total radioactivity, unchanged drug and the [14C]imidazole formed by metabolization of the unchanged drug were determined. Flutrimazole presented a biological half-life (t1/2) of 14.4 +/- 3.8 h and a clearance (Cl) of 6.7 +/- 0.8 l/h, while the values for clotrimazole were very different: t1/2 4.6 +/- 0.8 h and Cl: 13.6 +/- 1.0 l/h. After oral administration a fraction of absorbed dose (f) of 78 +/- 21% and bioavailability of 8.9 +/- 6.1% were calculated for flutrimazole. For clotrimazole, these were: 52 +/- 10% and 4.9 +/- 1.9%, respectively. Both drugs showed a significant first-pass effect, with 90% of the absorbed dose being metabolized before reaching the systemic circulation. The total recovery of radioactivity in faeces and urine 5 days after i.v. and oral administration was 58% and 68%, respectively, for [14C]flutrimazole, and 81% and 79% for [14C]clotrimazole. In both cases, most of the radioactivity was recovered in the faeces. The high radioactivity obtained in faeces after i.v. administration of both drugs confirms biliary elimination. For both flutrimazole and clotrimazole, less than 1% of the total recovered in the urine after i.v. administration was recovered as unchanged drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of L-671,329 in rhesus monkeys and DBA/2 mice

The time course of plasma drug levels and urinary recovery for two lipopeptide antifungal antibiotics, L-671,329 and cilofungin, were measured in male rhesus monkeys (Macaca mulatta) and in female DBA/2 mice. The antibiotics were administered intravenously at 10 mg/kg of body weight in phosphate-buffered saline-26% polyethylene glycol for the rhesus monkeys and in 5% dimethyl sulfoxide for the mice. Plasma and urine drug concentrations were determined by high-pressure liquid chromatography and/or a microbiological assay versus Aspergillus niger, and pharmacokinetic parameters were determined for both species. In each of the two rhesus crossover tests as well as in the mouse studies, the pharmacokinetics of the two compounds were similar; however, a marked difference was evident between species. The half-lives of L-671,329 and cilofungin in plasma were 39 and 34 min in the mice and averaged 1.8 and 2 h in the rhesus monkeys, respectively. In mice and rhesus monkeys, urinary recovery was less than 4% for both compounds.

Systemic absorption of 3H-fenticonazole after vaginal administration of 1 gram in patients

Fourteen women, five with normal cervicovaginal mucosa (Group 1), five with cervical carcinoma (Group 2) and four with relapsing vulvovaginal candidiasis (Group 3) were enrolled and completed this open clinical trial. Each subject received a single dose of 1.82 +/- 0.3 g on average of vaginal paste (for ovules) containing about 1000 mg of 3H-fenticonazole nitrate (266 microCi). Twelve hours after vaginal administration, the paste was removed by vaginal washing. Blood, urine and stool samples were collected at specified time intervals for five days. Plasma, urine, stools and all used material in contact with the paste were assayed for radioactivity. No measurable levels of radioactivity were detected in plasma of subjects of Groups 1 and 3 while in 4 of the 5 subjects with cervical carcinoma (Group 2) fenticonazole was detected during the 24 h after administration with a peak level at about 8 hours. For a period of 5 days, 0.4-1.5% of the dose on average was recovered from urine, and 0.18-0.32% from feces. Based on the excretion data, the extent of vaginal absorption of fenticonazole nitrate in women with vulvovaginal candidiasis was 1.81 +/- 0.57% of the dose, while in women with normal cervicovaginal mucosa it accounted for 0.58 +/- 0.28% of the administered dose. In patients with cervical carcinoma, absorption was 1.12 +/- 0.53%. The maximum amount absorbed corresponds to an exposure of about 0.4 mg/kg of fenticonazole nitrate (for a subject weighing 50 kg). Consequently, the vaginal administration of one ovule containing 1000 mg of fenticonazole nitrate seems to be devoid of risk for patients.

High-performance liquid chromatographic method for the quantification of several diamidine compounds with potential chemotherapeutic value

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.

