Therapeutic isoniazid monitoring using a simple high-performance liquid chromatographic method with ultraviolet detection

A Simple and Sensitive UPLC–UV Method for Simultaneous Determination of Isoniazid, Pyrazinamide, and Rifampicin in Human Plasma and Its Application in Therapeutic Drug Monitoring

As the first-line clinical drugs for tuberculosis (TB), isoniazid (INH), pyrazinamide (PZA), and rifampicin (RMP) are playing important roles for preventing the rapid spread of TB. Precise quantification of these drugs in biological samples is crucial to evaluate or improve the efficacy of advanced TB drug delivery systems, which are designed for reducing drug resistance, minimizing side effects, etc. Herein, a simple and sensitive method based on UPLC–UV was established and investigated for simultaneous quantification of PZA, INH, and RMP in human plasma and was applied to anti-TB drug therapeutic drug monitoring. The analytes were implemented on an HSS T3 C18 column at 40°C. The separation was performed with a gradient elution with methanol–acetonitrile–water (3:3:94) at 0.1 ml/min. The analysis only involved plasma with a small volume of 100 µL and a rapid one-step protein precipitation with methanol–acetonitrile (1:1). The results showed that the calibration curves for INH, PZA, and RMP were linear in a range of 0.5–20 μg/ml, 5–60 μg/ml, and 5–60 μg/ml, respectively. The intra- and inter-day precisions were both smaller than 15%, and the lower limit of quantitation (LLOQ) was identifiable and reproducible at 0.5 μg/ml for INH and 5 μg/ml for both PZA and RMP, respectively. The target drugs in plasma were stable after 21 days of storage at −80°C. The results indicated that our developed method is suitable for the simultaneous monitoring of INH, PZA, and RMP in human plasma.

Real-life isoniazid and rifampicin plasma concentrations in children: a tool for therapeutic drug monitoring of tuberculosis

Background

Low plasma levels of first-line antitubercular drugs can be counted among the main causes of poor response to antitubercular therapy, and therapeutic drug monitoring has been proposed as a method to promote tailored treatments for both child and adult patients. The main aim of the study was to evaluate serum concentrations of isoniazid (INH) and rifampicin (RIF) and to investigate reasons for sub-therapeutic plasma concentrations in order to fix dosages.

Methods

Children with TB were prospectively enrolled from January to August 2019. Two venous blood samples were collected (the first at least 15 days after the beginning of antitubercular treatment, and the second between 1 and 8 weeks later). Plasma concentrations were determined by a validated high-performance liquid chromatography method.

Results

In all, 45 children were included. Seventy blood samples for INH plasma concentration were collected between 120 and 240 min after drug intake. Adjusting for dose (mg/kg/day) and time of INH administration, when considering three different age groups (≤ 2 years, 2–12 years, > 12 years), a statistically significant lower INH plasma concentration was observed in younger children compared to the older age groups in the multivariate analysis (p < 0.001 and p < 0.001). A total of 68 blood samples were evaluated for RIF concentrations. Both for INH and RIF a statistically significant lower plasma concentration was also observed in adolescents (p < 0.001). Fifteen children (15/45, 33%) presented drug concentrations under the referral therapeutic range.

Conclusions

Based on our findings, monitoring patients’ drug plasma concentrations in children under 2 years of age and in adolescents can make treatment more patient-tailored.

Simultaneous determination of first-line anti-tuberculosis drugs and one metabolite of isoniazid by liquid chromatography/tandem mass spectrometry in patients with human immunodeficiency virus-tuberculosis coinfection

