Isoniazid Levels Research Articles

Sex-dependent variability of isoniazid and rifampicin serum levels in patients with tuberculosis.

Drug-sensitive TB (DS-TB) is treated with isoniazid, rifampicin, ethambutol, and pyrazinamide. Factors like fast-metabolizing enzymes, malabsorption, and drug interactions can influence serum drug levels. Current TB treatment guidelines recommend weight-adapted dosing without considering sex differences. This study examines drug levels of isoniazid and rifampicin in TB patients treated between 2019 and 2023 at our center focusing on sex-specific aspects. Patients diagnosed with TB and available serum levels of isoniazid or rifampicin between 2019 and 2023 were retrospectively identified. Serum levels were measured using liquid chromatography-mass spectrometry and high-performance liquid chromatography. Patients were stratified by sex and a linear regression mixed effect model was used to assess predictors for different serum levels. The study included 281 single therapeutic drug monitoring (TDM) measurements from 59 patients (28 women, 47.5%). For isoniazid, no sex-specific differences in serum drug levels were identified. On the other hand, female sex was a significant predictor of higher rifampicin plasma levels (coefficient 4.16, 95% CI 0.74-7.59, p = 0.009). Only 38.2% of rifampicin serum level measurements in male patients were within target range, the majority (40/68, 58.8%) were below range and only 2 (2.9%) TDM-levels were above range. Women displayed higher overall rifampicin serum levels than men (median 13.7mg/l vs. 7.1mg/l, p = 0.04), although weight adjusted doses were not significantly different (median 10.0mg/kg vs. 9.8mg/kg p = 0.56). Adverse effects were noted in 42.9% (42/98) of measurements in women and 29.5% (54/183) of measurements in men (p = 0.03). Rifampicin levels were significantly lower in men compared to women, despite weight-adjusted dosing. Clinicians should consider TDM and potential sex differences when treating patients with TB.

Therapeutic Drug Monitoring of Isoniazid Among Newly Diagnosed Pulmonary Tuberculosis Patients

Introduction: Tuberculosis has a higher incidence in lower income countries. Positive treatment outcomes may be fewer due to comorbidities like diabetes mellitus and immunosuppressive illnesses. The Global Tuberculosis Network working under the umbrella of World Health Organization has composed different committees. The TB Pharmacology Committee has given the concept of precision medicine and treatment based on drug susceptibility testing. Achievement of optimum plasma levels of anti-tuberculous drugs by therapeutic drug monitoring (TDM) is imperative and being emphasized to achieve a TB cure. Aims and Objectives: To determine the levels of INH in low responders to ATT have lower plasma levels of Isoniazid. Place and Duration of study: University of Health Sciences and Gulab Devi Chest Hospital, Lahore, for 1 year from August 2017- July 2018. Material and Methods: A first dose therapeutic drug monitoring (TDM) of isoniazid (INH) was planned in 25 newly enrolled sputum positive tuberculous patients at Gulab-Devi Hospital. The work was approved by Ethical Review Committee. Fixed dose combination (FDC) of anti-tuberculous drugs was given under direct observation and blood samples were withdrawn at two hours (C2h) and six hours (C6h) on days one, 14 and 56th of drug therapy. Samples of sputum for acid fast bacilli (AFB) were also taken during blood sampling. Method development and validation of isoniazid estimation by high-performance liquid chromatography was carried out. Plasma INH concentration in test samples was measured with Shimadzu Chromatographic System, Japan. Data was entered and analyzed using SPSS version 20. A p value ? 0.05 was taken as statistically significant. Results: Among 25 patients enrolled to the current study, the mean plasma levels of isoniazid were 1.29±0.79 µg / ml and 0.56±0.43 µg / ml at two hours and six hours respectively throughout the research duration. Most of the patients had lesser plasma INH levels than the target ranges (< 3µg / ml). Sputum for acid fast bacilli was found 100% positive on day one and 14 however sputum conversion was 56% after four weeks drug therapy. Conclusion: An early TDM monitoring has revealed low plasma INH concentration. Correction of dose to achieve expected plasma INH level will have promising effect on sputum culture conversion. It will minimize the total statewide burden of slow responders and tuberculosis resistant cases.

