Concentrations of tinidazole in gingival crevicular fluid and plasma in dogs after multiple dose administration

Tinidazole 15 mg/kg was administered to eight Beagle dogs with gingivitis or periodontitis twice daily for 3 days. Tinidazole concentrations in blood and gingival crevicular fluid (GCF) were measured 1, 3, 6 and 9 h after the morning dose each day. The concentration of tinidazole was determined by high performance liquid chromatography (HPLC). The mean concentration of tinidazole in GCF for each dog ranged from 6.05 to 9.32 micrograms/mL at different time points after the first dose, and on the first day the highest concentration was observed 6 h after the drug administration. Tinidazole concentrations were 34 +/- 4%-72 +/- 9% (mean +/- SEM) of simultaneous plasma concentration. At steady-state, on the third treatment day, the mean tinidazole concentrations in GCF ranged from 6.68 to 13.1 micrograms/mL, i.e. 44 +/- 6%-75 +/- 25% of the corresponding concentrations in plasma. Tinidazole concentration in GCF exceeded the MIC values for putative path-ogenic periodontal bacteria and it is concluded that, when indicated, tinidazole could be used for chemotherapy of periodontitis in dogs.

Rapid and selective high-performance liquid chromatographic method for the determination of metronidazole and its active metabolite in human plasma, saliva and gastric juice

A rapid and selective HPLC method has been developed for the separation and quantitation of metronidazole and its hydroxylated metabolite in human plasma, saliva and gastric juice. The assay requires a simple protein precipitation step prior to analysis and is selective, sensitive and reproducible. The limits of quantitation (0.5-ml sample) were at least 0.25 microgram/ml for metronidazole and 0.20 micrograms/ml for its hydroxy metabolite. A Hypersil ODS 5 micron (150 x 4.5 mm I.D.) column was used with a mobile phase of acetonitrile-aqueous 0.05 M potassium phosphate buffer (pH 7) containing 0.1 % triethylamine (10:90) delivered at a flow-rate of 1.0 ml/min.

Bacterial mutagens in the urine of patients under tinidazole treatment

Tinidazole is an antiparasitic drug belonging to the 5-nitroimidazole family. It is prescribed against protozoal infestations and is widely used in Mexico as well as other underdeveloped countries where infectious diseases are the first cause of children mortality. The drug is a direct mutagen in Salmonella typhimurium TA100 strain and the presence of S9 mixture did not modify its mutagenic effect. At low doses no mutagenicity was detected with strains TA100NR, TA98 or UTH8414 (Uvr+ derivative of TA100). Urine from four patients under tinidazole treatment exhibited a mutagenic activity on strain TA100, greater than the expected from the tinidazole concentrations determined by high-performance liquid chromatography (HPLC). Components from the urine samples were separated on thin-layer chromatography (TLC) plates, and their mutagenic effects tested by direct application of the Salmonella assay onto sections of the developed chromatoplate. The Rf of one component (0.62) corresponded to the one obtained for a tinidazole standard and showed the expected mutagenicity, while a second component with an Rf=0.39, exhibited a mutagenic potency slightly greater than the observed for tinidazole; however, as in the case of the drug itself, reduction of the nitro group was necessary for a mutagenic activity.

Effect of enzyme induction and inhibition on the fate of metronidazole and tinidazole in the rat

The excretion routes of intact metronidazole and tinidazole were studied in rats kept in metabolism cages and cannulated for continuous bile collection. The nitroimidazoles were given intraarterially either alone or after a 5-day pretreatment with phenobarbitone (70 mg/kg/day intravenously) or after a single dose of cimetidine (50 mg/kg intraarterially). After 30 mg/kg, 27.0% of the metronidazole dose was excreted intact in 24-hr urine and 2.2% in bile. After tinidazole, the recoveries of the intact drug in urine and bile were 48.1% and 1.7%, respectively. After 90 mg/kg, the total recoveries of both drugs were 25-28% smaller than after 30 mg/kg. Phenobarbitone pretreatment did not affect metronidazole levels in plasma but decreased tinidazole levels at 4 hrs. The 24-hr recoveries of the intact nitroimidazoles in urine were significantly reduced by phenobarbitone while the 24-hr bile recoveries were not. Cimetidine treatment enhanced both metronidazole (at 1, 2 and 3 hrs) and tinidazole (only at 1 hr) concentrations in plasma, but this shift was not reflected in the 24-hr urine recoveries of the intact nitroimidazoles. Cimetidine doubled, however, the 24-hr bile recovery of the intact tinidazole. The calculations of the apparent degree of metabolism, assuming no methodological losses, showed that phenobarbitone increased the metabolism of tinidazole by about 62% and that of metronidazole only by about 16%. The effect of a single dose of cimetidine was negligible.