The incidence rate of tuberculosis (TB) in patients with human immunodeficiency virus (HIV) infection is 26 times higher than that in other patients. Patients with both infections require long-term combination therapy, which increases therapy complexity and might lead to serious adverse reactions and drug-drug interactions. To optimize therapy for patients with HIV and TB coinfection, we developed an ultra-high-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS) method to simultaneously quantify four anti-tuberculosis drugs and one isoniazid (INH) metabolite. Blood samples (n = 32) from 16 patients with HIV and TB coinfection were collected. Plasma protein precipitation with acetonitrile was followed by a hydrazine reaction between INH and cinnamaldehyde (CA) to produce phenylhydrazone (CA-INH) and dilution with heptafluorobutyric acid. The separation was performed on an Acquity UHPLC HSS T3 1.8 μm column (2.1 × 100 mm, Waters) with a mobile phase consisting of 10 mmol/L ammonium formate (pH = 4) in water (solvent A) and 0.1 % formic acid in methanol (solvent B) in a gradient elution. The compounds were detected using a positive multiple reaction monitoring model. INH, acetyl-INH (AC-INH), rifampicin (RIF), ethambutol (EMB), and pyrazinamide (PZA) showed good linear relationships in their quantitative ranges, with lower limits of quantification of 48, 192, 200, 96, and 480 ng/mL, respectively. The inter- and intraday precision was within 15 %, and the accuracy was between 85 % and 115 %. The mean plasma concentrations of INH, AC-INH, RIF, EMB, and PZA in patients were 1990.23 (24–16 600), 863.06 (96–2880), 3507.05 (229–9800), 808.10 (149–2130), and 18 838.33 (240–34 800) ng/mL, respectively. The plasma concentrations detected in the 16 patients were lower than the targeted concentrations in HIV-negative TB patients. In summary, we developed a simple UHPLC-MS/MS method for simultaneous quantification of first-line TB drugs, and successfully applied it for therapeutic drug monitoring in patients with HIV and TB coinfection. This method will facilitate monitoring of TB drugs in the future.

A simple signal-on strategy for fluorescent detection of tuberculostatic drug isoniazid based on Ag clusters-MnO2 sheets nanoplatform

As a first-line tuberculostatic drug, isoniazid (INH) plays effective and irreplaceable role in prevention and treatment of tuberculosis. In this work, a rapid and simple signal-on fluorescence approach is established for INH assay by employing a platform composed of silver nanoclusters (AgNCs) and MnO₂ nanosheets. In the proposed sensing system, strong red fluorescence of poly (methacrylic acid)-stabilized AgNCs can be greatly quenched after they attach to the surfaces of MnO₂ nanosheets. With the addition of INH, MnO₂ nanosheets are reduced to Mn²⁺ and subsequently release the AgNCs, which leads to obvious fluorescence recovery again. Based on this mechanism, highly sensitive detection of INH in the range of 0.8-200 μM is realized (detection limit: 476 nM). The present strategy shows remarkable advantages including simplicity, rapidness, high sensitivity and wide detectable range. This method is also practical and comparable to high-performance liquid chromatography, which can be applied to detect INH in human urine and serum samples as well as pharmaceutical products.

Isoniazid: A Review of Characteristics, Properties and Analytical Methods

Isoniazid is a synthetic antimicrobial and one of the most important first-line drugs used in the treatment of tuberculosis. Since it was introduced in the therapy in 1952, the drug remains at the front line of the antituberculosis treatment mainly due to its potency and high selectivity against Mycobacterium tuberculosis. Pharmaceutical analysis and therapeutic drug monitoring of isoniazid in both, pharmaceuticals and biological samples, plays an important role to comprehend aspects regarding to bioavailability, bioequivalence and therapeutic monitoring during patients following-up. In the last case, validated and simple methods are extremely useful for Public Healthy in order to guarantee the drug efficacy, safety and reduce the tuberculosis resistance. Among the available analytical tools, HPLC-based methods coupled to ultraviolet or mass spectroscopy are the most widely used techniques to quantify isoniazid. Therefore, this review highlights the main analytical methods reported in the literature for determination of isoniazid focusing in HPLC-based methods.

