Overview of Analytical Methods for Evaluating Tinidazole.

BACKGROUND: Tinidazole (TIN) has amoebicidal, giardicidal, antifungal, and antimicrobial activities. It is marketed in the form of tablets. Analytical methods to assess the quality of TIN-based products are essential for correct pharmacotherapy. OBJECTIVE: The objective of this review is to show an overview of the existing analytical methods for evaluating TIN, according to the quality control (QC) analysis routine and green analytical chemistry (GAC). RESULTS: Official compendia show a method for evaluating TIN in tablets by nonaqueous titration, which has limitations (materials on the mg scale using solvents considered not recommended and harmful). The literature shows some analytical methods for evaluating TIN, both physicochemical and microbiological. The most used physicochemical method is UV (41%), and second is HPLC (28%). Among the microbiological methods, agar diffusion and turbidimetric methods are equally divided. The most studied matrix is TIN tablets (73%), and the most used solvent is methanol. CONCLUSIONS: The literature shows space for the development of analytical methods according to GAC for evaluating TIN, optimizing time, resources, and materials, reducing waste generation, and opting for less aggressive reagents, solvents, and diluents. HIGHLIGHTS: This review shows the status of analytical methods, both physicochemical and microbiological, for the analysis of TIN in pharmaceutical matrix, in the context of routine analysis of the chemical-pharmaceutical industries and of GAC.

Digitally enhanced thin layer chromatography for simultaneous determination of norfloxacin and tinidazole with the aid of Taguchi orthogonal array and desirability function approach: Greenness assessment by analytical Eco-Scale.

In this study, an eco-friendly fast simple method was developed for simultaneous determination of norfloxacin and tinidazole based on thin-layer chromatography and image-processing analysis. The binary mixture was separated using reversed phase - thin layer chromatography plates and 30% trifluoroacetic acid only as mobile phase. Mobile phase composition was optimized using Taguchi orthogonal array and Derringer's desirability function. The plates were viewed under UV lamp and photographed by iPhone camera followed by image processing with Fiji software using integrated density as the measured response. As decreasing illumination increases the sensitivity of the method, this method was applied on two different ranges for each drug. The first one was 0.6-6.0 and 0.9-9.0 µg/spot for norfloxacin and tinidazole, respectively measured on the original image with normal illumination. The second one was measured after decreasing the illumination of the captured images at 0.06-0.60 and 0.09-0.90 µg/spot for norfloxacin and tinidazole, respectively. The proposed method was successfully applied for the determination of both drugs in tablets dosage form without interference from the commonly encountered excipients. Analytical Eco-Scale was used to evaluate the greenness profile of the proposed method and it was found to be excellent green analytical method.

HPTLC method for Simultaneous Determination of Norfloxacin and Tinidazole in presence of Tinidazole Impurity.

Sensitive, selective and accurate high-performance thin layer chromatographic HPTLC method for quantitative determination of Norfloxacin (NF), Tinidazole (TZ) and 2-Methyl-5-nitroimidazole (MNZ) as potential impurity of Tinidazole is developed and validated in the presented work. Calibration curves were linear over the concentration ranges of 0.4-2.4, 0.4-1.6, 0.2-1.2 µg/band for NF, TZ and MNZ, respectively. The method depends on separation and quantitation of NF, TZ and MNZ on aluminium plates pre-coated with silica gel HPTLC 60F254 as stationary-phase using chloroform: methanol: formic acid (7.5:1: 0.3, by volume) as developing system followed by densitometric measurement of bands at 298 nm. The developed method was validated and proved to meet the requirements delineated by ICH guidelines with respect to linearity, accuracy, precision, specificity and robustness. The validated method was successfully applied for determination of studied drugs in bulk powders and in their pharmaceutical formulation indicating the ability of proposed method to be used for routine quality control analysis of these drugs.

Preparation and application of a carbon paste electrode modified with multi-walled carbon nanotubes and boron-embedded molecularly imprinted composite membranes.