Pharmacokinetics and metabolism of 14C-tinidazole in humans

Following intravenous infusion of 800 mg of 14C-tinidazole during 30 min to two human subjects, a mean of 44% of the dose was excreted in urine during the first 24 h, increasing to 63% of the dose during five days: 12% of the dose was excreted in the faeces, indicating the possible involvement of biliary excretion and other secretory processes in the disposition of tinidazole. At 6 min after the end of the infusion, the mean plasma tinidazole concentration was 12 mg/l. Tinidazole was a major component in 0-120 h urine (about 32% of urinary 14C): the major metabolite in the 0-12 h urine examined was ethyl 2-(5-hydroxy-2-methyl-4-nitro-1-imidazolyl)ethyl sulphone (about 30% urinary 14C), the product of hydroxylation and nitro-group migration. These compounds were also present in the faeces. A minor urinary metabolite was 2-hydroxymethyltinidazole (about 9% urinary 14C), which was also present in plasma. The mean pharmacokinetic parameters obtained for tinidazole were similar to those reported in the literature; total clearance 51 ml/min, renal clearance 10 ml/min, volume of distribution 501 and half-life 11.6 h.

Concentrations of metronidazole and tinidazole in male genital tissues

The steady-state concentrations of metronidazole and tinidazole in male genital tissues were analyzed in patients subjected to elective gonadal surgery. The nitroimidazoles were administered orally at 500 mg every 8 h, beginning 5 days before the operation. Eight hours after the last dose, the concentrations of tinidazole were 24.1 +/- 2.5 micrograms (mean +/- standard error of the mean)/g of prostatic tissue, 29.1 +/- 2.9 micrograms/g of vas deferens, 22.1 +/- 2.1 micrograms/g of epididymis, and 18.6 +/- 2.3 micrograms/g of testis. The corresponding values of metronidazole were 14.3 +/- 1.8 micrograms/g, 15.9 +/- 1.2 micrograms/g, 14.0 +/- 1.2 micrograms/g, and 12.5 +/- 1.7 micrograms/g, respectively.

Comparative pharmacokinetics of metronidazole and tinidazole and their tissue penetration

Since metronidazole and tinidazole are used prophylactically against infections after colorectal surgery, their pharmacokinetics and that of hydroxy-metronidazole were compared in 34 such patients. Seventeen patients received a single dose of 1.5 g (50-min infusion) of either agent 1 h before the operation. The concentrations of serum and tissue homogenates (subcutaneous fat, omentum, peritoneum, ileum, appendix, colon) were assayed by high-pressure liquid chromatography. The serum concentrations 1 h after start of infusion were 34.1 +/- 6.7 mg/l of metronidazole, 2.3 +/- 1.2 mg/l of OH-metronidazole, and 35.2 +/- 6.3 mg/l of tinidazole. OH-metronidazole and tinidazole were detectable for 72 h and metronidazole for 48 h. The ranges of serum and tissue concentrations (subcutaneous fat, omentum, peritoneum, ileum, appendix, colon) overlapped (within one single standard deviation). The tissue concentrations were high, particularly in intestinal tissues, except that the levels were low in subcutaneous tissue. The serum half-life of metronidazole was 9.0 +/- 1.6 h, of OH-metronidazole 14.8 +/- 7.4 h, and of tinidazole 16.4 +/- 3.8 h. The terminal-phase distribution volume was 35.8 +/- 10.01 for metronidazole and 40.6 +/- 9.91 for tinidazole, and the total body clearance 2.7 +/- 1.2 l/h and 1.8 +/- 0.5 l/h, respectively. The slower disposition of OH-metronidazole, which inhibits anaerobic bacteria, prolongs the duration of bioactivity in the body after metronidazole to that reached by tinidazole. OH-tinidazole was not detected in patient specimens (assay standards ensured that it could be assayed).(ABSTRACT TRUNCATED AT 250 WORDS)

