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Rifampicin, essential for long-term tuberculosis treatment, requires rigorous control of non-therapeutic impurities due to their potential adverse, including mutagenic effects. Reports on control strategies for genotoxic impurities in rifampicin have been limited. This study introduced an analytical method to identify potential genotoxic impurities from the synthesis of raw materials. The structure of the 25-deacetyl-23-acetyl-rifampicin genotoxic impurity was confirmed using nuclear magnetic resonance, high-resolution mass spectrometry (HRMS), and high-performance liquid chromatography (HPLC). An HPLC-HRMS method was established and validated for detecting another genotoxic impurity, 1-amino-4-methylpiperazine, adhering to the International Council on Harmonization guidelines, which include specificity, linearity, detection and quantification limits, accuracy, precision, and robustness. These developments improve the quality control strategy for genotoxic impurities in rifampicin, ensuring product safety., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Rifampicin (RFP) has demonstrated potent antibacterial effects in the treatment of pulmonary tuberculosis. However, the serious adverse effects on the liver intensively limit the clinical usage of the drug. Deacetylation greatly reduces the toxicity of RFP but also retains its curative activity. Here, we found that Krüppel-like factor 15 (KLF15) repressed the expression of the major RFP detoxification enzyme Cyp3a11 in mice via both direct and indirect mechanisms. Knockout of hepatocyte KLF15 induced the expression of Cyp3a11 and robustly attenuated the hepatotoxicity of RFP in mice. In contrast, overexpression of hepatic KLF15 exacerbated RFP-induced liver injury as well as mortality. More importantly, the suppression of hepatic KLF15 expression strikingly restored liver functions in mice even after being pretreated with overdosed RFP. Therefore, this study identified the KLF15-Cyp3a11 axis as a novel regulatory pathway that may play an essential role in the detoxification of RFP and associated liver injury. SIGNIFICANCE STATEMENT: Rifampicin has demonstrated antibacterial effects in the treatment of pulmonary tuberculosis. However, the serious adverse effects on the liver limit the clinical usage of the drug. Permanent depletion and transient inhibition of hepatic KLF15 expression significantly induced the expression of Cyp3a11 and robustly attenuated mouse hepatotoxicity induced by RFP. Overall, our studies show the KLF15-Cyp3a11 axis was identified as a novel regulatory pathway that may play an essential role in the detoxification of RFP and associated liver injury., (Copyright © 2024 by The Author(s).)

During our screening for antibiotics against Mycobacterium avium complex (MAC) with a mass spectrometry network-based indexing approach, a new compound named kimidinomycin was isolated from the culture broth of Streptomyces sp. KKTA-0263 by solvent extraction, HP20 column chromatography, and preparative HPLC. From the structural elucidation, the compound possesses a 38-membered macrolide structure with an N-methylguanidyl group at the terminal side chain. The compound exhibited antimycobacterial activity against M. avium, M. intracellulare, M. smegmatis, and M. bovis BCG with respective MIC values of 12.5, 0.78, 12.5, and 25.0 µg ml -1 ., (© 2021. The Author(s), under exclusive licence to the Japan Antibiotics Research Association.)