An innovative electrochemical sensor was fabricated for the sensitive and selective determination of tinidazole (TNZ), based on a carbon paste electrode (CPE) modified with multi-walled carbon nanotubes (MWCNTs) and boron-embedded molecularly imprinted composite membranes (B-MICMs). Density functional theory (DFT) calculations were carried out to investigate the utility of template-monomer interactions to screen appropriate monomers for the rational design of B-MICMs. The distinct synergic effect of MWCNTs and B-MICMs was evidenced by the positive shift of the reduction peak potential of TNZ at B-MICMs/MWCNTs modified CPE (B-MICMs/MWCNTs/CPE) by about 200 mV, and the 12-fold amplification of the peak current, compared with a bare carbon paste electrode (CPE). Moreover, the coordinate interactions between trisubstituted boron atoms embedded in B-MICMs matrix and nitrogen atoms of TNZ endow the sensor with advanced affinity and specific directionality. Thereafter, a highly sensitive electrochemical analytical method for TNZ was established by different pulse voltammetry (DPV) at B-MICMs/MWCNTs/CPE with a lower detection limit (1.25 × 10-12 mol L-1) (S/N = 3). The practical application of the sensor was demonstrated by determining TNZ in pharmaceutical and biological samples with good precision (RSD 1.36% to 3.85%) and acceptable recoveries (82.40%-104.0%).

Validated spectrophotometric methods for simultaneous determination of Omeprazole, Tinidazole and Doxycycline in their ternary mixture.

A comparative study of smart spectrophotometric techniques for the simultaneous determination of Omeprazole (OMP), Tinidazole (TIN) and Doxycycline (DOX) without prior separation steps is developed. These techniques consist of several consecutive steps utilizing zero/or ratio/or derivative spectra. The proposed techniques adopt nine simple different methods, namely direct spectrophotometry, dual wavelength, first derivative-zero crossing, amplitude factor, spectrum subtraction, ratio subtraction, derivative ratio-zero crossing, constant center, and successive derivative ratio method. The calibration graphs are linear over the concentration range of 1-20 µg/mL, 5-40 µg/mL and 2-30 µg/mL for OMP, TIN and DOX, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and successfully applied to commercial pharmaceutical preparation. The methods that are validated according to the ICH guidelines, accuracy, precision, and repeatability, were found to be within the acceptable limits.

A novel method for tinidazole detection using Mn-modified CdSe/CdS quantum dots as a luminescent probe.

A new method for the determination of tinidazole based on the fluorescence quenching of citrate-capped Mn-modified CdSe/CdS quantum dots was developed. In aqueous solution, the fluorescence of the quantum dots at 610 nm was quenched gradually with the increase of the concentration of tinidazole. Based on this, a simple, fast, low-cost and specific quantitative method for tinidazole detection was set up. Under optimal conditions, a good linearity was built between the fluorescence quenching of Mn-modified CdSe/CdS quantum dots and the concentration of tinidazole in the range of 4-400 microM with a correlation coefficient of 0.9998. The limit of detection (3sigma/K) was 0.4 microM. The proposed method was applied to the detections of tinidazole in tablets and injections with satisfactory results.

Tinidazole removal from aqueous solution by sonolysis in the presence of hydrogen peroxide.

Aqueous solutions of the tinidazole (TNZ) have been treated by applying the combination of ultrasound irradiation and H2O2. Based on the results, the maximum removal efficiency of 75% was achieved under the optimum operating conditions (pH 3, 120 kHz frequency, 333 mM/L of H2O2 and 150 min of operating time) while, under the same conditions the minimum removal efficiency was found to be 8.5 by ultrasound radiation in the absence of H2O2. The results also revealed that the degradation of TNZ was enhanced with decreasing both TNZ initial concentrations and pH. Furthermore, TNZ removal efficiency in the case of actual wastewater was less than of synthetic wastewater (75% and 68% of synthetic and actual, respectively). According to the chromatographic analyses, no harmful intermediate compounds were observed. The chemical oxygen demand analysis (65% reduction) confirmed our findings.

Micellar HPLC and derivative spectrophotometric methods for the simultaneous determination of fluconazole and tinidazole in pharmaceuticals and biological fluids.

Micellar high-performance liquid chromatography (HPLC) and first-derivative ultraviolet spectrophotometry were used to simultaneously determine fluconazole (FLZ) and tinidazole (TNZ) in combined pharmaceutical dosage forms. The derivative procedure is based on the linear relationship between the drug concentration and the first derivative amplitudes at 220 and 288 nm for FLZ and TNZ, respectively. The calibration graphs were linear in the range of 1.5-9.0 µg/mL for FLZ and 10.0-60.0 µg/mL for TNZ. Furthermore, an HPLC procedure with ultraviolet detection at 210 nm was developed. For the HPLC procedure, good chromatographic separation was achieved using an ODS C18 column (250 × 4.6 mm i.d.). The mobile phase containing 0.15M sodium dodecyl sulphate, 0.3% triethylamine and 12% n-propanol in 0.02M orthophosphoric acid at pH 5.5 was pumped at a flow rate of 1 mL/min. Indapamide was used as an internal standard. The method showed good linearity over the concentration ranges of 1.5-30.0 and 10.0-200.0 µg/mL, with limits of detection of 0.36 and 2.70 µg/mL and limits of quantification of 1.1 and 8.2 µg/mL for FLZ and TNZ, respectively. The suggested methods were successfully applied for the simultaneous analysis of the drugs in their laboratory prepared mixture, co-formulated tablet and single dosage forms. Moreover the second method was also extended to the determination of the drugs in biological fluids.