Tinidazole milk excretion and pharmacokinetics in lactating women

Five women undergoing acute Caesarean section were given an i.v. dose of 1600 mg tinidazole preoperatively as prophylaxis against anaerobic infection. Blood and breast milk samples were collected at 8 and 4 h intervals, respectively, for 120 h. Tinidazole concentrations were measured by means of high performance liquid chromatography (h.p.l.c). The concentration of tinidazole in breast milk was highly related to the concentration in serum (r = 0.969). Tinidazole concentrations in serum declined monoexponentially with an average half-life of 11.4 h (range 8.7-13.1). The milk/serum concentration ratio varied between 0.62 and 1.39. Seventy-two hours after the Caesarean section the milk concentration exceeded 0.5 microgram/ml in only one woman. It may be calculated that at this time the maximum daily dose to the infant would be 0.1 mg/kg body weight (assuming 3.5 kg body weight and 400 ml milk consumed). We conclude that until tinidazole has been proven harmless to the neonate breast feeding following i.v. administration of 1600 mg should not be initiated earlier than 72 h after the dose.

A novel metabolite of tinidazole involving nitro-group migration

After oral doses to dogs of 14C-tinidazole, a 5-nitroimidazolyl antiprotozoal compound, a major and previously unidentified radioactive metabolite was isolated from urine and shown by FAB mass spectrometry and n.m.r. spectroscopy to be ring-hydroxylated. The exact identity of this metabolite was established by X-ray diffraction analysis as ethyl 2-(5-hydroxy-2-methyl-4-nitro-1-imidazolyl)ethyl sulphone. The apparent migration of the nitro group from the 5 position in the parent drug to the 4 position in the metabolite is a novel metabolic route.

Placental transfer of metronidazole and tinidazole in early human pregnancy after a single infusion

Concentrations of metronidazole and tinidazole were analysed in mother's serum, placental tissue and foetal tissue after a single intravenous infusion of 500 mg of either drug in 21 patients who underwent a first trimester legal abortion. At the time of the evacuation (60 min from the start of the infusion) the concentrations of metronidazole and tinidazole in serum were 13.6 +/- 0.6 micrograms/ml and 13.2 +/- 0.4 micrograms/ml, respectively. In foetal tissue the concentrations of metronidazole and tinidazole reached 66% and 58%, and in placental tissue 26% and 37%, of the respective serum values.

Prophylaxis with tinidazole in oral surgery. Tissue penetration and effect on the oral microflora

10 patients with odontogenic cysts were given 500 mg tinidazole orally every 12 h for infection prophylaxis before cystectomy. The administration started 48 h before operation and lasted for 7 days. Samples for assay of tinidazole were collected from blood plasma and cystic fluid during surgery. Saliva samples for microbiological studies of the normal flora were obtained before, during and after the antibiotic administration period. Mean concentrations of tinidazole in plasma and cystic fluid were 10.7 mg/l and 10.0 mg/l, respectively. The anaerobic flora was suppressed in all patients and two patients were colonized with enterobacteria, and two with fungi. No anaerobic bacterial strains resistant to tinidazole emerged during the treatment period. It is concluded that tinidazole can be administered prophylactically 48 h before oral surgery, in order to obtain maximal tissue concentration, without risk of the emergence of resistant bacterial strains or severe ecological disturbances of the oral microflora.