A Tröger's base-linked aluminium phthalocyanine polymer for discriminative electrochemical sensing of the antibiotic isoniazid.

Isoniazid is a first-line drug used to treat tuberculosis. However, its excessive use can lead to serious adverse effects. Thus, strict monitoring of the isoniazid levels in medications and human systems is required. In this study, a new polymer (AlPc-TB POP) containing a metal phthalocyanine and Tröger's base was synthesized and explored as an electrocatalyst for the oxidation of isoniazid. The results indicated that the polymer is an excellent electron-transfer medium for isoniazid oxidation. The AlPc-TB POP-based sensor quantified isoniazid in the linear range of 0.1-130 μM, with a detection limit of 0.0185 μM. The response of the developed sensor to isoniazid was reproducible and stable. Furthermore, this method can accurately determine isoniazid levels by ignoring the influence of common interfering species in tablets and biological samples. This study contributes to the development of nitrogen-rich porous organic polymers and offers a novel strategy for addressing challenges in disease therapeutic efficacy and public safety monitoring.

Validation of Analytical Method LC MS/MS for Determination Isoniazid in Rats Serum

Determination of isoniazid concentration for therapeutic drug monitoring must produce valid values, so validation of the analytical method of LC-MS/MS needs to be carried out. This research aims to obtain valid method of LCMS/MS in order to determination isoniazid in rats serum. Sample preparation was carried out using the liquid-liquid extraction method using acetonitrile and methanol (2:1). The chromatography system was developed with a C18 column (ACQUITY UPLC® HSS T3 1.8 µm, 2.1 × 100 mm), the mobile phase was 70% acetonitrile with 0.1% formic acid (A), water with 0.1% formic acid (B), as well as methanol (C) with a flow rate of 0.3 mL/min, with gradient elution, detection in ESI+ mode with multiple reaction monitoring (MRM) at the transition 138 m/z → 121 m/z. The research results showed that the method was accurate with a % recovery of 96 - 113% and an RSD of 2.4 ± 0.9%. The precision value was obtained with an average RSD of 3.7 ± 2.4% for intra-day and 4.1 ± 2.3% for inter-day. Linearity showed good results with a correlation coefficient of 0.9956 in tests with 5 different concentrations. The LOQ and LOD values obtained from the linear regression equation were 0.1987 µg/mL and 0.0656 µg/mL respectively. The results showed that the LC-M/MS method was valid for determining isoniazid levels in rat serum

Effect of Metformin on Plasma Exposure of Rifampicin, Isoniazid, and Pyrazinamide in Patients on Treatment for Pulmonary Tuberculosis.

To evaluate the effect of metformin on the plasma levels of rifampicin, isoniazid, and pyrazinamide in patients with drug-sensitive pulmonary tuberculosis being treated with first-line antituberculosis treatment (ATT) and to assess the influence of gene polymorphisms on the metabolic pathway of metformin and plasma levels of antitubercular drugs. Nondiabetic adults aged 18-60 years with pulmonary tuberculosis were randomized to either the standard ATT (ATT group) or ATT plus metformin (METRIF group) groups in a phase IIB clinical trial. An intensive pharmacokinetic study with blood collection at 0 hour (predosing), followed by 1, 2, 4, 6, 8, and 12 hours after dosing was conducted during the first month of treatment in a subset of 60 study participants after a minimum of 14 doses. Plasma concentrations of rifampicin, isoniazid, pyrazinamide, and metformin were measured by high-performance liquid chromatography using validated methods, and pharmacokinetic parameters and OCT1 and MATE1 gene polymorphisms were compared between the groups. Significant increases in the clearance of rifampicin, isoniazid, and pyrazinamide were observed in patients in the METRIF group (n = 29) compared with those in the ATT group (n = 31). The AA genotypes of the single-nucleotide polymorphism of rs2289669 ( MATE1 ) in the METRIF group showed a significantly decreased area under the concentration-time curve to the last observation point and increased clearance of rifampicin. Metformin altered rifampicin and isoniazid plasma concentrations in patients receiving antituberculosis treatment for pulmonary tuberculosis with little effect on sputum conversion at the end of treatment. Studies with larger sample sizes are needed to understand host drug-drug interactions.