RP-HPLC/pre-column derivatization for analysis of omeprazole, tinidazole, doxycycline and clarithromycin.

A validated, reliable and accurate reversed-phase high performance liquid chromatographic method using pre-column derivatization was adopted for the simultaneous determination of two ternary mixtures containing omeprazole, tinidazole and doxycycline hyclate or clarithromycin. Separation was achieved on a C18 column, through a gradient elution system using acetonitrile-methanol-water adjusted to pH = 6.60. Drugs were detected at 277 nm over concentration ranges of 1-112, 5-125, 2.5-550 and 2.5-100 µg/mL for omeprazole, tinidazole, doxycycline hyclate and clarithromycin, respectively. This is the first method that has isolated and identified clarithromycin derivative by infrared and mass spectroscopy. This method is the first study for the simultaneous determination of omeprazole, tinidazole, doxycycline hyclate and clarithromycin in combined mixtures and pharmaceutical formulations.

Comparative study of novel spectrophotometric methods manipulating ratio spectra: an application on pharmaceutical ternary mixture of omeprazole, tinidazole and clarithromycin.

Three simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra are developed for simultaneous determination of omeprazole (OM), tinidazole (TN) and clarithromycin (CL) in tablets. Method A, is an extended ratio subtraction one (EXRSM). Method B is a ratio difference spectrophotometric one (RDSM), while method C is mean centering of ratio spectra (MCR). The calibration curves are linear over the concentration range of 1-20 µg/mL, 10-60 µg/mL and 0.25-1.0 mg/mL for OM, TN and CL, respectively. The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures of the three drugs and their combined dosage form. Standard deviation values are less than 1.5 in the assay of raw materials and tablets. The three methods are validated as per ICH guidelines and accuracy, precision, repeatability and robustness are found to be within the acceptable limits.

Simultaneous quantification of metronidazole, tinidazole, ornidazole and morinidazole in human saliva.

The aim of this study was to develop a rapid and sensitive method for the simultaneous quantification of metronidazole (MEZ), tinidazole (TNZ), ornidazole (ONZ) and morinidazole (MNZ) in human saliva. A reversed-phase high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection at 318 nm was carried out on a C18 column, using a mixture of potassium dihydrogen phosphate buffer, acetonitrile, and methanol (55:15:30, v/v/v) as a mobile phase with a flow rate of 1.0 ml/min. The saliva samples (100 µl) were firstly deproteinized by precipitation with methanol (400 µl), after which they were centrifuged and the supernatants were directly injected into the HPLC system. This method produced linear responses in the concentration ranges of 25.2-5040.0, 23.9-4790.0, 25.4-5080.0, 25.0-5000.0 ng/ml with detection limits of 6.0, 17.6, 10.0 and 11.3 ng/ml for MEZ, TNZ, ONZ and MNZ (S/N=3), respectively. The methods were validated in terms of intra- and inter-batch precision (within 7.3% and 9.1%, respectively), accuracy, linearity, recovery and stability. The study proved that HPLC is both sensitive and selective for the simultaneous quantification of MEZ, TNZ, ONZ and MNZ in human saliva using a single mobile phase.

[Far-IR and THz absorption spectra studies of metronidazole, tinidazole and ornidazole].

Metronidazole, tinidazole and ornidazole are 5-nitro-imidazole medicines used particularly for anaerobic bacteria and protozoa infections. The present paper reports that terahertz time-domain spectroscopy (THz-TDS) and Fourier transform infrared spectroscopy (Far-FTIR) were used to measure the fingerprint spectra of metronidazole, tinidazole and ornidazole in the frequency range of 0.9 - 19.5 THz under the room temperature. In addition, THz-TDS was also used to measure the absorption spectra of pure tinidazole and tinidazole tablets from different manufactures between 0.2 and 2.2 THz. In parallel with the experimental study, the cross correlation analysis was applied to compare the array of correlation coefficients between pure tinidazole and different tinidazole tablets. Results show that the method is rapid, simple and accurate to identify their effective chemical compositions and stability when the FTIR and THz spectra data combine with the array of correlation coefficient. Our research provides a visual approach to the standardization and modernization of the quality control in the production and sale of such drugs.