Objectives: Anti-TB drugs-isoniazid and rifampicin induced hepatotoxicity present a significant clinical problem. We aimed to evaluate the beneficial effect of gallic acid in anti-TB drug-induced liver injury in vivo and for the mechanism of action, we explored the influence of gallic acid on Nrf2 and NF-κB pathways., Methods: We assessed serum liver function tests and histopathological analysis for the preventive effect of gallic acid on liver injury. For exploring the beneficial mechanism, we studied Nrf2 and NF-κB signalling pathways using molecular assays. Subsequently, we conducted in vitro cytotoxicity assays with Nrf2(ML385) and NF-κB(BAY 11-7085) antagonists., Key Findings: Gallic acid co-administration attenuated the elevation of liver function enzymes, hepatic necrosis and inflammation compared to the anti-TB drug treatment alone. Mechanistic investigations reveal that gallic acid increased Nrf2 activation and induction of its downstream targets, preventing cytotoxicity by isoniazid and rifampicin. The protective effect of gallic acid diminished in the presence of Nrf2 antagonists in vitro. Furthermore, we found that gallic acid treatment inhibited NF-κB/TLR-4 axis upregulated by the anti-TB drugs., Conclusions: Gallic acid is effective in preventing isoniazid and rifampicin induced hepatotoxicity in vivo by improving the redox homeostasis by activating Nrf2 and inhibiting NF-κB signalling pathways., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Royal Pharmaceutical Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Prolonged treatment with rifampicin (RFP), a first-line antibacterial agent used in the treatment of drug-sensitive tuberculosis, may cause various side effects, including metabolic disorders. The nuclear factor (erythroid-derived 2)-like 2 (NFE2L2, also known as NRF2) plays an essential regulatory role in cellular adaptive responses to stresses via the antioxidant response element (ARE). Our previous studies discovered that NRF2 regulates the expression of CCAAT-enhancer-binding protein β (Cebpb) and peroxisome proliferator-activated receptor gamma (Pparg) in the process of adipogenesis. Here, we found that prolonged RFP treatment in adult male mice fed a high-fat diet developed insulin resistance, but reduced fat accumulation and decreased expression of multiple adipogenic genes in white adipose tissues. In 3 T3-L1 preadipocytes, RFP reduced the induction of Cebpb, Pparg and Cebpa at mRNA and protein levels in the early and/or later stage of hormonal cocktail-induced adipogenesis. Mechanistic investigations demonstrated that RFP inhibits NRF2-ARE luciferase reporter activity and expression of NRF2 downstream genes under normal culture condition and in the early stage of adipogenesis in 3 T3-L1 preadipocytes, suggesting that RFP can disturb adipogenic differentiation via NRF2-ARE interference. Taken together, we demonstrate a potential mechanism that RFP impairs adipose function by which RFP likely inhibits NRF2-ARE pathway and thereby interrupts its downstream adipogenic transcription network., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Tuberculosis (TB) is one of the deadliest infectious diseases in humankind history. Although, drug sensible TB is slowly decreasing, at present the rise of TB cases produced by multidrug-resistant (MDR) and extensively drug-resistant strains is a big challenge. Thus, looking for new therapeutic options against these MDR strains is mandatory. In the present work, we studied, in BALB/c mice infected with MDR strain, the therapeutic effect of supra-pharmacological doses of the conventional primary antibiotics rifampicin and isoniazid (administrated by gavage or intratracheal routes), in combination with recombinant human hepatocyte growth factor (HGF). This high dose of antibiotics administered for 3 months, overcome the resistant threshold of the MDR strain producing a significant reduction of pulmonary bacillary loads but induced liver damage, which was totally prevented by the administration of HGF. To address the long-term efficiency of this combined treatment, groups of animals after 1 month of treatment termination were immunosuppressed by glucocorticoid administration and, after 1 month, mice were euthanized, and the bacillary load was determined in lungs. In comparison with animals treated only with a high dose of antibiotics, animals that received the combined treatment showed significantly lower bacterial burdens. Thus, treatment of MDR-TB with very high doses of primary antibiotics particularly administrated by aerial route can produce a very good therapeutic effect, and its hepatic toxicity can be prevented by the administration of HGF, becoming in a new treatment modality for MDR-TB., (© 2019 Wiley Periodicals, Inc.)

First-line antituberculosis drugs, namely, isoniazid (INH), rifampicin (RIF), and pyrazinamide (PZA), contribute to diverse pathological complications. Testicular toxicity is one such complication. Berberis aristata DC is an herb with potentially curative characteristics. The aim of this study was to test whether extract of Berberis aristata DC (Berberidaceae) has curing potential against testicular toxicity. Characterization of extract was done using ultra-performance liquid chromatography along with acute toxicity testing. Antioxidant activity of extract was checked by DPPH inhibition assay and H 2 O 2 scavenging assay. Rats were dosed once daily for 28 days in groups: control group (saline), toxicant group (30.85 mg/kg body weight INH + 61.7 mg/kg body weight RIF + 132.65 mg/kg body weight PZA), treatment groups (TB drugs + 150/300 mg/kg body weight extract) and standard group (TB drugs +100 mg/kg body weight silymarin). Spectrophotometric evaluations of lipid peroxidation (LPO), reduced glutathione (GSH), superoxide dismutase (SOD), glutathione-S-transferase (GST), and catalase (CAT) content in testes were done using standard protocols. DNA fragmentation and histopathological studies were performed to check the damage at the cellular level. Acute toxicity studies revealed LD 50 > 5 g/Kg body weight of B. aristata extract. IC 50 for DPPH free-radical scavenging activity and H 2 O 2 scavenging assay were 44.78 µg/mL and 85.28 µg/mL, respectively. Results revealed significant increase in thiobarbituric acid reactive substances, decrease in glutathione and different antioxidants levels, DNA fragmentation pattern, and changes in histology in toxicant group. All the changes were absent in high-dose (300 mg/kg body weight) extract treatment group. This work proved that B. aristata extract has protective efficacy against testicular damage caused by anti-TB drugs.