Association of Cytochrome P450 2E1 and N-Acetyltransferase 2 Genotypes with Serum Isoniazid Level and Anti-Tuberculosis Drug-Induced Hepatotoxicity: A Cross-Sectional Study.

Anti-tuberculosis drug-induced hepatotoxicity can result from genetic polymorphism of the isoniazid (INH) metabolizing enzyme. This study aimed to determine the effect of genetic polymorphism of N-acetyltransferase 2 (NAT2) and cytochrome P450 2E1 (CYP2E1) genes on serum isoniazid level and drug-induced hepatotoxicity. A cross-sectional study was conducted on 120 patients (with and without hepatotoxicity) with pulmonary tuberculosis from June 2019 to April 2022 in Tehran (Iran). High-performance liquid chromatography was used to measure the serum concentration of INH and acetylisoniazid (AcINH). NAT2 and CYP2E1 genotypes were determined using polymerase chain reaction and restriction fragment length polymorphism methods. Data were analyzed using SPSS software (version 22.0) with independent two-sample t test, Chi square test, or Fisher's exact test. P<0.05 was considered statistically significant. A total of 40 patients showed hepatotoxicity. The risk of anti-tuberculosis drug-induced hepatotoxicity was significantly higher in patients who are slow acetylator (SA) phenotype than in rapid or intermediate acetylator (P<0.001). NAT2*4/*4 genotypes were not found in patients with hepatotoxicity. The frequency of NAT2*5 and NAT2*6 haplotypes and serum INH concentration was significantly higher in patients with hepatotoxicity than in those without (P=0.003, P<0.001, and P<0.001, respectively). NAT2*4 haplotype was correlated with protection against hepatotoxicity. A combination of SA and CYP2E1 C1/C1 genotype was significantly associated with hepatotoxicity (P<0.001). Hepatotoxicity in Iranian patients with tuberculosis was confirmed due to the presence of NAT2 SA polymorphism. Determining NAT2 and CYP2E1 genotypes and/or INH concentration can be a valuable tool to identify patients susceptible to hepatotoxicity.

Isoniazid Resistance Level and Associated Resistance Conferring-mutations in Rifampicin Resistant Mycobacterium tuberculosis

Background: Multidrug resistant tuberculosis (MDR-TB) is a global public health problem causing treatment failure. Rifampicin (RIF) resistance has been used as a surrogate marker for MDR-TB diagnosis, but level of isoniazid (INH) resistance and associated resistance conferring mutations for INH in rifampicin-resistant TB cases are little known. Objective: The objective of this study was to determine level of isoniazid resistance and associated resistance conferring mutations in rifampicin resistant Mycobacterium tuberculosis (MTB) in sputum samples. Methods: A total 53 RIF resistant MTB isolates in sputum, detected by Xpert-MTB RIF assay were enrolled in the study. Culture positive samples were tested by BACTEC MGIT 960 system and level of isoniazid resistance was determined, defined as minimum inhibitory concentration of INH of &gt;0.4 µg/mL and 0.1-0.4 µg/mL as high level and low level INH resistance respectively. Distribution of mutation in katG (codon 315) and inhA promoter (-5, -8, -15 and -16) genes by Real-time PCR among the different degrees of INH resistance was investigated. Results: Among the growth positive isolates, 68.8% of the resistant isolates had high level INH resistance, where katG was found to be the prominent mutation, with or without combined with inhA mutation. Positive predictive value (PPV) of katG mutation was 84.6% in detecting a high level of INH resistance. Low level resistance was present in 31.3% isolates, conferring mutation in inhA and katG in equal percentage (40%), but no detectable mutations were found in 20% low level INH resistant MTB isolates. The PPV of inhA mutation was 33.3% in detection low level resistance. Conclusion: Most of the INH resistant isolates conferred high level resistance and were associated with katG mutation. Evaluation of level INH resistance before using high dose INH will help to avoid dose dependent toxicity and to determine an appropriate treatment regimen. Bangladesh Medical Res Counc Bull 2023; 49(2): 120-125

In vitro modeling of isoniazid resistance mechanisms in Mycobacterium tuberculosis H37Rv.

Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis, has been a global threat to human beings for several decades. Treating tuberculosis has become more difficult as the prevalence of drug-resistant tuberculosis has increased globally. Evidence suggests that the comprehensive landscape of resistance mechanisms in MTB is ambiguous. More importantly, little is known regarding the series of events connected to resistance mechanisms in MTB before exposure to anti-TB drugs, during exposure to the drugs, and finally, when the MTB becomes resistant after exposure, upon analyses of its genome. We used the wild-type strain of MTB (H37Rv) in an in vitro model for generating induced resistance using a sub-inhibitory concentration of isoniazid, and the generated resistance-associated variants (RAVs) were identified using the whole genome sequencing method. The detection of an inhA promoter mutation (fabG1-15C>T), which results in increased production of InhA protein, was found to be a major mechanism for developing resistance to isoniazid in the first place. We observed adaptation of MTB resistance mechanisms in high isoniazid stress by alteration and abolishment of KatG due to the detection of katG S315N, the common region of mutation that confers isoniazid resistance, along with katG K414N, katG N138S, and katG A162E. Furthermore, we detected the ahpC-72C>T and ahpC 21C>A mutations, but further investigation is needed to determine their role in compensating for the loss of KatG activity. This suggests that increased InhA production is the main mechanism where there are low levels of isoniazid, whereas the alteration of KatG was found to be utilized in mycobacterium with a high concentration of isoniazid. Our work demonstrates that this in vitro approach of generating induced resistance could provide clinically relevant information after the fabG1-15C>T mutation, which is the common mutation found in clinical isolates. Moreover, other mutations detected in this work can also be found in clinical isolates. These findings may shed light on the impact of isoniazid in generating RAV and the resistance mechanism scenario that mycobacterium used under various isoniazid-pressuring conditions. More research is needed to understand better the role of RAV and mechanical resistance events within the mycobacterium genome in promoting a promising drug prediction platform that could lead to the right treatment for patients with MDR-TB and XDR-TB.

Correlation between serum isoniazid concentration and therapeutic response in patients of pulmonary tuberculosis in Central India: A prospective observational study

BackgroundTuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis is one of the top ten causes of death worldwide. Isoniazid (INH) is an important component of anti-tuberculosis therapy (ATT). Low isoniazid levels can serve as a risk factor for the development of treatment failure, relapse of disease and acquired secondary resistance. Hence, serum level of isoniazid becomes a critical factor in determining the treatment outcome of patients on ATT. This study aimed to evaluate the correlation between serum isoniazid concentration and therapeutic response in patients of pulmonary tuberculosis in Central India. MethodsThis was a prospective single cohort observational study conducted at a tertiary care hospital. Therapeutic response in newly diagnosed patients of pulmonary TB was determined based the microbiological, clinical and radiological parameters. Serum INH levels were estimated based on a spectrophotometric method using nano-spectrophotometer. ResultsIn this study, patients had a significant improvement in treatment outcome as evident by a significant decrease in the TB score I at end of IP (p = 0.001) and a significant decline in the Timika score at end of CP (p = 0.001). Although all patients converted to sputum negative at end of CP, 20% remained positive at end of IP. Lower INH levels were seen in 13.3% of the study population. Higher INH levels were observed in sputum converters, patients with low TB score I and low Timika score, although no statistically significant difference was noted (p > 0.05). ConclusionIn this study, we could not find any statistically significant association between serum INH levels and therapeutic outcome of the patients. Further studies on a larger population could provide better understanding about the prevalence of low serum isoniazid levels among the Indian population and establish its relationship with therapeutic outcome. Also, the usage of a comparatively less expensive spectrophotometric method of analysis makes this feasible in almost every district hospital without the need of high-performance liquid chromatography which is costlier and needs more expertise.

