Single-Dose Rifampicin Leprosy Chemoprophylaxis for Household Contacts in Kiribati: An Audit of a Combined Retrospective and Prospective Approach.

Kiribati is a Pacific Island nation with a widely dispersed population and one of the highest rates of leprosy worldwide. Single-dose rifampicin post-exposure prophylaxis (SDR-PEP) of leprosy contacts has reduced new case detection rates in controlled trials. In 2018, an SDR-PEP programme was introduced in Kiribati that included screening and chemoprophylaxis of household contacts of leprosy cases retrospectively (2010-2017) and prospectively (2018-2022). We conducted a retrospective audit to determine the comprehensiveness, timeliness and feasibility of the SDR-PEP programme. Overall, 13,641 household contacts were identified (9791 in the retrospective and 3850 in the prospective cohort). In the retrospective cohort, 1044 (11%) contacts were absent, 403 (4%) were ineligible for SDR, and 42 new cases were detected (0.4%) Overall, SDR coverage was 84.7%. In the prospective cohort, 164 (4%) contacts were absent, 251 (7%) were ineligible for SDR, and 23 new cases were diagnosed (0.6%). Overall, SDR coverage was 88.1%. Across both cohorts, there were 23 SDR refusals. The median time to SDR administration was 220 days (IQR 162-468) and 120 days (IQR 36-283) for the retrospective and prospective cohorts, respectively. SDR was readily accepted in both cohorts. The new case detection rate (0.5%) is consistent with that in other studies. Overall SDR coverage in both the retrospective and prospective phases met programmatic expectations.

Adverse reactions induced by MDT/WHO (Rifampicin+Clofazimine+Dapsone) and ROM (Rifampicin+Ofloxacin+Minocycline) regimens used in the treatment of leprosy: a cohort study in a National Reference Center in Brazil.

Background: Recommended standard treatment for leprosy is multidrugtherapy (MDT/WHO), consisting Rifampicin+Dapsone+Clofazimine. Other medications are recommended in cases of resistance, adverse reactions and intolerances, including ROM regimen, Rifampicin+Ofloxacin+Minocycline. Therefore, pharmacovigilance is an important tool in understanding these adverse drug reactions (ADRs), supporting pharmacotherapy management and medication safety. This study seeks to evaluate ADRs comparing two therapeutic regimens, MDT and ROM, used in treatment of patients with leprosy, analyzing prognostic factors regarding risk and safety. Methods:A retrospective cohort study was performed by assessing medical records of 433 patients diagnosed with leprosy from 2010 to 2021 at a National Reference Center in Brazil. They were subject to 24 months or more of treatment with MDT or ROM regimens. ADR assessments were analyzed by two experienced researchers, who included clinical and laboratory variables, correlating them with temporality, severity and the causality criteria of Naranjo and WHO. Results: The findings observed an average of 1.3 reactions/patient. Out of individuals experiencing reactions, 67.0% (69/103) were utilizing MDT/MB, while 33.0% (34/103) were using ROM. The median time for ADR of 79 days for MDT and 179 days for ROM. In first reaction, Dapsone was the most frequently involved medication; the most affected system was hematopoietic. As compared to Clofazimine, results indicated that use of Dapsone was associated with 7% increased risk of ADR occurrence (HR: 1.07; p = 0.866). Additionally, Rifampicin was linked to 31% increased risk of ADRs (HR: 1.31; p = 0.602); and Ofloxacin showed 35% elevated risk (HR: 1.35; p = 0.653). Conversely, results for Minocycline indicated 44% reduction in the risk of ADRs (HR: 0.56; p = 0.527), although statistical significance was not reached. The use of MDT conferred 2.51 times higher risk of developing ADRs in comparison to ROM. Conclusion: The comparison between MDT and ROM revealed that MDT caused more ADRs, and these reactions were more severe, indicating less safety for patients. Dapsone was the most common medication causing ADRs, followed by Rifampicin. The combination with Clofazimine was associated with an additional risk of ADRs, warranting further studies to confirm this hypothesis. Given the high magnitude of ADRs, healthcare teams need to monitor patients undergoing leprosy treatment with focus on pharmacovigilance.