Prevention of isoniazid toxicity by NAT2 genotyping in Senegalese tuberculosis patients

Isoniazid (INH), recommended by WHO (World Health Organization) in the treatment of tuberculosis (TB), is metabolized primarily by the genetically polymorphic N-acetyltransferase 2 (NAT2) enzyme. The human population is divided into three different phenotypic groups according to acetylation rate: slow, intermediate, and fast acetylators. The objective of this study was to explore the relationship between NAT2 genotypes and the serum concentrations of INH. Blood samples from 96 patients with TB were taken for the analysis. NAT2 polymorphisms on coding region were examined by polymerase chain reaction (PCR) direct sequencing; the acetylation status was obtained by measuring isoniazid (INH) and its metabolite, acetylisoniazid (AcINH) in plasma was obtained by using the liquid chromatography coupled to mass spectrometry. TB patients were distributed into two groups of fast and slow acetylators according to the acetylation index calculated based on the plasma concentration of INH in the 3rd hour (T3) after an oral dose. Our PCR analysis identified several alleles, where NAT2*4, NAT2*5A, NAT2*6A, and NAT2*13A were the most important. The concentrations of INH varied between 1.10 mg/L and 13.10 mg/L at the 3rd hour and between 0.1 and 9.5 mg/L at the 6th hour. The use of the acetylating index I₃ allowed the classification of tested patients into two phenotypic groups: slow acetylators (44.3% of TB patients), and rapid acetylators (55.7%). Patient’s acetylation profile provides valuable information on their therapeutic, pharmacological, and toxicological responses.

Rifampicin and isoniazid plasma concentrations in relation to adverse reactions in tuberculosis patients: a retrospective analysis

OBJECTIVE

High concentrations of antituberculosis (anti-TB) drugs can be associated with many adverse drug reactions (ADRs). The objective of this study was to examine the plasma concentrations of rifampicin (RMP) and isoniazid (INH) in patients with and without ADRs.

METHODS

Concentration monitoring data of patients treated with anti-TB drugs were retrospectively analyzed from 2009 to 2011. RMP and INH plasma concentrations were measured 2 and 3 h after drug administration respectively using high-performance liquid chromatography.

RESULTS

A total of 54 out of 120 patients have experienced ADRs to anti-TB drugs. The median concentrations [interquartile range (IQR)] obtained in patients with and without ADRs were 6.7 mg/l (3.7-9.9) and 5.6 mg/l (2.9-8.6) (p = 0.56) for RMP and 4.3 mg/l (2.3-5.3) and 3.1 mg/l (1.7-4.8) (p = 0.04) for INH, respectively. Related median doses (IQR) were 8.7 mg/kg (8.0-10.0) and 8.6 mg/kg (6.5-9.9) (p = 0.42) for RMP and 4.8 mg/kg (4.3-5.0) and 4.0 mg/kg (2.8-5) (p < 0.01) for INH, respectively. Concentrations above the expected range in patients with and without ADRs were not reached for RMP, but were 76% and 65% for INH, respectively. Correlation between concentrations and doses has not been established for RMP or INH. In addition, high INH concentrations showed no association with sex, age, liver injury or renal or diabetes.

CONCLUSIONS

High INH concentrations were common in patients with and without ADRs whereas RMP concentrations were low or within the normal range in most patients. Further studies are required to assess the association between high INH concentrations and the occurrence of ADRs.

Potassium permanganate-acridine yellow chemiluminescence system for the determination of fluvoxamine, isoniazid and ceftriaxone

Based on the oxidation of acridine yellow by permanganate in basic medium, a new chemiluminescence system was developed for the sensitive determination of some important drugs. The remarkable inhibiting effect of fluvoxamine, ceftriaxone and isoniazid on this reaction was applied to their detection. A possible mechanism was proposed for this system based on chemiluminescence emission wavelengths and experimental observations. Under optimum conditions, calibration graphs were obtained for 1 × 10(-9) to 1 × 10(-6) mol/L of fluvoxamine; 2 × 10(-8) to 8 × 10(-6) mol/L of ceftriaxone and 5 × 10(-8) to 4 × 10(-5) mol/L of isoniazid. This proposed method was satisfactorily used in the determination of these drugs in pharmaceutical samples and human urine and serum.