Influence of sex on the exposure to isoniazid in patients with pulmonary tuberculosis.

Isoniazid is a key component of tuberculosis treatment. Adequate exposure is a determinant for therapeutic success; however, considerable inter- and intraindividual variations in drug plasma levels can lead to unfavorable outcomes. While some predictors of isoniazid levels are well-known, others, such as sex, yield controversial results, requiring further investigation to optimize exposure. This study investigates whether the sex of patients influences the dose administered and the concentrations of isoniazid in plasma. Levels of isoniazid were associated with the N-acetyltransferase 2 phenotypes. A total of 76 male and 58 female patients were included. Isoniazid was measured by high-performance liquid chromatography, and N-acetyltransferase 2 phenotypes were assessed using molecular techniques. The results show that the dose administered, expressed in mg/kg, was higher in females, but the plasma levels were similar between both sexes. Among patients, 46.2%, 38.8%, and 15% were slow, intermediate, and fast acetylators, respectively. As expected, isoniazid levels were associated with the acetylation phenotypes, with higher concentrations in the slow acetylators. Thus, sex-related difference in isoniazid levels is due to the body weight of patients, and the optimized dose regimen based on patient weight and acetylator phenotypes can improve the treatment outcomes.

A high-throughput LC-MS/MS method for simultaneous determination of isoniazid, ethambutol and pyrazinamide in human plasma.

Tuberculosis (TB) remains a challenging global infectious disease, mainly affecting the lungs. First-line anti-TB drugs play a crucial role in slowing down the rapid spread of TB. In addition, the patient might benefit from therapeutic drug monitoring since it has become an accepted clinical tool for optimizing TB treatment. A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed to monitor the plasma level of isoniazid, ethambutol and pyrazinamide in plasma samples. A one-step extraction procedure using an Ostro™ plate was applied, and extracts were analyzed by gradient elution followed by detection on a mass spectrometer by multiple reaction monitoring mode. The analytes were separated within 4.2min and over the concentration range of 0.2-10μg/ml for isoniazid and ethambutol and 1-65 μg/ml for pyrazinamide. The method was successfully validated according to the European Medicine Agency guideline for the selectivity, linearity and lower limit of detection, precision and accuracy, matrix effect, extraction recovery, carryover, dilution integrity and stability, and applied for quantification of analytes in clinical samples from TB patients. The presented method allows sensitive and reproducible determination of selected anti-TB drugs with advantages such as low sample volume requirement, short run time of analysis, one-step sample preparation procedure with capabilities for phospholipids removal, and a low quantification limit as well as a high degree of selectivity.

SIMULTANEOUS CONTENT ANALYSIS OF RIFAMPICIN, ISONIAZID, AND PYRAZINAMIDE IN TABLET DOSAGE FORM BY SPECTROPHOTOMETRY ULTRAVIOLET WITH DWM AND RSM

Treatment of active tuberculosis requires the use of combinations of drugs. One of the common combination of drugs to serve as anti-tubercular medication is rifampin, isoniazid and pyrazinamide. However, a research conducted by the Food Drug Administration (FDA) concluded that the combination of anti-tubercular medication may pose some patients to the risk of sub-optimal drug exposure, which may lead to less optimal treatment. This study aimed to determine the drug level of combination of anti-tubercular medication, namely rifampin, isomiazid, and pyrazinamide and to develop a spectrophotometric method using the dual wavelength method (DWM) and ratio substaction method (RSM) in tablet preparations on the market without separation. During the preparation, methanol was used as the solvent, followed by dilution, determination of calibration curve, determination of wavelength (λ), measurement, data analysis and validity test with several parameters ranging from linearity, accuracy, precision, LOD, and LOQ. The research revealed that the drug levels of rifampin, isoniazid, and pyrazinamide from the ultraviolet spectrophotometric method using sequential DWM were 100.3±1.8785; 99.98±2.5943; 100.03±2.076 and the results of the ultraviolet spectrophotometric method using RSM sequentially were 99.73±0.5437; 99.84±1.7598; 99.91±1.4762. Both methods succeeded in determining the drug level of the combination of rifampin, isoniazid, and pyrazinamide in tablet preparations without separation and the results of the validation parameters met the requirements.