The pharmacokinetics of one single preoperative dose of metronidazole or tinidazole

Eight patients who were subjected to colorectal surgery received 1500 mg metronidazole and another 8 patients 1600 mg tinidazole. The two groups of patients were comparable in respect to age, body size, diagnoses, types of operations, premedication, and anaesthesia. Concentrations of the parent compounds and hydroxy-metronidazole were determined by high pressure liquid chromatography in serum and tissues (subcutaneous fat, rectus abdominal muscle, peritoneum, greater omentum, distal ileum, colon, appendix). The serum and tissue concentrations of metronidazole and tinidazole were within overlapping ranges. Hydroxy-metronidazole but not hydroxy-tinidazole was detected. The total area under the serum curves was 505 (SD: +/- 181) mg . h/l for metronidazole, 137 (+/- 38) mg . h/l for hydroxy-metronidazole, and 810 (+/- 286) mg . h/l for tinidazole. The serum half-life values in the same order were 8.5, 11.2, and 14.2 hours. The distribution volume (Vd,area) were 30.1 liter for metronidazole and 38.8 liter for tinidazole. The range of tissue concentrations were completely overlapping. The two regimens can, consequently, be assessed as pharmacokinetically similar.

Tinidazole pharmacokinetics in severe renal failure

The single-dose pharmacokinetics of intravenously and orally administered tinidazole were studied in normal subjects and patients with severe chronic renal failure. The clearance of tinidazole was also measured in patients on regular haemodialysis. After intravenous administration the mean elimination half-life of tinidazole was 17.1 +/- 2.3 (SD) hours in the normal subjects and 16.9 +/- 4.9 hours in patients with renal failure; the mean apparent volumes of distribution were 0.80 +/- 0.09 L/kg and 0.69 +/- 0.09 L/kg, respectively. Following oral administration the mean elimination half-life was 15.6 +/- 1.6 hours in the normal subjects and 18.4 +/- 3.5 hours in patients with renal failure; there were no statistically significant differences in these pharmacokinetic parameters. There was no accumulation of the major metabolite (hydroxymethyl tinidazole) in normal subjects or in patients with renal failure. Tinidazole clearance during haemodialysis was 71 +/- 7.7 ml/min. In the presence of renal failure no modification of tinidazole dosage would appear to be necessary. Tinidazole should be administered in full dosage following haemodialysis.

Quantification of the effect of anti-anaerobic drugs in experimental Bacteroides fragilis infection in mice

As a basis for the quantitation of the effect of anti-anaerobic drugs in vivo, an experimental thigh infection in mice was developed in which co-inoculation of Bacteroides fragilis and Escherichia coli is obligatory for proliferation of Bact. fragilis. The inhibitory effect of metronidazole and tinidazole on the proliferation of Bact. fragilis was assessed in this model. Both metronidazole and tinidazole showed a significant dose-effect relationship with respect to the outgrowth of Bact. fragilis but not that of E. coli. The effect of both drugs on Bact. fragilis was similar and at all dosage levels a significant correlation was found between the numbers of Bact. fragilis and E. coli.

Concentrations of metronidazole and tinidazole in abdominal tissues after a single intravenous infusion and repetitive oral administration

Concentrations of metronidazole and tinidazole in serum and abdominal tissues were determined after a single 500-mg intravenous infusion or after a 5-day oral dosage of 500 mg three times daily in groups of 10 patients each. In the patients who got the single infusions, the concentrations in tissues (except fat) reached almost the serum levels 10 min after the infusion. At 24 h, the tinidazole concentrations in serum averaged 3.2 micrograms/ml and those of metronidazole 1.3 micrograms/ml. In the patients who got the 5-day oral dosages, the steady-state levels of tinidazole in both serum and tissues were twice as high as those of metronidazole.

Pharmacokinetics of tinidazole in chronic renal failure and in patients on haemodialysis

The pharmacokinetics of tinidazole after infusion (800 mg in 15 min) were studied in 12 patients with chronic renal failure (RI) and in five patients undergoing regular dialysis treatment (RD). Tinidazole elimination plasma half-life was 15.09 +/- 0.68 h (mean +/- s.e. mean) (RI) and 12.9 +/- 1.0 h after dialysis (RD), but there was a significant decrease in half-life during dialysis (4.25 +/- 0.43 h) P less than 0.001). The apparent volume of distribution (0.64 +/- 0.03 l/kg) was equal to extra and intracellular water volume and tinidazole was little bound to plasma protein (8%). There was a slight sex difference in apparent volume of distribution between male patients (0.70 +/- 0.09 l/kg) and female patients (0.59 +/- 0.10 l/kg) (P = 0.07), but as body clearance decreases in the same order, there was no modification of plasma half-life. In renal failure, pharmacokinetics of tinidazole were not disturbed because no correlation between half-life, body clearance and creatinine clearance occurred; urine elimination was about 7% of administered dose. Plasma clearance during dialysis was 49.9 +/- 3.2 ml/min and about 43% of the available drug was eliminated during the 6 h dialysis procedure. These results suggest that an additional half-dose infusion should be given after the end of dialysis in patients undergoing regular dialysis treatment.