Preparation and Characterization of a Rifampicin Coamorphous Material with Tromethamine Coformer: An Experimental-Theoretical Study.

Rifampicin (RIF) is an antibiotic used to treat tuberculosis and leprosy. Even though RIF is a market-available drug, it has a low aqueous solubility, hindering its bioavailability. Among the strategies for bioavailability improvement of poorly soluble drugs, coamorphous systems have been revealed as an alternative in the increase of the aqueous solubility of drug systems and at the same time also increasing the amorphous state stability and dissolution rate when compared with the neat drug. In this work, a new coamorphous form from RIF and tromethamine (TRIS) was synthesized by slow evaporation. Structural, electronic, and thermodynamic properties and solvation effects, as well as drug-coformer intermolecular interactions, were studied through density functional theory (DFT) calculations. Powder X-ray diffraction (PXRD) data allowed us to verify the formation of a new coamorphous. In addition, the DFT study indicates a possible intermolecular interaction by hydrogen bonds between the available amino and carbonyl groups of RIF and the hydroxyl and amino groups of TRIS. The theoretical spectra obtained are in good agreement with the experimental data, suggesting the main interactions occurring in the formation of the coamorphous system. PXRD was used to study the physical stability of the coamorphous system under accelerated ICH conditions (40 °C and 75% RH), indicating that the material remained in an amorphous state up to 180 days. The thermogravimetry result of this material showed a good thermal stability up to 153 °C, and differential scanning calorimetry showed that the glass temperature (Tg) was at 70.0 °C. Solubility studies demonstrated an increase in the solubility of RIF by 5.5-fold when compared with its crystalline counterpart. Therefore, this new material presents critical parameters that can be considered in the development of new coamorphous formulations.

The PEP++ study protocol: a cluster-randomised controlled trial on the effectiveness of an enhanced regimen of post-exposure prophylaxis for close contacts of persons affected by leprosy to prevent disease transmission.

BACKGROUND: Leprosy is an infectious disease with a slow decline in global annual caseload in the past two decades. Active case finding and post-exposure prophylaxis (PEP) with a single dose of rifampicin (SDR) are recommended by the World Health Organization as measures for leprosy elimination. However, more potent PEP regimens are needed to increase the effect in groups highest at risk (i.e., household members and blood relatives, especially of multibacillary patients). The PEP++ trial will assess the effectiveness of an enhanced preventive regimen against leprosy in high-endemic districts in India, Brazil, Bangladesh, and Nepal compared with SDR-PEP. METHODS: The PEP++ study is a cluster-randomised controlled trial in selected districts of India, Brazil, Bangladesh, and Nepal. Sub-districts will be allocated randomly to the intervention and control arms. Leprosy patients detected from 2015 - 22 living in the districts will be approached to list their close contacts for enrolment in the study. All consenting participants will be screened for signs and symptoms of leprosy and tuberculosis (TB). In the intervention arm, eligible contacts receive the enhanced PEP++ regimen with three doses of rifampicin (150 - 600 mg) and clarithromycin (150 - 500 mg) administered at four-weekly intervals, whereas those in the control arm receive SDR-PEP. Follow-up screening for leprosy will be done for each individual two years after the final dose is administered. Cox' proportion hazards analysis and Poisson regression will be used to compare the incidence rate ratios between the intervention and control areas as the primary study outcome. DISCUSSION: Past studies have shown that the level of SDR-PEP effectiveness is not uniform across contexts or in relation to leprosy patients. To address this, a number of recent trials are seeking to strengthen PEP regimens either through the use of new medications or by increasing the dosage of the existing ones. However, few studies focus on the impact of multiple doses of chemoprophylaxis using a combination of antibiotics. The PEP++ trial will investigate effectiveness of both an enhanced regimen and use geospatial analysis for PEP administration in the study communities. TRIAL REGISTRATION: NL7022 on the Dutch Trial Register on April 12, 2018. Protocol version 9.0 updated on 18 August 2022 https://www.onderzoekmetmensen.nl/en/trial/23060.

