Sensitive inexpensive chromatographic determination of an antimicrobial combination in human plasma and its pharmacokinetic application.

This study represents simple inexpensive chromatographic determination of ciprofloxacin (CIP) and tinidazole (TIN) simultaneously in human plasma using HPLC-DAD followed by a pharmacokinetic application. C18 column was used as stationary phase with isocratic elution of a mobile phase composed of acetic acid solution (2%) and acetonitrile (85: 15, v/v) and ornidazole as internal standard (IS) with UV detection at 318 nm. The two drugs and the IS were separated at 6.55, 7.91 and 11.07 min for CIP, TIN and IS, respectively, with good selectivity and sensitivity for their analysis in presence of plasma matrix components and the drugs' metabolites. Sample preparation involved only protein precipitation without any complicated extraction procedures decreasing analysis time. For method validation, FDA regulations for analysis in biological fluids were followed. Pharmacokinetic (PK) study on six healthy volunteers was conducted after single oral dose administration of 500 and 600 mg of CIP and TIN, respectively. Dugs' plasma levels were followed for 12 or 72 h post dosing for CIP and TIN, respectively, and different PK data for the two drugs were calculated and they were comparable to the reported values demonstrating successful future application of the presented method in PK, bioequivalence and bioavailability studies.

A simple high-performance liquid chromatographic method for the determination of brazilin and its application to a pharmacokinetic study in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Caesalpinia sappan is a medicinal plant native to China popularly used to treat chronic pelvic inflammation, dysmenorrhea and hysteromyoma. Its main bioactive component is brazilin which had presented antibacterial, anti-inflammatory and anti-platelet aggregation activities. To establish a sensitive, selective, reproducible, and accurate high performance liquid chromatographic (HPLC) method for the quantitative determination of brazilin in plasma, and study the pharmacokinetics of brazilin in rats after intravenous administration of brazilin. MATERIALS AND METHODS: Rats received intravenous injection of 25, 50 and 100mg/kg of brazilin. Concentrations of brazilin in plasma were determined by HPLC method at different time points and all pharmacokinetic parameters were estimated by non-compartmental analysis with WinNonLin 6.2 software. RESULTS: After single intravenous doses of 25, 50 and 100mg/kg brazilin in rats, the main PK parameters were as follows: Cmax were 18.1 ± 4.1, 46.7 ± 8.7 and 82.2 ± 9.6 µg/mL; AUC0-24 were 20.4 ± 4.3, 48.7 ± 6.8 and 90.4 ± 10.3 µgh/mL; and t1/2 were 5.4 ± 1.5, 5.8 ± 0.9 and 6.2 ± 1.2h, respectively. CONCLUSION: It showed that the brazilin was eliminated moderately in rat by intravenous injection route with t1/2 of 6h and showed a dose-dependence profile of Cmax and AUC0-24 at the doses of 25~100mg/kg of brazilin for injection in rats.

Chitosan-sodium alginate blended polyelectrolyte complexes as potential multiparticulate carrier system: colon-targeted delivery and gamma scintigraphic imaging.

OBJECTIVES: The objective of this study is to develop stable, biodegradable chitosan-sodium alginate-based dual, ionic cross-linked multiparticulate system (microbeads) of tinidazole for targeted colon delivery and sustained drug release for the treatment of amoebiasis and thereby evaluating its targeting approach through in vivo gamma scintigraphic imaging technique. METHODS: The chitosan-sodium alginate-based multiparticulate system developed was producing sustained effect by virtue of its mechanical strength using double ionotropic gelation method utilizing calcium chloride and sodium sulfate as first and second cross-linkers respectively. Prepared formulations were evaluated for percent yield, drug entrapment efficiency, particle size, degree of swelling, in vitro kinetics, and in vivo targeting potentials using gamma scintigraphic imaging technique. RESULTS: The obtained particulates were spherical, free flowing, and had a mean particle size ranging from 1.422 mm to 1.881 mm, whereas percent yield and percent drug entrapment efficiency was found to be in between 72.61 to 82.43% and 63.25 to 79.32% respectively. CONCLUSION: The prepared multiparticulate system showed better sustained release property and in vivo ability to target colon for drug delivery. Hence, the developed multiparticulate system could be a promising device to achieve greater site-specificity to colon.