Extractional spectrophotometric analysis of metronidazole, tinidazole, ornidazole and secnidazole bases through acid-dye complexation using bromothymol blue dye.

An easy, precise and valid extractional-spectrophotometric technique is described for the assessment of metronidazole (MNZ), tinidazole (TNZ), ornidazole (ONZ) and secnidazole (SNZ) in pure state and in their pharmaceutical formulations. The technique includes first the reduction of above cited drugs using HCl and zinc powder, then the formation of intense yellow colored ion-association complex species (1:3 drug/dye) using bromothymol blue (BTB) in a buffered aqueous acidic medium at pH 3-3.50. The colored products are extracted into dichloromethane and quantitatively determined at 416-420 nm. The experimental operating factors influencing the ion-pairs development were studied and optimized to obtain the maximum color intensity. The Beer plots are obeyed in the concentration ranges 2.50-22.50, 2.50-30, 7.50-35 and 5-30 µgml-1 for MNZ, TNZ, ONZ and SNZ, respectively, with correlation coefficients not less than 0.9995. The proposed technique is recommended for the routine quality control analysis of the investigated drugs in commercial tablets with no observed interference from common pharmaceutical adjuvants. Results of such analysis were statistically validated and through recovery studies, showing excellent agreement with those achieved by the reported techniques.

[Determination of nitroimidazoles in oral hygiene by ultra-performance liquid chromatography-tandem mass spectrometry].

A method for the simultaneous determination of metronidazole, tinidazole, ornidazole, ronidazole and dimetridazole in oral hygiene by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed. The sample was diluted with 0.1% formic acid/acetonitrile (95:5, v/v), then centrifuged and filtered with a membrane. The separation was carried out on a Cloversil C18 column (100 mm x 2.1 mm, 3.5 microm) with the gradient elution of 0.1% formic acid and acetonitrile as the mobile phases. The analytes were determined by UPLC-MS/MS and quantified by external standard method. The calibration curves showed good linearity in the range of 1.0-60.0 microg/L with r > or = 0.9992. The recoveries were 91.5%-108% at the three spiked levels of 10.0, 20.0 and 100 mg/kg, and the relative standard deviations were 1.14%-5.22%. This method is easy, sensitive and suitable for the determination of nitroimidazoles in oral hygiene.

Dried blood spot assay for estimation of metronidazole concentrations in rats and its application in single animal drug pharmacokinetic study.

An HPLC-UV-dried blood spot (DBS) method for the estimation of metronidazole (MTZ) in rat whole blood is reported. Method employs Ahlstrom 226 sample collection paper and DBS samples were prepared by spotting with 30 µl of whole blood (spiked calibration standards/quality control samples/in vivo study samples). A 6mm disc was punched from each DBS and extraction was carried out using water containing the internal standard (tinidazole). The calibration for MTZ was linear over 2.5-50 µg/ml concentration range. Accuracy (% bias) and precision (expressed as % Coefficient of variation) values for within and between day were <20% at the lower level quality control sample (LQC) and <15% at all other concentrations tested. The limit of quantification (LOQ) of the method was 2.5 µg/ml. The validated method was applied for the analysis of in vivo pharmacokinetic (PK) study samples after intravenous administration of MTZ to a rat. Whole blood PK parameters observed in this study were in compliance with literature based PK parameters. The DBS sampling approach was found to be useful in a single animal pharmacokinetic study.

A new approach to the spectrophotometric determination of metronidazole and tinidazole using p-dimethylaminobenzaldehyde.

A new approach to the spectrophotometric determination of metronidazole (MZ) and tinidazole (TZ) has been developed. The procedure involves coupling of diazotized nitroimidazoles with p-dimethylaminobenzaldehyde (DMAB) to form a greenish-yellow solution. Optimal temperature and time were 0 degrees C (iced) and 3 minutes for diazotization and 30 degrees C and 2 minutes for coupling for both MZ and TZ. Coloured adducts of MZ and TZ showed shoulders at 406 nm and 404 nm, respectively, which were selected as analytical wavelengths. The reaction with p-DMAB occurred in a 1:1 mole ratio. Beer's law was obeyed within the 4.8-76.8 microg mL(-1) concentration range with low limits of detection. The azo adducts were stable for over a week. Molar absorptivities were 1.10 x 10(3) (MZ) and 1.30 x 10(3) L mol(-1) cm(-1) (TZ). Overall recoveries of MZ and TZ from quality control samples were 103.2 + or - 1.3 and 101.9 + or - 1.3% over three days. There was no interference from commonly utilized tablet excipients. No significant difference was obtained between the results of the new method and the BP titrimetric procedures. The azo approach using the p-dimethylaminobenzaldehyde procedure described in this paper is simple, fast, accurate and precise. It is the first application of DMAB as a coupling component in the diazo coupling reaction.