Comparative pharmacokinetics of metronidazole and tinidazole as influenced by administration route

Serum kinetics of metronidazole and tinidazole were compared in four separate randomized crossover studies. Single doses of each drug were given to healthy volunteers through intravenous infusion (500 mg over 20 min, six persons), by mouth (500 mg, nine persons), by rectum (1,000 mg, six persons), or intravaginally (500 mg, six persons). Concentrations of the unchanged drugs in serum, measured by high-pressure liquid chromatography, were similar after oral and intravenous administration, with mean peaks of 9.0 and 9.4 micrograms/ml for metronidazole and 7.5 and 10.1 micrograms/ml for tinidazole. Concentrations of tinidazole were significantly higher than those of metronidazole from 4 h onwards after intravenous infusion, and from 3 h onwards after administration by mouth. After rectal administrations, a significant difference was seen only at 48 h. After vaginal dosing, however, concentrations of metronidazole were significantly higher than those of tinidazole between 1.5 and 12 h. Bioavailability of either drug, calculated according to the formula (area under the curve for oral administration)/(area under the curve for infusion), was practically complete after oral administration and was poorer after rectal and especially vaginal administration. Whenever the parameters were calculable, the elimination half-life of tinidazole (range of means, 14.0 to 14.7 h) was significantly longer and total clearance (40.3 to 47.6 ml/min) was lower than the corresponding values of metronidazole (7.9 to 8.8 h and 71.8 to 80.1 ml/min, respectively).

Tinidazole--microbiology, pharmacology and efficacy in anaerobic infections

Tinidazole is a 5-nitroimidazole with selective activity against anaerobic bacteria and protozoa. It is bactericidal at low concentrations and its spectrum covers most anaerobic bacteria and some capnophilic microorganisms. Anaerobic bacteria known to be resistant to tinidazole include anaerobic streptococci, actinomyces and propionibacteria. Tinidazole is one of the most active antibacterial agents against Bacteroides fragilis which is one of the most resistant species of anaerobic bacteria. Only a few strains have been reported to be resistant. Tinidazole has been shown to be efficacious in protozoal infections such as trichomonal vaginitis, amoebiasis and giardiasis. Clinical studies have also shown that tinidazole is efficacious in the treatment of anaerobic infections including respiratory tract infections, intra-abdominal sepsis and obstetrical and gynecological infections. Since tinidazole has no activity against aerobic bacteria, it must be combined with other antibacterial agents in the treatment of mixed infections involving aerobic and anaerobic bacteria. Tinidazole has also been used successfully alone or in combination with other antimicrobial agents for prophylaxis in patients undergoing elective colonic and abdominal surgery, emergency appendectomy and gynecological surgery.

Serum and tissue tinidazole concentrations after intravenous infusion

Before appendectomy 36 adult patients were given an intravenous infusion of 500 mg of tinidazole. In the operation tissue samples were taken (blood, base of appendix vermiformis, muscle, fat) either 10, 20, 30, 60, or 120 min after cessation of infusion. The tinidazole concentrations were determined by liquid chromatography. The weight-standardized tinidazole concentrations in the serum, muscle tissue and appendix in all specimens were higher than the minimal inhibitory concentration (2 micrograms/g) of Bacteroides fragilis. The tinidazole concentrations of adipose tissue exceeded the limit of 1 microgram/g in all samples. The concentrations were high already in the 10-min patient group. The authors consider a tinidazole infusion started half an hour before the operation at a dose of 10 mg/kg of the patient's body weight to be a reliable procedure if the objective is to acquire a sufficient tissue concentration of tinidazole (2 micrograms/g) to prevent infection complications caused by anaerobic bacteria.