Analytical methods for the determination of terbinafine and its metabolites in human plasma, milk and urine

Analytical procedures have been developed for the determination of the allylamine antimycotic terbinafine (1) and its demethylderivate (2) in plasma, milk and urine, and the metabolite carboxy-terbinafine (3) in plasma and urine, as well as the further metabolites demethyl-carboxy-terbinafine (4) and naphthoic acid (5) in urine. HPLC-methods for plasma analysis employed either electrochemical detection (for 1 and 2) or UV-detection (for 3) following a protein precipitation step with methanol or sample extraction with hexane as appropriate. For quantitative urine analysis of substances 1-4 native urine samples were deconjugated, mixed with internal standard and injected by an autosampler into a microprocessor controlled HPLC-system. The substances were monitored by UV-absorption. The metabolite 5 was determined in urine after deconjugation, sample preparation with commercially available cartridges and silylation by automatized GC with fused silica capillary column and FID-detection. The standard calibration curves for the parent compound (1) and metabolites (2-5) are linear within the required analytical ranges. The detection limit for 1 and 2 is 50 ng/ml in plasma and 150 ng/ml in milk and for 3 in plasma 100 ng/ml. The detection limit in urine is 300 ng/ml for all substances (1-4) analyzed by HPLC and 50 ng/ml for 5 analyzed by GC.

Pharmacokinetics of two spiroarsoranes administered intravenously or orally to rabbits

The pharmacokinetics of two spiroarsorane molecules (1,2) were investigated after both intravenous bolus and an oral administration in rabbits. After iv administration of a 15-mg/kg dose, for the two substances, the plasma concentration-time curves were well described by an open two-compartmental model. The half-lives of the first phase were 0.47 +/- 0.12 and 0.27 +/- 0.02 h for 1 and 2, respectively. The half-lives of the terminal phase were of the same order of magnitude for the two substances: 4.38 +/- 0.24 and 6.03 +/- 1.14 h, respectively. Total plasma clearances were 2.47 +/- 0.44 and 0.81 +/- 0.04 L/h, respectively, and the steady-state volume of distribution of 2 (14.99 +/- 2.57 L) was larger than that of 1 (4.27 +/- 0.28 L). After oral administration, spiroarsorane 2 was not absorbed. The availability of the suspension of 1 was 18%. The rate of the absorption phase of 1 showed a saturation process, probably due to the solubility of the molecule. When increasing oral doses of 1 (15, 30, and 60 mg/kg) were administered, the plasma concentrations did not increase to the same extent.

Percutaneous absorption of sulconazole nitrate in humans

The percutaneous absorption of 1% sulconazole nitrate in a cream formulation containing 3H-labeled drug has been studied in seven human subjects. Two applications of 4.5 g each were made to 450 cm2 of abdominal skin at 0 and 12 h, and the site was washed at 24 h. The application site was subsequently washed at 24-h intervals for 3 consecutive days, and 6.7% of the dose was recovered in the urine and 2.0% in the feces following a 7-d collection period. Radioactivity was detectable in the plasma from 8-96 h, with a peak occurring at 24 h, and could also be recovered in the skin wash up to 96 h after application. Total percutaneous absorption of sulconazole was estimated to be 8.7-11.3% of the applied dose, considerably more than that previously reported for other imidazole drugs.

Determination of fluconazole in biological fluids by capillary column gas chromatography with a nitrogen detector

Fluconazole concentrations in biological fluids were determined by high-performance gas chromatography. A simple extraction procedure with chloroform, under basic conditions and after the addition of UK-47,265 as the internal standard and with no evaporation stage, was carried out prior to analysis. A solid injector and a 15-m capillary column, coated with a nonpolar phase and connected to a nitrogen-selective detector that afforded an excellent selectivity and sensitivity, constituted the gas chromatographic system. The duration of each analysis was less than 4 min and the minimum detectable serum concentration was 50 ng/mL. In five patients undergoing chronic peritoneal dialysis, the mean serum concentrations +/- SD at 1, 6, and 48 h after the intraperitoneal administration of a single dose of fluconazole were, respectively, 325 +/- 75, 928 +/- 159, and 607 +/- 80 ng/mL.