Simple HPLC method for simultaneous estimation of fluconazole and tinidazole in combined dose tablet.

A rapid and sensitive reversed-phase high-performance liquid chromatographic method is developed for simultaneous estimation of fluconazole, an orally active triazole anti-fungal agent, and tinidazole, which belongs to the group of 5-nitroimidazoles in combined dose tablet. Chromatographic separation was on an ODS Hypersil C(18) column using 0.05 M potassium dihydrogen phosphate buffer (pH 3.25, adjusted with orthophosphoric acid) and acetonitrile (82:18, v/v) as the mobile phase at a flow rate of 1.5 mL/min with detection at 210 nm. The asymmetry factors are 1.36 +/- 0.04 for fluconazole and 1.26 +/- 0.07 for tinidazole with a total run time of less than 7 min. The calibration curves were linear in the range 6-14 microg/mL for fluconazole and 80-190 microg/mL for tinidazole. The method was validated with respect to linearity, precision, accuracy, and specificity. The mean recovery for fluconazole and tinidazole is 99.65 +/- 0.84 and 99.34 +/- 0.70, respectively. The utility of the procedure is verified by its application to the market formulation that was subjected to various stressed conditions. Two potential degradation products of tinidazole on exposure to alkaline stressed condition are well-resolved. The method separated the two target drugs and degradation products well. No chromatographic interference is observed.

Gamma irradiation of pharmaceutical compounds, nitroimidazoles, as a new alternative for water treatment.

The main objectives of this study were: (1) to investigate the decomposition and mineralization of nitroimidazoles (Metronidazole [MNZ], Dimetridazole [DMZ], and Tinidazole [TNZ]) in waste and drinking water using gamma irradiation; (2) to study the decomposition kinetics of these nitroimidazoles; and (3) to evaluate the efficacy of nitroimidazole removal using radical promoters and scavengers. The results obtained showed that nitroimidazole concentrations decreased with increasing absorbed dose. No differences in irradiation kinetic constant were detected for any nitroimidazole studied (0.0014-0.0017 Gy(-1)). The decomposition yield was higher under acidic conditions than in neutral and alkaline media. Results obtained showed that, at appropriate concentrations, H(2)O(2) accelerates MNZ degradation by generating additional HO(); however, when the dosage of H(2)O(2) exceeds the optimal concentration, the efficacy of MNZ degradation is reduced. The presence of t-BuOH (HO() radical scavenger) and thiourea (HO(), H() and e(aq)(-) scavenger) reduced the MNZ irradiation rate, indicating that degradation of this pollutant can take place via two pathways: oxidation by HO() radicals and reduction by e(aq)(-) and H(). MNZ removal rate was slightly lower in subterranean and surface waters than in ultrapure water and was markedly lower in wastewater. Regardless of the water chemical composition, MNZ gamma irradiation can achieve i) a decrease in the concentration of dissolved organic carbon, and ii) a reduction in the toxicity of the system with higher gamma absorbed dose.

Simultaneous determination of nitroimidazole residues in honey samples by high-performance liquid chromatography with ultraviolet detection.

A rapid and sensitive high-performance liquid chromatography (LC) method was developed for the simultaneous determination of metronidazole (MNZ), dimetridazole (DMZ), ronidazole (RNZ), tinidazole (TNZ), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI) in honey. After extraction with ethyl acetate and evaporation, the residue containing the nitroimidazoles was dissolved in ethyl acetate-hexane and subjected to solid-phase extraction cleanup by amine extraction columns. The effluent was evaporated to dryness, and residues were dissolved and determined by LC with an ultraviolet detector set at 315 nm. The limits of detection were 1.0-2.0 ng/g for MNZ, DMZ, RNZ, TNZ, and HMMNI in honey. Average recoveries ranged from 71.5-101.4% in honey fortified at 10, 20, 50, and 100 ng/g. The method was validated for the analysis of real honey samples.