Comparison of antiphenolic glycolipid-1 antibody levels in seropositive contacts of leprosy after 2 years of single-dose rifampicin as postexposure prophylaxis.

Background: Leprosy is still a global problem, especially in developing countries, including Indonesia. Ineffective prevention of leprosy leads to active transmission of the disease. World Health Organization (WHO) recommend post-exposure prophylaxis (PEP) with single dose of rifampicin (SDR) for leprosy patients. Previous study showed protective effect of SDR against leprosy, especially for the first 2 years. Hence, the use of PEP and IgM anti PGL-1 examination are required to suspend the chain of leprosy transmission. This study evaluated the effectiveness of SDR administration by comparing IgM anti-PGL-1 antibody levels in seropositive household contacts before and after 2 years of SDR administration. Methods: Analytical observational laboratory study comparing IgM anti PGL-1 antibody levels before and after 2 years of SDR administration in leprosy contacts, with a prospective follow-up study design. We conducted this study from December 2022 to January 2023 at Dr. Mohammad Hoesin General Hospital Palembang. All seropositive household contacts of leprosy who had been administrated SDR 2 years ago were included, then PGL-1 antibody levels were examined. Results: The use of SDR showed significant improvement in leprosy contacts after 2 years (P=0.000). The median antibody level before SDR administration was 1,209.20 (615.81 - 4,353.60), which decrease to 146.03 (0 - 2,487.80) U/mL after 2 years. There was statistically significant relationship between history of BCG vaccination (P=0.003) and IgM PGL-1 antibody levels after 2 years of SDR administration. Conclusion: There is a significant decrease in IgM anti PGL-1 antibody levels among leprosy contacts after 2 years of SDR chemoprophylaxis administration.

The pipeline for drugs for control and elimination of neglected tropical diseases: 2. Oral anti-infective drugs and drug combinations for off-label use.

In its 'Road map for neglected tropical diseases 2021-2030', the World Health Organization outlined its targets for control and elimination of neglected tropical diseases (NTDs) and research needed to achieve them. For many NTDs, this includes research for new treatment options for case management and/or preventive chemotherapy. Our review of small-molecule anti-infective drugs recently approved by a stringent regulatory authority (SRA) or in at least Phase 2 clinical development for regulatory approval showed that this pipeline cannot deliver all new treatments needed. WHO guidelines and country policies show that drugs may be recommended for control and elimination for NTDs for which they are not SRA approved (i.e. for 'off-label' use) if efficacy and safety data for the relevant NTD are considered sufficient by WHO and country authorities. Here, we are providing an overview of clinical research in the past 10 years evaluating the anti-infective efficacy of oral small-molecule drugs for NTD(s) for which they are neither SRA approved, nor included in current WHO strategies nor, considering the research sponsors, likely to be registered with a SRA for that NTD, if found to be effective and safe. No such research has been done for yaws, guinea worm, Trypanosoma brucei gambiense human African trypanosomiasis (HAT), rabies, trachoma, visceral leishmaniasis, mycetoma, T. b. rhodesiense HAT, echinococcosis, taeniasis/cysticercosis or scabies. Oral drugs evaluated include sparfloxacin and acedapsone for leprosy; rifampicin, rifapentin and moxifloxacin for onchocerciasis; imatinib and levamisole for loiasis; itraconazole, fluconazole, ketoconazole, posaconazole, ravuconazole and disulfiram for Chagas disease, doxycycline and rifampicin for lymphatic filariasis; arterolane, piperaquine, artesunate, artemether, lumefantrine and mefloquine for schistosomiasis; ivermectin, tribendimidine, pyrantel, oxantel and nitazoxanide for soil-transmitted helminths including strongyloidiasis; chloroquine, ivermectin, balapiravir, ribavirin, celgosivir, UV-4B, ivermectin and doxycycline for dengue; streptomycin, amoxicillin, clavulanate for Buruli ulcer; fluconazole and isavuconazonium for mycoses; clarithromycin and dapsone for cutaneous leishmaniasis; and tribendimidine, albendazole, mebendazole and nitazoxanide for foodborne trematodiasis. Additional paths to identification of new treatment options are needed. One promising path is exploitation of the worldwide experience with 'off-label' treatment of diseases with insufficient treatment options as pursued by the 'CURE ID' initiative.