Correlation of N-acetyltransferase 2 genotype with isoniazid acetylation in Polish tuberculosis patients

Isoniazid (INH), a key agent in the treatment of tuberculosis (TB), is metabolized primarily by the genetically polymorphic N-acetyltransferase 2 (NAT2) enzyme. Patients treated with INH can be classified as fast, intermediate, and slow acetylators. The objective of this study was to explore the relationship between NAT2 genotypes and the serum concentrations of INH. Blood samples from 130 patients were taken for the analysis, and plasma INH concentrations were determined by using the high-performance liquid chromatography (HPLC) technology. Acetylation genotype was determined on genomic DNA by using an allele-specific polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Once the NAT2 genotypes were established, patients were classified into three categories: fast, intermediate, and slow acetylators. Of the 130 patients studied, 84 (64.6%) were slow, 39 (30%) were intermediate, and 7 (5.4%) were fast acetylators. Analysis of INH concentrations in the blood of patients receiving the approximate doses of the drug revealed that, at the time intervals examined, the average concentration of INH was 2- to 7-fold higher among slow acetylators compared to fast and intermediate acetylators.

CONCLUSION

Determining mutations in the NAT2 gene enabled the identification of the INH acetylation type in patients and the genotyping results were consistent with the phenotype determined by methods of measurement of drug bioavailability.

Simultaneous determination of first-line anti-tuberculosis drugs and their major metabolic ratios by liquid chromatography/tandem mass spectrometry

Monitoring of anti-tuberculosis drug concentrations and dose adjustment can be helpful in cases that show poor response to treatment. Here, we describe a method that can rapidly and simultaneously measure the blood concentrations of four anti-tuberculosis drugs (isoniazid, rifampicin, pyrazinamide, and ethambutol) and two major metabolic ratios (acetylisoniazid/isoniazid and 25-desacetylrifampicin/rifampicin) using high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). A C18 reversed-phase column and gradients of methanol in 0.3% formic acid and water were used for HPLC separation. The drug concentrations were determined by multiple reaction monitoring in positive ion mode and the assay performance was evaluated. We determined peak concentration ranges for each drug and acetylisoniazid/isoniazid and 25-desacetylrifampicin/rifampicin ratios by analyzing 2-h post-dose samples in patients treated with standard dosing as a first-line treatment. The preparation of 20 samples including two steps of deproteinization with 50% and 100% methanol was performed within 20 min and chromatographic separation was achieved within 4 min/sample. Interassay calibration variability data obtained over concentrations of 0-8 microg/mL for isoniazid and ethambutol and 0-80 microg/mL for rifampicin and pyrazinamide showed a linear and reproducible curve. Within-run and between-run imprecision (CVs) were 1.9-5.5% and 3.5-10.5% and the lower limits of detection and quantification were 0.01-0.5 microg/mL and 0.05-1.0 microg/mL, respectively. The isoniazid concentration was found to be inversely correlated to the acetylisoniazid/isoniazid ratio (R=-0.739, P<0.001). The devised method allows for the simple, rapid, sensitive and reproducible quantification of isoniazid, rifampicin, pyrazinamide, ethambutol and their two metabolic ratios and should be helpful for therapeutic drug monitoring in tuberculosis patients.

Quantification of isoniazid and acetylisoniazid in rat plasma and alveolar macrophages by liquid chromatography-tandem mass spectrometry with on-line extraction

To evaluate if pulmonary delivery of microparticles loaded with a prodrug of isoniazid (INH), isoniazid methanesulfonate (INHMS), can target alveolar macrophages (AM) and reduce metabolism of INH, an HPLC-MS/MS assay with automated online extraction for quantification of INH and its metabolite acetylisoniazid (AcINH) in plasma and AMs was developed and validated. Reproducibility in rat plasma and homogenate of a rat AM cell line, NR8383, for INH and AcINH showed excellent precision and accuracy with calibration curves exhibiting linearity within a range of 1-250ng/ml of INH and 0.05-50ng/ml of AcINH (r(2)>0.99). The validated methods were successfully applied to pharmacokinetic study of INHMS-loaded microparticles in rats, demonstrating efficient targeting of AMs and reduction of INH metabolism.