Penetration of metronidazole and tinidazole into the aqueous humor in man

500 mg of metronidazole or tinidazole were given as a 20-min infusion each to 10 patients who were hospitalized for elective cataract extraction. Metronidazole and tinidazole concentrations in aqueous humor were 5.2 +/- (SE) 0.5 and 5.3 +/- 0.7 micrograms/ml, respectively, 20-70 min after the end of the infusion. Aqueous humor/serum concentration ratios were 0.38 and 0.47 on the average for metronidazole and tinidazole, respectively.

Pharmacokinetics of tinidazole in male and female subjects

Tinidazole is a potent nitroimidazole compound active against, and used to treat, Trichomonas vaginalis infections in males and females. Speculation exists in the literature that observed differences in tinidazole plasma concentrations between males and females may be due to sex-mediated pharmacokinetic differences. To investigate this phenomenon, a study was designed to determine the pharmacokinetics of tinidazole in male and female subjects. Six male and six female volunteers were each administered a single 2-Gm oral dose of tinidazole. Plasma and urine samples, collected over a 72-hour period, were assayed by a sensitive and specific HPLC assay. Results demonstrate a significant correlation between tinidazole oral plasma clearance and body weight and apparent volume of distribution of tinidazole and body weight for male and female subjects, respectively. There were no apparent sex-mediated differences in weight-normalized pharmacokinetic parameters as documented by statistically equivalent mean oral plasma clearances (36.1 and 35.4 ml/kg/hour), apparent volumes of distribution (0.65 and 0.63 liter/kg), and elimination half-lives (12.3 and 12.3 hours, males and females, respectively). Mean area under the tinidazole plasma concentration-versus-time curve and mean peak plasma concentration of tinidazole were 1.3 times greater for females than for males, apparently due to the smaller mean body weight of females and consequently a 1.3 times greater administered dose to the females on a weight basis.

Tinidazole in anaerobic infections: a review of its antibacterial activity, pharmacological properties and therapeutic efficacy

Tinidazole, like the structurally-related drug metronidazole, was initially introduced for treating protozoal infections. However, both these nitroimidazole compounds are also active in vitro against most clinically important obligate anaerobes. Most of the clinical experience with tinidazole to date has involved prophylactic use to prevent postoperative anaerobic infection. Prospective placebo-controlled studies demonstrated that a single dose of tinidazole administered orally prior to elective colorectal surgery significantly reduced postoperative infection. Similarly, when given intravenously prior to appendectomy, tinidazole reduced the incidence of postoperative infection in some subgroups of patients. Although results of non-blinded studies with prophylactic tinidazole were encouraging when used in women undergoing gynaecological surgery (mainly hysterectomy), results from double-blind placebo-controlled studies in this situation have been somewhat equivocal. Thus, although the overall weight of evidence suggests that the drug is effective in this area of use, further study is needed to clarify its role in preventing anaerobic infection following gynaecological surgery compared with other antibiotics which can also be used for this purpose. Relatively few studies have been conducted with tinidazole in the treatment of established anaerobic infections, and this is an area needing further investigation. The drug is well tolerated when administered orally or intravenously.

[The effect of tinidazole on the anaerobic bacterial flora in patients undergoing gynecological surgery]

The various effects have been examined against the anaerobes by administering tinidazole when the operations of gynecology and obstetrics and the following results were obtained. 1. The serum concentrations after the single administration of 1,000 mg of TDZ showed 56.6 micrograms/ml of the peak value (3 hours) and 27.7 micrograms/ml of 24 hours value, and the antibacterial potency was maintained for a long duration. The concentration in the vaginal secretions was 21.8 micrograms/tampon within 24 hours. 2. The detections of anaerobes were made in 74 cases, before the administration, with the results of 1 case alone and 73 cases mixed with aerobes, 10 species and 133 strains being detected, which comprise 33 cases with 1 species, 27 cases with 2 species mixed, 10 cases with 3 species mixed and 4 cases with 4 species mixed. The main species detected were Bacteroides fragilis in 46 strains (34.6%), Peptostreptococcus spp. in 31 strains (23.3%) and Peptococcus spp. in 26 strains (19.5%). 3. The MIC values of the detected bacteria to the TDZ centered upon 0.78 micrograms/ml for Bacteroides fragilis, 3.13 micrograms/ml for Peptococcus spp. and 0.78 micrograms/ml for Peptostreptococcus spp. and those of the others were low, a lot of those being of sensitive strains. 4. The bacteriological effects on the anaerobes were, after the medication, observed to be 71.4% and found significantly more effective than 33.3% of natural eradication and decrease observed in the not administered group. 5. Clinically, no anaerobic infections were observed often operation and the therapeutical effects were observed. A little side effect was observed. 6. According to the above-mentioned results, it was observed possible to prevent from the anaerobic infections after operation in gynecology and obstetrics by administration of TDZ.