Development of a HPLC/MS/MS method for simultaneous determination of tinidazole, dyclonine and chlorhexidine in rat plasma and its application in the pharmacokinetic research of a film-forming solution.

A rapid and sensitive HPLC/MS/MS method was developed and validated for simultaneous determination of tinidazole, dyclonine and chlorhexidine, the three main components of a film-forming solution, in rat plasma. The plasma samples were pretreated by solid phase extraction (SPE) method. Separation was achieved on a Phenomenex Gemini C(18) column (50 mm × 2.0 mm, 5 µm) using an isocratic mobile phase system composed of methanol-ammonium formate (10 mM)-formic acid (56:44:0.2, v/v/v) (pH 3.5) at a flow rate of 0.2 mL/min. Analytes were determined by tandem mass spectrometry with electrospray positive ionization and multiple-reaction monitoring (MRM) mode. The monitoring ions were (m/z) 247.4 → (m/z) 81.9 for tinidazole, (m/z) 290.1 → (m/z) 97.8 for dyclonine, (m/z) 505.0 → (m/z) 335.3 for chlorhexidine and (m/z) 282.1 → (m/z) 212.0 for phentolamine (internal standard). The calibration curves were linear in the range of 2-1000 ng/mL for the three components. The precision and accuracy of the method were well within the generally accepted criteria for biomedical analysis. It has been successfully applied to the pharmacokinetic research of a film-forming solution in rat.

[Preparation and in vitro and in vivo study on tinidazole in situ forming sustained-release injection].

This study is to prepare the in situ forming sustained-release injection which can perform sustained release behavior at the periodontal site for 7 days and to evaluate its in vitro and in vivo properties. After preparation of in situ forming sustained-release injection the in situ time was studied. And the surface of the solid injection was characterized by SEM. The rheological curve at 0 degrees C, 25 degrees C, 37 degrees C was determined and the impact of the temperature on the viscosity was examined. The in vitro release behavior was investigated. At last, rabbit periodontitis model was established to study its pharmacokinetics. The injection was stable, hard to stratify and decompose. The in situ forming time was about 6 seconds. It can easily adhere into periodontal pockets. There were lots of holes on the surface of the solid injection for the drug to diffuse. The drug releasing curves could be fit by Korsmeyer-Peppas equation. The drug smoothly released for 7 days at pH 7.4 PBS buffer with a very slight burst release and maintained a certain concentration. In vivo pharmacokinetics results indicated that after administration with the in situ forming injection, achievement of tinidazole (TNZ) concentration in gingival crevicular fluid (GCF) was more comparable and long-lasting than usual solution of TNZ management and relatively constant TNZ levels were attained until 168 h. All these results supported the prospect of tinidazole in situ forming sustained-release injection in clinical applications.

Pharmacokinetics of Tinidazole in Chinese subjects: comparison of Mongolian, Korean, Hui, Uighur and Han nationalities.

PURPOSE: This study investigated the pharmacokinetics of tinidazole in subjects of five different Chinese nationalities (Han, Mongolian, Korean, Hui, and Uighur). METHODS: Fifty healthy subjects (five male and five female of each nationality) were recruited for the study, and each received 1 g tinidazole. A total of 14 blood samples were collected over a 72-hour period after administration. RESULTS: Pharmacokinetic profiles, including area under the curve from time zero to infinity (AUC0-inf), peak plasma concentration (Cmax), time to reach Cmax (tmax), oral clearance (CL/F), elimination rate constant (Ke), and elimination half-life (t1/2), were determined following a single oral dose of tinidazole. The respective pharmacokinetic properties of Han, Mongolian, Korean, Hui, and Uighur nationalities were: half-life (h): 16.94+/-2.40, 16.40+/-1.79, 16.63+/-1.82, 16.81+/-1.56, 14.34+/-1.92; Cmax (microg/mL): 19.04+/-2.42, 19.22+/-4.93, 20.83+/-3.33, 20.25+/-4.05, 18.81+/-3.10; AUC0-inf (h*microg/mL): 483.13+/-65.65, 479.70+/-99.74, 511.07+/-53.47, 514.25+/-130.78, 388.58+/-37.37. The t1/2 and AUC0-inf of Uighur subjects were significantly lower (p =0.023, 0.011) and the CL/F and Ke were significantly higher (p = 0.003, 0.013) than those of other nationalities. After normalization by weight, the differences in AUC0-inf and CL/F between Uigur subjects and those of other races were still significant. CONCLUSIONS: The results indicate that ethnicity had significant impact on the pharmacokinetics of tinidazole after a single oral dose in healthy volunteers of different nationalities in China.