Methimazole (MMI) is a widely used drug for hyperthyroidism. However, its clinical use is associated with hepatotoxicity. Though the precise mechanism of hepatic damage is still far from clear, role of metabolic activation and reactive metabolites have been implicated. The present study was designed to investigate the role of enzyme induction in bioactivation based hepatotoxicity of methimazole in mice. Thirty male mice were randomly divided into five groups. Hepatotoxicity was induced by single intraperitoneal injection of methimazole (1000mg/kg). Pretreatment with rifampicin which is a potent enzyme inducer was carried out for 6 days prior to administration of methimazole. The extent of hepatic damage was determined by measuring serum alanine aminotransferase (ALT) and alkaline phosphatase (ALP) along with histopathological grading of liver samples. The elevated levels of biochemical markers by methimazole were potentiated by pretreatment with rifampicin. This potentiation of hepatic injury was also observed in liver histopathological examination. These findings suggest induction of microsomal enzymes as a potentiating factor of methimazole induced hepatotoxicity.

Objective: Pulmonary delivery of antibiotics will decrease the required dose for efficient treatment of lung infections and reduce systemic side effects of the drug. The objective was to evaluate the applicability of poly(ethylene carbonate) (PEC) for the preparation of inhalable, antibiotic-containing particles., Methods: Rifampicin (RF)-loaded microparticles were prepared by electrospraying a carrier matrix of polylactic acid (PLA) with 0%, 5% and 10% PEC., Key Findings: Prepared particles had an aerodynamic diameter between 4 and 5 μm. Within 60 min, PEC-containing particles released 35-45% of RF, whereas PLA particles released only 15% of RF. Irrespective of particle composition, uptake of RF by macrophages was improved to 40-60% when formulated in microparticles compared to 0.4% for RF in solution, and intracellular localisation of particles was confirmed using confocal microscopy. Effect on macrophage and alveolar cell viability was similar for all particles whereas the minimal inhibitory concentrations against Pseudomonas aeruginosa and Escherichia coli for RF-containing PEC particles were twofold lower than for PLA particles, explained by the faster release of RF from PEC-containing particles., Conclusions: The inclusion of PEC in PLA microparticles increased the release of RF and the inhibitory effect against two bacteria species while displaying physical particle properties similar to PLA particles., (© 2018 Royal Pharmaceutical Society.)

Objectives: The aim of this study is to evaluate the hepatoprotective effect of Lasianthera africana (Icacinaceae) against isoniazid (INH) and rifampicin (RIF)-induced liver damage in rats., Methods: The hepatoprotective effects of hot aqueous L. africana (HALA) leaf extract (0.1-1 g/kg) and silymarin (50 mg/kg) were assessed in a model of oxidative liver damage induced by RIF and INH (100 mg/kg each) in Wistar rats for 28 days. Biochemical markers of hepatic damage such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were assessed. The antioxidant statuses of plasma glutathione peroxidase (GSPx), glutathione reductase (GSH), catalase (CAT) and superoxide dismutase (SOD) and lipid peroxidation were evaluated., Results: The pretreatment of INH and RIF decreased hematological indices and the antioxidant levels (P < 0.001) and increased the levels of liver marker enzymes (P < 0.001). However, pretreatment with HALA extract and silymarin provoked significant elevation of hematological indices. The levels of AST, ALT, and ALP were depressed (P < 0.001). Total triglycerides, total cholesterol, total bilirubin and low-density lipoprotein were decreased (P < 0.001). However, high-density lipoprotein, bicarbonate, and electrolytes like chloride and potassium were elevated (P < 0.001), but sodium was depressed (P < 0.05). Additionally, GSH, GSPx, SOD and CAT were elevated (P < 0.01) and malondialdehyde was depressed (P < 0.001) when compared to the RIF-INH-treated rats. Histopathological evaluations support hepatoprotective activity., Conclusion: This study demonstrated that HALA leaf extract attenuated RIF-INH-induced hepatotoxicity. L. africana could be exploited in management of RIF-INH-induced hepatitis., (Copyright © 2018 Shanghai Changhai Hospital. Published by Elsevier B.V. All rights reserved.)