HupB, a nucleoid-associated protein, is critical for survival of Mycobacterium tuberculosis under host-mediated stresses and for enhanced tolerance to key first-line antibiotics.

To survive and establish its niche, Mycobacterium tuberculosis (Mtb) engages in a steady battle against an array of host defenses and a barrage of antibiotics. Here, we demonstrate that Mtb employs HupB, a nucleoid-associated protein (NAP) as its key player to simultaneously battle and survive in these two stress-inducing fronts. Typically, NAPs are key to bacterial survival under a wide array of environmental or host-mediated stresses. Here, we report that for Mtb to survive under different macrophage-induced assaults including acidic pH, nutrient depletion, oxidative and nitrosative stresses, HupB presence is critical. As expected, the hupB knockout mutant is highly sensitive to these host-mediated stresses. Furthermore, Mtb aptly modulates HupB protein levels to overcome these stresses. We also report that HupB aids Mtb to gain tolerance to high levels of rifampicin (RIF) and isoniazid (INH) exposure. Loss of hupB makes Mtb highly susceptible to even short exposures to reduced amounts of RIF and INH. Overexpressing hupB in Mtb or complementing hupB in the hupB knockout mutant triggers enhanced survival of Mtb under these stresses. We also find that upon loss of hupB, Mtb significantly enhances the permeability of its cell wall by modulating the levels of several surface lipids including phthiocerol dimycocerosates (PDIMs), thus possibly influencing overall susceptibility to host-mediated stresses. Loss of hupB also downregulates efflux pump expression possibly influencing increased susceptibility to INH and RIF. Finally, we find that therapeutic targeting of HupB with SD1, a known small molecule inhibitor, significantly enhances Mtb susceptibility to INH and THP-1 macrophages and significantly reduces MIC to INH. Thus, our data strongly indicate that HupB is a highly promising therapeutic target especially for potential combinatorial shortened therapy with reduced INH and RIF doses.

Potential to Use Fingerprints for Monitoring Therapeutic Levels of Isoniazid and Treatment Adherence

A fingerprint offers a convenient, noninvasive sampling matrix for monitoring therapeutic drug use. However, a barrier to widespread adoption of fingerprint sampling is the fact that the sample volume is uncontrolled. Fingerprint samples (n = 140) were collected from patients receiving the antibiotic isoniazid as part of their treatment, as well as from a drug-naive control group (n = 50). The fingerprint samples were analyzed for isoniazid (INH) and acetylisoniazid (AcINH), using liquid chromatography high-resolution mass spectrometry. The data set was analyzed retrospectively for metabolites known to be present in eccrine sweat. INH or AcINH was detected in 89% of the fingerprints collected from patients and in 0% of the fingerprints collected from the control group. Metabolites lysine, ornithine, pyroglutamic acid, and taurine were concurrently detected alongside INH/AcINH and were used to determine whether the fingerprint sample was sufficient for testing. Given a sufficient sample volume, the fingerprint test for INH use has sensitivity, specificity, and accuracy of 100%. Normalization to taurine was found to reduce intradonor variability. Fingerprints are a novel and noninvasive approach to monitor INH therapy. Metabolites can be used as internal markers to demonstrate a sufficient sample volume for testing and reduce intradonor variability.

Voltammetric Determination of Isoniazid in the Presence of Acetaminophen Utilizing MoS2-Nanosheet-Modified Screen-Printed Electrode.