Why not revisiting tinidazole as potential treatment of odontogenic infections?

Tinidazole is a 5-nitroimidazole initially introduced intoclinical medicine in 1969 for the treatment of unicellular parasites.Tinidazole offers selective bactericidal activity, not influencedby the inoculum size, against anaerobic bacteria,that make it of theoretical interest against periodontopathogeninfections. This article reviews the required characteristicsof an antibiotic directed to odontogenic anaerobic infections,as well as the pharmacodynamic pitfalls of commonantibiotic treatments. In addition the in vitro, pharmacokineticand pharmacodynamic properties of tinidazole are reviewed,assessing the degree of its adhesion to the required characteristics,as well as identifying the gaps to be fulfilled priorto its use in this medical field. Tinidazole offers interestingcharacteristics making worthy investigations as a candidatefor the treatment of anaerobic odontogenic infections (AU)

El tinidazol es un 5-nitroimidazol que se introdujo en1969 en la clínica para el tratamiento de infestaciones porparásitos unicelulares. El tinidazol ofrece una actividadbactericida selectiva, no influida por el tamaño del inóculo,frente a bacterias anaerobias, por lo que presenta un interésteórico en infecciones producidas por odontopatógenos. Esteartículo revisa las características que requiere un antibióticodirigido al tratamiento de infecciones odontogénicas por bacterias anaerobias, así como las carencias farmacodinámicasde los antibióticos habitualmente utilizados en estetipo de infecciones. Asimismo se revisan las propiedades invitro, farmacocinéticas y farmacodinámicas de tinidazol,valorándose el grado de adhesión de este compuesto a lascaracterísticas requeridas para un antibiótico dirigido a estetipo de infecciones. También se identifican las lagunas deconocimiento sobre tinidazol que deben resolverse antes desu utilización en este campo. Tinidazol ofrece unas característicasinteresantes que posibilitan realizar investigacionescomo candidato al tratamiento de infecciones odontogénicasanaerobias (AU)

Bioequivalence evaluation of two different tablet formulations of tinidazole in healthy volunteers.

The bioequivalence of two different tablet formulations of tinidazole (CAS 19387-91-8) was determined in healthy volunteers after a single dose in a randomized crossover study, with a 1-week washout period between the doses. Reference and test products were administered to 24 volunteers with 240 mL water after overnight fasting. Plasma concentrations of tinidazole were monitored by a high-performance liquid chromatographic method (HPLC) over a period of 72 h after the administration. The pharmacokinetic parameters AUC(o-t), AUCo-infinity, C(max), T(max), T((1/2)el) and beta were determined from plasma concentration time profile of both formulations and found to be in good agreement with previously reported values. The calculated pharmacokinetic parameters were compared statistically to evaluate bioequivalence between the two brands. The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals for the ratio of C(max) (93.9 -102.6%), AUC(o-t) (94.9-101.1%) and AUC(o-infinity) (94.6-100.8%) values for the test and reference products were within the 80-125% interval, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration Guidelines. These results Indicate that the test and the reference products of tinidazole are bioequivalent and, thus, may be prescribed interchangeably.

Tinidazole for the treatment of vaginal infections.