High-pressure liquid chromatographic method for determination of Sch 28191 in biological fluids

A high-pressure liquid chromatographic method has been developed for the measurement of N-D-ornithyl amphotericin B methyl ester (Sch 28191) in biological fluid. The method involves protein precipitation with methanol, followed by separation of the supernatant on a reverse-phase column and quantitation by absorbance at 405 nm. This technique resulted in a recovery of 97%. There was a good linear relationship between the peak height ratio and Sch 28191 concentrations ranging from 0.015 to 20 micrograms/ml. In addition, this method was specific for Sch 28191 since all of its analogs tested did not interfere with the assay. The method was reproducible with a lower limit of quantitation of 0.015 microgram/ml. Serum levels obtained from this method were in good agreement with those obtained from a microbiological assay only when drug concentrations were higher than 1.5 microgram/ml. The high-pressure liquid chromatographic method is useful in monitoring serum and urine drug levels in animals and should prove to be useful for pharmacokinetic studies of the drug with therapeutic doses in humans.

Antifungal activity in human urine and serum after ingestion of garlic (Allium sativum)

A fresh extract of garlic (Allium sativum) was administered orally to human volunteers. At intervals, serum and urine were collected and assayed for antifungal activity. The maximum tolerable dose was determined to be 25 ml of garlic extract. Larger amounts caused severe burning sensations in the esophagus and the stomach and vomiting. After oral ingestion of 25 ml of the extract, anticandidal and anticryptococcal activities were detected in undiluted serum 0.5 and 1 h after ingestion. No detectable antifungal activity was found in the excreted urine at any time after oral ingestion. Oral garlic is of limited value in the therapy of human fungal infections.

Laboratory assessment of the antimycotic drug clotrimazole

Laboratory studies on clotrimazole showed that it had marked activity in vitro against all the Candida spp. and Cryptococcus spp. tested, against almost all strains of dermatophytes, and against Aspergillus spp and other fungal genera responsible for systemic mycoses; it had limited activity towards Gram-positive bacteria. The majority of Candida strains required MICs below 1 mug/ml and MCCs below 2 mug/ml.Serum, urine, and faecal assays of clotrimazole were made by microbiological methods on five children who received 100 mg/kg/day clotrimazole for several weeks. In-vitro sensitivity tests and biological fluid drug assays are also reported on specimens from 18 patients in other hospitals receiving clotrimazole for severe candidosis; several were renal transplant cases. Similar investigations are reported on specimens from 18 patients with pulmonary aspergilloses. The significance of low levels of the drug in body fluids, even after prolonged therapy, is discussed, and it is suggested that clotrimazole may be the first of a long series of imidazole derivatives with varying pharmacological and therapeutic properties.

Systemic antifungal activity of pyrrolnitrin

The antifungal activity of pyrrolnitrin, previously shown to be effective against superficial infections, was evaluated against experimental systemic mycoses. Pyrrolnitrin was inhibitory in vitro at <0.78 to 100 mug/ml to Candida albicans, Cryptococcus neoformans, Blastomyces dermatitidis, Sporotrichum schenckii, and Histoplasma capsulatum. Pyrrolnitrin activity was reduced about 90% in sera. After multiple subcutaneous doses of pyrrolnitrin at 20 mg/kg, activity was recovered in mouse blood and urine as well as kidney, liver, and brain homogenates. Multiple daily doses (50 mg/kg) of this antibiotic were effective in reducing by 74% the number of viable cells of C. albicans recovered from kidney homogenates. Multiple doses (15 mg/kg) resulted in a 74% reduction in the number of C. neoformans from brain homogenates. Pyrrolnitrin was ineffective in reducing the recovery of B. dermatitidis or H. capsulatum from liver or spleen homogenates of infected mice. When compared with amphotericin B, hamycin, 5-fluorocytosine, and saramycetin, this antibiotic was less effective. This study indicates that pyrrolnitrin would have limited usefulness as a systemic antifungal agent.