We used MoS2 nanosheets (MoS2 NSs) for surface modification of screen-printed electrode (MoS2NSs-SPE) aimed at detecting isoniazid (INZ) in the presence of acetaminophen (AC). According to analysis, an impressive catalytic performance was found for INZ and AC electro-oxidation, resulting in an appreciable peak resolution (~320 mV) for both analytes. Chronoamperometry, differential pulse voltammetry (DPV), linear sweep voltammogram (LSV), and cyclic voltammetry (CV) were employed to characterize the electrochemical behaviors of the modified electrode for the INZ detection. Under the optimal circumstances, there was a linear relationship between the peak current of oxidation and the various levels of INZ (0.035–390.0 µM), with a narrow limit of detection (10.0 nM). The applicability of the as-developed sensor was confirmed by determining the INZ and AC in tablets and urine specimens, with acceptable recoveries.

Effect of serum isoniazid level on treatment outcomes among tuberculosis patients with slow response – A retrospective cohort study

BackgroundIn this study, we investigate the effects of low serum TB drug level on treatment outcome among TB patients with slow response in South Korea, where the prevalence of rapid acetylator is relatively high. MethodsAmong the pulmonary TB patients whose treatment outcomes were reported between 2014 and 2018 at Incheon St. Mary hospital, those who underwent TDM because of delayed culture conversion or reversion were included. Primary outcome was microbiological failure defined as (1) positive sputum culture after 120 days of treatment, or (2) culture-confirmed relapse within one year after treatment completion. Patients with culture conversion within 120 days and no relapse were classified as the final conversion group. Clinical characteristics and serum drug concentration at 2 h after administration (C2hr) were compared between those two groups. ResultsA total of 55 pulmonary TB patients were included. Prevalence of subtherapeutic range of C2hr for isoniazid and rifampin was 78.2% and 21.8%, respectively. With one year of follow-up, 21 cases were classified as the microbiological failure group, and 34 cases as the final conversion group. In a multivariable logistic regression model for predicting microbiological failure, C2hr of isoniazid was the most significant predictor after adjusting for the effects of age and sex (adjusted odds ratio, 0.29; p = 0.009). In a tree-based classification model, C2hr of isoniazid with cutoff level 2.5 μg/ml was the most important variable for predicting microbiological failure. ConclusionsLow serum isoniazid level was related to poor treatment outcomes among the TB patients with slow response.

Fasting Enhances Biochemical and Histopathological Changes of Isoniazid Induced Liver Injury in Mouse

Fasting can up regulate the expression of cytochrome P450 2E1 and induce glutathione levels to decrease, protecting the liver from hepatotoxic agents. The aim of this study was to research the mechanism of fasting aggravates isoniazid induced liver injury in mouse. 7 w old male C57 black 6 mice were randomly assigned to two groups: mice fed ad libitum on commercial chow (A group) and mice fasted for 12 h during the day and fed ad libitum on commercial chow (F group). All animals were administered with 100 mg/kg of isoniazid daily by gavage for 6 w (isoniazid levels were selected on basis of screening multiple concentrations). Sera were collected to measure biochemical parameters. Liver sections were stained with hematoxylin and eosin to evaluate hepatic histology. Cytokines was detected by cytometric bead array, flow cytometry. Isoniazid administration (100 mg/kg) daily for 6 w did not significantly induce histological damage in mice of A group. Compared with normal mice, there was no significant difference in serum alanine aminotransferase and aspartate aminotransferase. However, the level of alanine aminotransferase and aspartate aminotransferase levels in F group remained elevated for 6 w, reached its peak on the 3rd d and gradually returned to normal. The liver sections revealed hepatic edema around the central vein on the 3rd d. At 1st or 2nd w, hepatic edema around the central vein with inflammatory cell infiltration and focal necrosis was present. After 4 w, liver histology gradually recovered. Fasting condition influences the cytokine concentration in peripheral blood and liver tissue.

Simultaneous determination of three antituberculosis drugs in the serum of patients with spinal tuberculosis by capillary electrophoresis.