Tinidazole has been used for vaginal infection worldwide but not in the US for > 40 years. Recently, tinidazole has been re-introduced and approved by the FDA for trichomoniasis and restudied as an alternative to metronidazole for bacterial vaginosis. In vitro antimicrobial activity and pharmacokinetics studies indicate that tinidazole has minor but possibly relevant antimicrobial as well as pharmacokinetic advantages when compared directly with metronidazole. Clinical comparison has been infrequent although the limited head-to-head studies indicate minimal therapeutic advantage with tinidazole. Perhaps the more relevant differences relate to the enhanced tolerance and reduced toxicity of tinidazole. Ongoing, as yet incomplete, studies directly comparing the clinical efficacy of metronidazole and tinidazole for bacterial vaginosis should clarify the status of tinidazole; however, cure rates are unlikely to be significantly different. Although uncommon, high-level trichomonal metronidazole resistance can be reliably cured by using tinidazole, which is an invaluable advantage.

In vivo and real time determination of ornidazole and tinidazole and pharmacokinetic study by capillary electrophoresis with microdialysis.

The aim of this study was to develop a rapid and sensitive method for in vivo and real time monitoring unbound ornidazole (ONZ) and tinidazole (TNZ) in rabbit blood using capillary electrophoresis coupled with microdialysis. The UV wavelength was set at 214 nm and all separations were performed in 20 mM Tris-H3PO4 (pH 1.5) buffer. Microdialysis probes were perfused at 4 microl/min resulting in relative recoveries of 33.1+/-3.6% and 34.8+/-3.3% (n=3) for ONZ and TNZ, respectively. The linearity was studied in the concentration range of 1.0-412 microg/ml for ONZ and 1.0-520 microg/ml for TNZ. The detection limits were 0.7 microg/ml for ONZ and 0.6 microg/ml for TNZ (S/N=3). All separation could be achieved within 15 min. This method has been successfully applied to the pharmacokinetic study of ONZ and TNZ in rabbit blood.

Tinidazole: from protozoa to Helicobacter pylori--the past, present and future of a nitroimidazole with peculiarities.

Tinidazole (Fasigyn, Pfizer Ltd), like metronidazole - to which it is structurally related - was initially introduced for treating protozoal infections. However, both of these nitroimidazole compounds are active against most clinically important obligate anaerobes. In the last few years, the discovery of Heliobacter pylori and of its susceptibility to nitroimidazoles focused new attention on these drugs. Tinidazole, as a part of this class of drugs, shares the characteristics and indications of other nitroimidazoles. However, it has a number of desirable features that could potentially make it very successful: a better pharmacokinetic and pharmacodynamic profile, a better safety and tolerability spectrum, and a preserved activity against some bacteria that are resistant to metronidazole.

[Non-equilibrium properties of drug permeation through stratum corneum in vitro].

AIM: To illustrate the non-equilibrium properties of drug permeation through stratum corneum (SC) to provide theory and method for transdermal drug delivery. METHODS: The system of side-by-side permeation chambers in vitro was isolated, thus conditions for equilibrium state were decided. And a network thermodynamic model was established. Non-equilibrium and leakage experiments were completed with which tinidazole was pattern drug. RESULTS: The properties of non-equilibrium including: long term to reach equilibrium state; delay-start of the permeation; uncertainty of initial drug permeable flux. The properties of leakage including: degression of drug permeable flux; changeability of permeation time constant. CONCLUSION: The permeation cell is believed to be a non-linear and time variable system.

An in vitro study of the susceptibility of mobile and cystic forms of Borrelia burgdorferi to tinidazole / Estudio in vitro de la susceptibilidad de las formas móviles y císticas de Borrelia burgdorferi al tinidazol

The susceptibility of mobile and cystic forms of Borrelia burgdorferi to tinidazole (TZ) was examined. The minimal bactericidal concentration (MBC) of TZ against the mobile spirochetes was >128 microg/ml at 37 degrees C in micro-oxic atmosphere when incubated for 14 days. TZ significantly reduced the conversion of mobile spirochetes to cystic forms during incubation. The MBC for older (10-months-old) cysts at 37 degrees C in a micro-oxic atmosphere was >0.5 microg/ml, but >0.125 microg/ml for young (1-day-old) cysts. Acridine orange staining, dark-field microscopy and transmission electron microscopy revealed that, when the concentration of TZ was > or = MBC, the contents of the cysts were partly degraded, core structures did not develop inside the young cysts, and the amount of RNA in these cysts decreased significantly. When cysts were exposed to TZ, both the spirochetal structures and core structures inside the cysts dissolved, and the production of blebs was significantly reduced. These observations may be valuable in the treatment of resistant infections caused by B. burgdorferi, and suggest that a combination of TZ and a macrolide antibiotic could eradicate both cystic and mobile forms of B. burgdorferi (AU)