Liquid chromatographic assay for metronidazole and tinidazole: pharmacokinetic and metabolic studies in human subjects

We developed methods for measuring metronidazole, its two major metabolites, and tinidazole in serum and urine. After treatment of each sample with an equal volume of 5% perchloric acid, the drugs were separated by reverse-phase high-pressure liquid chromatography (retention times, 6 to 18 min). Quantitation was based on spectrometry at 320 nm. These assays were sensitive, rapid, and specific, and recoveries from biological samples were quantitative. Metronidazole and tinidazole were given as rapid intravenous infusions to four healthy human volunteers. The biological half-lives of these two compounds were 5.4 and 11.1 h, respectively. The hydroxy metabolite of metronidazole appeared quickly in serum and was eliminated at a slow rate. The acetic acid metabolite of metronidazole was detected in serum at very low levels and only for a limited time. No metabolic products of tinidazole were found in serum samples. In urine, 43.7% of the administered dose of metronidazole was recovered over a period of 24 h (24.1% of the dose as the hydroxy metabolite, 12.0% as the acetic acid metabolite, and 7.6% as unchanged drug). Only 18.4% of the infused dose of tinidazole was eliminated in urine over a period of 72 h, and no metabolic products were detected.

Nitroimidazoles in the canine prostate, vagina, and urethra

Diffusion of metronidazole and tinidazole in canine prostatic secretion was studied and compared to the diffusion of metronidazole into the canine vagina. This particular comparison was made because prostatic secretion represents an acidic environment in contrast to the canine vagina which has a basic pH. Metronidazole reached significantly higher concentrations in the prostatic secretion (PS) than in plasma (P). No differences were found in the concentrations of tinidazole in P and PS. Plasma and prostatic interstitial fluid (PIF) concentrations of both drugs showed no differences either. However, the PS/P and PIF/P ratios of metronidazole were significantly higher than the corresponding ratios of tinidazole. Metronidazole concentrations in the canine vagina and urethra were significantly lower than the plasma concentrations, possibly because of the basic pH environment. These findings suggest a possible advantage in using metronidazole over tinidazole in aerobic and Trichomonas vaginalis prostatitis and vaginitis in acidic environments. However, clinical studies comparing the two drugs should be carried out in order to establish if this is of clinical importance.

Single-dose metronidazole and tinidazole as therapy for giardiasis: success rates, side effects, and drug absorption and elimination

Eighty-five symptomatic patients with parasitologically confirmed, recently acquired giardiasis were treated in a comparative trial of 2.4 g of metronidazole either once or on two successive days or 2.0 g of tinidazole once. The follow-up period was eight weeks; the parasitological follow-up consisted of 871 stool and 30 duodenal specimens. Reinfections were unlikely. The rates of success were: metronidazole, single dose, 13 of 26; metronidazole, two doses, 24 of 31; and tinidazole, single dose, 26 of 28. Clinical and parasitological effects were parallel in nearly all cases. Tinidazole was more effective, produced fewer side effects, and was recommendable as the drug of choice in single-dose therapy. Pharmacokinetic explanations for therapeutic failure was sought with use of a bioassay of drug concentrations in serum. The outcome of therapy was not related to serum levels at 1hr or 24 hr, or to the rate of elimination. The mean serum half-lives of active metronidazole and tinidazole were 9.5 and 13.0 hr, respectively.