Background: The delivery of antitubercular drugs through direct lung targeting can lead to reduction in the dose as well as side effects of the drug. In the present investigation, carrier (lactose)-based dry-powder inhaler of rifampicin was prepared to achieve direct targeting of the drug into the lungs., Methods: The dry powder inhaler formulation was prepared by simply mixing micronized rifampicin with coarse and fine lactose preblend. Preliminary blends of the drug were prepared with various lactose grades (Inhalac ® , Respitose, ® and Lactohale ® ). Rotahaler ® and Revolizer ® were evaluated for the performance. The 3 2 factorial design was used to optimize the amount of drug (X 1 ) and amount of fine lactose (X 2 ). In vitro lung deposition was carried out using Andersen Cascade Impactor. The % cell viability studies of the formulation were carried out using murine macrophage J774 cell lines. The in vivo toxicity was determined using histopathology. Further in vivo pulmonary pharmacokinetics of the developed dry-powder inhaler (DPI) formulation was carried out in comparison to the marketed formulation in the rat lungs., Results: Based on preliminary trials, Inhalac 230 and Inhalac 400 were selected as coarse and fine lactose grades, respectively. Rotahaler ® exhibited better DPI performance with the evaluated drug blends. The mass median aerodynamic diameter (MMAD) was in the range of 4.3-5.8 μm with the maximum fine particle fraction of 28.9%. The formulation exhibited negligible cytotoxicity on macrophage J774 cell lines with about 75%-80% cell viability at 6- and 12-hour exposure. The histopathological examination revealed negligible toxicity of DPI in comparison to the marketed formulation. The in vivo pulmonary pharmacokinetic studies of the DPI formulation in rats showed higher drug concentration in lungs in comparison to the marketed formulation., Conclusion: The carrier-mediated dry-powder inhaler of rifampicin could serve as an improved and efficient system for local targeting of drugs into the lungs.

Endoplasmic reticulum (ER) stress-induced cell injury plays an important role in the development of drug-induced liver injury (DILI). However, little is known about the contribution of ER stress to RFP-induced cell injury. In our study, L02 cells were treated with different concentrations of RFP for different time intervals, and cell apoptosis, the survival rate, and the gene and protein expression of GRP78, PERK, ATF4, and CHOP were measured. Additionally, L02 cells were transfected with CHOP-siRNA or a CHOP-over expression plasmid or administered 4-PBA before treatment with RFP. We found that RFP increased the cell apoptosis rate, decreased cell survival, and increased the protein and gene levels of GRP78, PERK, ATF4 and CHOP in both a dose-dependent and a time-dependent manner. Following the transient knockdown of CHOP and treatment with RFP, cell apoptosis decreased and the survival rate increased. Overexpression of CHOP produced the opposite effects. Treatment with 4-PBA decreased the protein and gene expression of GRP78, PERK, ATF4 and CHOP. Additionally, 4-PBA reduced cell apoptosis, increased cell survival and decreased the level of ALT, AST, AKP, LDH and ATP in the cell culture supernatant. These results indicate that 4-PBA alleviates RFP-induced injury in L02 cells via inhibition of the PERK-ATF4-CHOP pathway., (Copyright © 2016 Elsevier B.V. All rights reserved.)