Este estudio examina la susceptibilidad al tinidazol (TZ) de las formas móviles y císticas de Borrelia burgdorferi. La concentración bactericida mínima (CBM) de TZ para las espiroquetas móviles era >128 mg/ml a 37°C en atmosfera microóxica e incubación durante 14 días. El TZ redujo significativamente la conversión de espiroquetas móviles a la forma cística durante la incubación. La CBM para los cistos viejos (de 10 meses) a 37°C y en atmosfera microóxica era >0.5 mg/ml, mientras para los cistos jóvenes (de un día) era >0.125 mg/ml. La tinción con naranja de acridina, la microscopia de campo oscuro, y la microscopia electrónica de transmisión mostraron que cuando la concentración de TZ era ≥MBC el contenido de los cistos se degradaba parcialmente, no se desarrollaban las estructuras nucleares en el interior de los cistos jóvenes, y la cantidad de RNA en dichos cistos disminuía significativamente. Cuando los cistos se exponían a TZ, las estructuras espiroquetales y nucleares de su interior se disolvían, y la producción de vesículas se reducía significativamente. Estas observaciones pueden ser importantes en el tratamiento de infecciones resistentes causadas por B. burgdorferi, y sugieren que la combinación de TZ con un antibiótico macrólido podría erradicar tanto las formas císticas de B. burgdorferi como las móviles (AU)

HPLC and LC-MS studies on stress degradation behaviour of tinidazole and development of a validated specific stability-indicating HPLC assay method.

The objective of the current investigation was to study the degradation behaviour of tinidazole under different ICH recommended stress conditions by HPLC and LC-MS, and to establish a validated stability-indicating HPLC method. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal decomposition. Extensive degradation was found to occur in alkaline medium, under oxidative stress and in the photolytic conditions. Mild degradation was observed in acidic and neutral conditions. The drug was stable to thermal stress. Successful separation of drug from degradation products formed under stress conditions was achieved on a C-18 column using water-acetonitrile (88:12) as the mobile phase. The flow rate was 0.8 ml x min(-1) and the detection wavelength was 310 nm. The method was validated with respect to linearity, precision, accuracy, specificity and robustness. The utility of the procedure was verified by its application to marketed formulations that were subjected to accelerated stability studies. The method well separated the drug and degradation products even in actual samples. The products formed in marketed liquid infusions were similar to those formed during stress studies.

Pharmacokinetic evaluation of guar gum-based colon-targeted drug delivery systems of tinidazole in healthy human volunteers.

The aim of the present investigation was to determine the in vivo availability of guar gum-based colon-targeted tablets of tinidazole in comparison with immediate release tablets of tinidazole in human volunteers. Six healthy volunteers participated in the study, and a cross-over design was used. The plasma concentration of tinidazole was estimated by HPLC. The pharmacokinetic parameters were calculated from the plasma concentration of tinidazole versus time data. The immediate release tablets of tinidazole produced a peak plasma concentration (Cmax of 3239 +/- 428 ng/ml) at 1.04 +/- 0.32 hr (Tmax), whereas colon-targeted tablets produced peak plasma concentration (Cmax of 2158 +/- 78 ng/ml) at 14.9 +/- 1.6 hr. The delayed Tmax, decreased Cmax, and Ka, and unaltered bioavailability and elimination half-life of tinidazole from guar gum-based colon-targeted tinidazole tablets, in comparison with the immediate tablets, indicated that the drug was not released in the stomach and small intestine but delivered to the colon. Slow absorption of the drug from the less absorptive colon might result in the availability of the drug for local action in the colon. The guar gum-based colon-targeted tablets of tinidazole may be useful in providing an effective and safe therapy of intestinal amoebiasis.