Aspects of the pharmacology and pharmacokinetics of nitroimidazoles with special reference to tinidazole

Tinidazole has been reported to be highly effective against trichomoniasis, giardiasis and amoebiasis. In vitro, tinidazole is more active against trichomonads than metronidazole and possesses antiprotozoal activity at least comparable to metronidazole against Entamoeba histolytica, Tinidazole gives higher serum levels in animals following oral administration than metronidazole and is well distributed in organs and tissues. When tinidazole or metronidazole is given to healthy volunteers at a dose of 2g orally, the serum level of tinidazole at 48h is considerably higher than that of metronidazole. At 72h tinidazole is still present but metronidazole is not. These pharmacokinetic differences result from the longer half-life of tinidazole. These findings suggest that tinidazole might prove to be more useful than metronidazole in the treatment of protozoal infections when given in once daily oral doses of 2g.

Concentrations of tinidazole in body fluids and tissues in gynaecological patients

The concentrations of tinidazole in various tissues and body fluids were studied in gynaecological patients after a single 2g oral dose. Tinidazole was determined by the agar-diffusion technique using a strain of Clostridium bifermentans. Reliable estimates of concentrations down to 0.5 microng/ml could be obtained. Dichloromethane extraction of tinidazole added to various tissues in known amounts gave a recovery of 100 +/- 10%. Peak serum values of 32-52 microng/ml were reached 3-6h after the administration. The concentrations in peritoneal fluid, obtained at operation 8.5-15h after the intake, varied between 16 and 40 microng/ml. Specimens from the Fallopian tubes yielded 15-26 microng tinidazole/g tissue; similar levels were obtained specimens from myometrium, endometrium, portio, vaginal secretions, omental fat, and cutis. It is concluded that, with the given dose, tinidazole concentrations are achieved in fluids and tissues of the female genital tract that are far in excess of those that should be therapeutical in infections caused by microorganisms know to respond to nitroimidazole treatment.

[Height of children with G. lamblia and there capacity to absorb d-xylose]

The investigation was carried out with the purpose of studying the capacity to absorb d-xylose in children with G. lamblia establishing also, whether or not their height was reduced. The study is included 25 school age children with giardiasis, pairing them according to sex and age with another 25 without intestinal parasitosis.

Tinidazole: a review of its antiprotozoal activity and therapeutic efficacy

Tinidazole, a synthetic imidazole derivative, has been used in the oral treatment of several protozoal infections - trichomoniasis, giardiasis and amoebiasis. Among the protozoal organisms inhibited by tinidazole are Trichomonas vaginalis, Trichomonas foetus, and Entamoeba histolytica. In vitro, tinidazole has been shown to possess antiprotozoal activity at least comparable to, and in some cases greater than, metronidazole. Tinidazole also has activity against some Gram-negative anaerobic bacilli, including Bacteroides spp. Following oral administration of a 2g dose, like metronidazole serum levels peak in about 2 hours but persist for longer. Any clinical significance of the longer plasma half-life (tinidazole 12.5h; metronidazole 7.3h) has yet to be demonstrated. Tinidazole is approximately 20% bound to plasma proteins. Only unchanged drug has been found in the plasma and urine of tinidazole-treated subjects, although metabolites have been detected in animal studies. A single 2g dose of tinidazole has been shown to be effective therapy in vaginal trichomoniasis and in urogenital trichomoniasis in males. Single-dose therapy in general offers advantages in regard to convenience, and in the treatment of a sexually transmissible disease such as trichomoniasis, single-dose therapy facilitates compliance of patient and sexual partner. In comparative studies, tinidazole, in both single-dose and traditional multiple-dose regimens, has been shown to be equivalent and often superior to other antitrichomonal agents, including metronidazole. In intestinal amoebiasis, tinidazole has been evaluated after both once-a-day and multiple daily dose regimens, with the former giving slightly better results. When both metronidazole and tinidazole were administered in multiple daily dose regimens, the two agents yielded similar cure rates; in one study fewer tinidazole-treated patients required a second course. Tinidazole has also been successful in some cases of amoebic liver abscess, but an advantage over metronidazole has not been demonstrated. Results in the treatment of giardiasis, especially with the single-dose regimen, are promising, and in one study, tinidazole proved effective in infections resistant to metronidazole. Even in large doses, tinidazole has been well tolerated, although rarely vomiting may occur and the patient may need to be re-treated with a multiple dose regimen.