Microparticle-based lung delivery of INH decreases INH metabolism and targets alveolar macrophages

Microparticles prepared by the precipitation with a compressed antisolvent (PCA) process were evaluated for their potential in targeting an ionizable prodrug of isoniazid (INH), isoniazid methanesulfonate (INHMS), for sustained delivery of INH to alveolar macrophages (AMs). The charged prodrug was ion-paired with two different hydrophobic cations (tetrapentylammonium (TPA)- and tetraheptylammonium (THA)-bromide), and loaded separately into the poly(l-lactide) (PLA) microparticles. The drug/polymer particles were spherical in shape and between 1 and 3 mum in diameter. The choice of hydrophobic cations did not affect drug incorporation efficiencies or the release kinetics of INH from the microparticles. Using a sensitive liquid chromatographic tandem mass spectrometric (LC-MS/MS) assay developed for INH, high level of INH was detected in NR8383, a rat AM cell line, following exposure of these cells to drug-loaded microparticles. To confirm the microparticles can target AMs in vivo, we compared the INH levels in lavaged bronchoalveolar macrophages by LC-MS/MS after the Sprague-Dawley rats were administered either INHMS in PLA microparticles by intra-tracheal instillation or INH solution by gavage or intra-tracheal instillation. As expected, only microparticles provided sustained and targeted delivery of INH to AMs. Most importantly, this method of delivery led to substantial reduction in the blood levels of acetylisoniazid (AcINH), a major and potential toxic metabolite of INH.

A liquid chromatography/tandem mass spectrometry method for the simultaneous quantification of isoniazid and ethambutol in human plasma

Isoniazid and ethambutol are commonly used in various combination treatments for tuberculosis, and for this reason a rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated for simultaneous quantification of these two drugs in human plasma. After a simple protein precipitation using methanol, the analytes and the internal standard metformin were chromatographed on a C18 column and detected by MS/MS. An atmospheric pressure chemical ionization interface was chosen to reduce ion suppression from sample matrix components and provide high sensitivity. The LC retention times for isoniazid and ethambutol were 2.46 and 2.27 min, respectively. The method was linear in the concentration range of 10.0-5000 ng/mL for each analyte using 100 microL plasma. The intra- and inter-day precisions, expressed as the relative standard deviation (RSD), were less than 5.7 and 6.4%, determined from QC samples for isoniazid and ethambutol, and the accuracies were within +/-2.1% and +/-4.5% in terms of relative error, respectively. The method was successfully employed in a pharmacokinetic study after oral administration of a multicomponent formulation containing 150 mg isoniazid, 500 mg ethambutol, 150 mg rifampicin and 250 mg pyrazinamide.

Direct injection of solid-phase extraction eluents onto silica columns for the analysis of polar compounds isoniazid and cetirizine in plasma using hydrophilic interaction chromatography with tandem mass spectrometry

Isoniazid and cetirizine do not retain well on reversed-phase columns due to their high polarity. Silica columns, when operated under hydrophilic interaction conditions, do provide excellent retention of these compounds. We have developed simple and proof of concept analytical methods for the analysis of isoniazid and cetirizine in animal and human plasma, respectively. Both methods employed the approach of direct injection of solid-phase extraction (SPE) organic eluents onto silica columns for analysis, thus eliminating evaporation and reconstitution steps that are typically needed for reversed-phase liquid chromatographic analysis. Isoniazid was extracted from animal plasma samples using a Waters Oasis HLB 96-well plate and then eluted with acetonitrile, while cetirizine was extracted from human plasma with a Waters MCX mu-Elute plate and then eluted with acetonitrile containing 5% concentrated ammonium hydroxide. The direct injection of the SPE eluent onto the analytical column was necessary since significant loss of isoniazid was found during the evaporation and reconstitution steps. The method for isoniazid also enabled ultra-fast analysis due to the relatively low back-pressure exhibited by silica columns even under high flow conditions. Both methods show good linearity, accuracy and precision covering the range of 10-2000 ng/mL of isoniazid, and 1-1000 ng/mL of cetirizine in plasma. Substantial time savings were realized as a result of both the elimination of the evaporation and reconstitution steps and the fast chromatographic analysis.