This work aimed to design, develop, and characterize a lipid nanocarrier system for the selective delivery of rifabutin (RFB) to alveolar macrophages. Lipid nanoparticles, specifically nanostructured lipid carriers (NLC), were synthetized by the high-shear homogenization and ultrasonication techniques. These nanoparticles were designed to exhibit both passive and active targeting strategies to be efficiently internalized by the alveolar macrophages, traffic to the acidified phagosomes and phagolysosomes, and release bactericidal concentrations of the antituberculosis drug intracellularly. NLC that could entrap RFB were prepared, characterized, and further functionalized with mannose. Particles' diameter, zeta potential, morphology, drug% entrapping efficiency, and drug release kinetics were evaluated. The mannose coating process was confirmed by Fourier transform infrared. Further, the cytotoxicity of the formulations was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay in A549, Calu-3, and Raw 264.7 cells. The diameter of NLC formulations was found to be in the range of 175-213 nm, and drug entrapping efficiency was found to be above 80%. In addition, high storage stability for the formulations was expected since they maintained the initial characteristics for 6 months. Moreover, the drug release was pH-sensitive, with a faster drug release at acidic pH than at neutral pH. These results pose a strong argument that the developed nanocarrier can be explored as a promising carrier for safer and more efficient management of tuberculosis by exploiting the pulmonary route of administration.

Background: The lung is the primary entry site and target for Mycobacterium tuberculosis; more than 80% of the cases reported worldwide are of pulmonary tuberculosis. Hence, direct delivery of anti-tubercular drugs to the lung would be beneficial in reducing both, the dose required, as well as the duration of therapy for pulmonary tuberculosis. In the present study, microsphere-based dry powder inhalation systems of the anti-tubercular drugs, rifampicin and rifabutin, were developed and evaluated, with a view to achieve localized and targeted delivery of these drugs to the lung., Methods: The drug-loaded chitosan microparticles were prepared by an ionic gelation method, followed by spray-drying to obtain respirable particles. The microparticles were evaluated for particle size and drug release. The drug-loaded microparticles were then adsorbed onto an inhalable lactose carrier and characterized for in vitro lung deposition on an Andersen Cascade Impactor (ACI) followed by in vitro uptake study in U937 human macrophage cell lines. In vivo toxicity of the developed formulations was evaluated using Sprague Dawley rats., Results: Both rifampicin and rifabutin-loaded microparticles had MMAD close to 5 μm and FPF values of 21.46% and 29.97%, respectively. In vitro release study in simulated lung fluid pH 7.4 showed sustained release for 12 hours for rifampicin microparticles and up to 96 hours for rifabutin microparticles, the release being dependent on both swelling of the polymer and solubility of the drugs in the dissolution medium. In vitro uptake studies in U937 human macrophage cell line suggested that microparticles were internalized within the macrophages. In vivo acute toxicity study of the microparticles in Sprague Dawley rats revealed no significant evidence for local adverse effects., Conclusion: Thus, spray-dried microparticles of the anti-tubercular drugs, rifampicin and rifabutin, could prove to be an improved, targeted, and efficient system for treatment of tuberculosis.

Rifampicin (RIF) was encapsulated into solid lipid nanoparticles (SLNs) to overcome its poor and unreliable oral bioavailability. Novel microemulsification method with high drug loading (50%) and entrapment efficiency (∼67%) was developed (Indian Patent Application 3356/DEL/2013). RIF-SLNs were characterized using TEM, AFM, DSC and XRD. Near neutral SLNs (zeta -3.5 ± 0.8), with average particle size of 130.0 ± 22.6 nm showed 70.12% release in phosphate buffer pH 6.8 in 9 days. Single oral dose (50mg/kg) pharmacokinetic studies in Wistar rats indicated 8.14 times higher (in comparison to free RIF) plasma bioavailability with sustained levels for 5 days. Pharmacodynamic parameters viz. TMIC (120 h; time for which plasma levels were above MIC of 0.2 μg/ml), AUC0-∞/MIC (1868.9h) and Cmax/MIC (75.6) for RIF-SLNs were greater than free RIF by 2.5, 8.2 and 6.6 times, respectively. Similar LD50 (1570 mg/kg) and absence (or reversal in satellite group) of adverse events in repeat dose (three doses; highest dose was up to 50 times the human therapeutic dose) toxicity studies confirmed safety of RIF-SLNs. Improved pharmacokinetic profile of RIF-SLNs can be translated to a reduced dose and dosage frequency of RIF, thus resulting in lower or no hepatotoxicity commonly associated with its use., (Copyright © 2015 Elsevier B.V. All rights reserved.)