The pharmacokinetic variations of a single drug in an antituberculosis regimen are associated with acquired drug resistance and therapy failure. This study aimed to develop a simple and effective method for monitoring the serum levels of isoniazid (INH), rifampicin (RFP), and pyrazinamide (PZA), three antibiotics used in patients with spinal tuberculosis using capillary electrophoresis (CE). A standard solution of INH, RFP, and PZA was prepared and mixed with serum to prepare the standard curve. The detection limit, quantification limit, precision, stability, repeatability, and sample recovery were determined. Then, INH, RFP, and PZA were measured from the leftover serum samples of all patients with spinal tuberculosis who were treated with 2SHRZ/2.5H2R2Z2 combined with surgery in a tertiary hospital in Qinghai from October 2015 to September 2017. A total of 107 patients with spinal tuberculosis treated using the 2SHRZ/2.5H2R2Z2 regimen combined with surgery were included in this study. All three antibiotics had linear standard curves with high correlation coefficients (R2 = 0.9997, 0.9994, and 0.9986). The recovery rates were 98.1% for INH, 96.5% for PZA, and 97.2% for RFP. The results from the serum samples showed that the plasma concentrations of INH (4.989 ± 1.692 μg mL-1) and RFP (9.400 ± 1.711 μg mL-1) reached effective therapeutic concentrations in all patients, but not PZA (33.860 ± 1.830 μg mL-1). The CE method for measuring INH, RFP, and PZA simultaneously in serum samples of patients with spinal tuberculosis is simple, rapid, and sensitive. This method is suitable for the routine monitoring of INH, RFP, and PZA concentrations in the serum of patients with spinal tuberculosis.

A simple Simultaneous UV Spectrophotometric Method to Determine Isoniazid and Rifampicin Contents in One Combined Tablet

Isoniazid and rifampicin are the first-line anti-tuberculosis drugs in the advanced phase. This study aimed at validating the method to determine the levels of isoniazid and rifampicin contents in one serve of combined tablet circulating at Pramuka market using simultaneous analysis of Ultraviolet Spectrophotometry with methanol as a solvent. The maximum wavelength of isoniazid and rifampicin obtained was 261 nm and 337 nm, respectively. The method used to confirm the validity here includes linearity, the limit of detection (LOD), limit of quantitation (LOQ), accuracy, and precision under the ICH guidelines. The results of the method validation for isoniazid and rifampicin were as follow: linearity (R2) in the range 5-25 µg / mL showed about 0.9998 and 0.9997, the limit of detection (LOD) 0.4026 µg/mL and 0.4952 µg / mL, and the limit of quantification (LOQ) 1.3421 µg / mL and 1.6508 µg / mL respectively. Besides, the accuracy-test (% recovery) was in the range of 100.44% ± 0.41% to 107.26% ± 0.28%, while the precision test (% RSD) was less than 2%. The determination of the contents was carried out on samples purchased at Pramuka Market with predetermined criteria and obtained levels of active ingredients ranging from 92.774% ± 0.39% to 103.51% ± 0.41%. The method validation to determine the levels of isoniazid and rifampicin contents in one serve of combined tablet using simultaneous analysis of Ultraviolet (UV) Spectrophotometry with methanol as a solvent is recommended for preparation analysis at the market.

Isoniazid causes heart looping disorder in zebrafish embryos by the induction of oxidative stress

BackgroundThe cardiotoxicity of isoniazid on zebrafish embryos and its underlying mechanism is unclear.MethodsHere, we exposed zebrafish embryos at 4 h post-fertilization to different levels of isoniazid and recorded the morphology and number of malformed and dead embryos under the microscope.ResultsThe high concentration of isoniazid group showed more malformed and dead embryos than the low concentration of isoniazid group and control group. The morphology of the heart and its alteration were visualized using transgenic zebrafish (cmlc2: GFP) and confirmed by in situ hybridization. The negative effects of isoniazid on the developing heart were characterized by lower heart rate and more heart looping disorders. Mechanistically, PCR showed decreased expression of heart-specific transcription factors when exposed to isoniazid. Oxidative stress was induced by isoniazid in cardiomyocytes, mediated by decreased activities of catalase and superoxide dismutase, which were rescued by scavengers of reactive oxygen species.ConclusionIn conclusion, this study demonstrated that isoniazid led to heart looping disturbance by the downregulation of cardiac-specific transcription factors and induction of cardiomyocyte apoptosis.