[Oleyl pyroglutamate for use as transdermal enhancer and its enhancing mechanism].

AIM: To test the enhancing activity and the mechanism of oleyl pyroglutamate used as transdermal enhancer. METHODS: The penetration-enhancing effects of oleyl pyroglutamate, oleyl alcohol and oleic acid on the three drugs (caffeine, tinidazole and cortisone) were observed; the transdermal enhancing mechanism of oleyl pyroglutamate was studied with the attenuated total reflectance Fourier-transfer infrared spectroscopy(ATR-FTIR) of the human stratum corneum in vivo. RESULTS: The penetration-enhancing ratio of the three drugs was 7.9 fold, 41.8 fold and 2.8 fold, respectively. The absorptions at 2,800-2,950 cm-1 and 1,642-1,646 cm-1 (amide-I) in the ATR-FTIR spectrum of the stratum were found to be shifted differently following removal of the stratum corneum which was treated with oleyl pyroglutamate. CONCLUSION: Oleyl pyroglutamate showed better penetration-enhancing effect on the penetration of drugs. Its transdermal enhancing mechanism may be that oleyl pyroglutamate induced not only disordering of the stratum corneum lipid, but also change of the secondary structure of keratin.

A novel pH- and time-dependent system for colonic drug delivery.

A novel pH- and time-dependent delivery system was developed for delivering drugs to the colon. In vitro studies showed that this novel system could release the drug at a predetermined time, which was mainly controlled by the coating layers of the system. The delayed time of the press-coating layer was controlled by its erosion rate, which followed Hixson-Crowell equation. A proper selection of such factors as the viscosity grade of HPMC and tablet hardness, etc., can help reproduce the drug release profile as expected. The transit profiles in two healthy volunteers by gamma scintigraphy demonstrated that the tablets were able to pass through the stomach and small intestine intact and could safely reach the distal end of the small intestine, where the system began to release the drug contained in the core tablet. For both of the volunteers, disintegration of the tablets occurred in the ascending colon, which had highlighted the potential of this system for colonic drug delivery.

Validated HPLC method for the determination of tinidazole in human serum and its application in a clinical pharmacokinetic study.

A high performance liquid chromatographic (HPLC) method for the determination of tinidazole in human serum using metronidazole as internal standard (IS) is described. Protein precipitation is used for the preparation of sample. Mobile phase consisting of 0.002 M phosphate buffer, methanol and acetonitrile mixture (85:7.5:7.5/v/v/v) was used at a flow rate of 1 ml/min on a C18 column. The eluate was monitored using an UV/Vis detector set at 320 nm. Ratio of peak area of analyte to IS was used for quantification of serum samples. The absolute recovery was greater than 95% over a concentration range of 0.5 to 30 micrograms/ml and the limit of quantitation was 0.05 microgram/ml. The intra-day relative standard deviation (RSD) measured at 0.5, 5, 15 and 30 micrograms/ml ranged from 0.36 to 6.14%. The inter-day RSD ranged from 1.14 to 4.21%. The method is simple, sensitive and has been successfully used in a pharmacokinetic study conducted in healthy human volunteers.

CLINICAL EFFICACY OF BIODEGRADABLE DENTAL IMPLANTS OF TINIDAZOLE IN PERIODONTITIS.

Dental implants of tinidazole were formulated using poly (ε-caprolactone), a biodegradable polymer and evaluated. Clinical evaluation was carried out in ten patients with acute peridontitis. Various clinical parameters viz., gingival index, plaque score, attachment gain, reduction in pocket depth were evaluated after 10, 20, 30 and 40 days of treatment and compared with placebo as control. There was significant improvement in the healing of periodontal pockets treated with tinidazole implants as compared to the control sites. Estimation of tinidazole in gingival crevicular fluid (GCF) revealed that the drug levels above the minimum inhibitory concentration (5.9 µg/mg) for many of the periodontal pathogens was maintained throughout the period of study (40 days). This confirms the clinical efficacy of the dose and the duration of the study. It was found that biodegradable carrier was better accepted than the non-biodegradable carriers reported earlier.