Predicted Pharmacokinetic Interactions Between Hormonal Contraception and Single or Intermittently Dosed Rifampicin.

The scale-up of rifampicin-based prevention regimens is an essential part of the global leprosy strategy. Daily rifampicin may reduce the effectiveness of the oral contraceptive pill (OCP), but little is known about the effects of rifampicin at the less frequent dosing intervals used for leprosy prophylaxis. As many women of reproductive age rely on OCP for family planning, evaluating the interaction with less-than-daily rifampicin regimens would enhance the scalability and acceptability of leprosy prophylaxis. Using a semi-mechanistic pharmacokinetic model of rifampicin induction, we simulated predicted changes in OCP clearance when coadministered with varying rifampicin dosing schedules. Rifampicin given as a single dose (600 or 1200 mg) or 600 mg every 4 weeks was not predicted to result in a clinically relevant interaction with OCP, defined as a >25% increase in clearance. Simulations of daily rifampicin were predicted to increase OCP clearance within the range of observed changes previously reported in the literature. Therefore, our findings suggest that OCP efficacy will be maintained when coadministered with rifampicin-based leprosy prophylaxis regimens of 600 mg once, 1200 mg once, and 600 mg every 4 weeks. This work provides reassurance to stakeholders that leprosy prophylaxis can be used with OCP without any additional recommendations for contraception prevention.

Effectiveness of population-wide screening and mass drug administration for leprosy control in Kiribati: the COMBINE protocol.

INTRODUCTION: Progress towards leprosy elimination is threatened by increasing incidence in 'hot-spot' areas where more effective control strategies are urgently required. In these areas, active case finding and leprosy prevention limited to known contacts is insufficient for control. Population-wide active case-finding together with universal prevention through mass drug administration (MDA) has been shown to be effective in 'hot-spot' areas, but is logistically challenging and expensive. Combining leprosy screening and MDA with other population-wide screening activities such as for tuberculosis may increase programme efficiency. There has been limited evaluation of the feasibility and effectiveness of combined screening and MDA interventions. The COMBINE study aims to bridge this knowledge gap. METHODS AND ANALYSIS: This implementation study will assess the feasibility and effectiveness of active leprosy case-finding and treatment, combined with MDA using either single-dose rifampicin or rifamycin-containing tuberculosis preventive or curative treatment, for reducing leprosy incidence in Kiribati. The leprosy programme will run over 2022-2025 in concert with population-wide tuberculosis screening-and-treatment in South Tarawa. The primary research question is to what extent the intervention reduces the annual leprosy new case detection rate (NCDR) in adults and children compared with routine screening and postexposure prophylaxis (PEP) among close contacts (baseline leprosy control activities). Comparisons will be made with (1) the preintervention NCDR separably among adults and children in South Tarawa (before-after study) and (2) the corresponding NCDRs in the rest of the country. Additionally, the postintervention prevalence of leprosy obtained from a survey of a 'hot-spot' sub-population will be compared with prevalence documented during the intervention. The intervention will be implemented in collaboration with the Kiribati National Leprosy Programme. ETHICS AND DISSEMINATION: Approval has been obtained from the Kiribati Ministry of Health and Medical Services (MHMS), the University of Otago (H22/111) and the University of Sydney (2021/127) Human Research Ethics Committees. Findings will be shared with the MHMS, local communities and internationally through publication.

Rifampicin Allergy Leading to Acute Renal Shutdown.

Rifampicin is a widely used drug to treat tuberculosis and leprosy. Its toxicity is predominantly hepatic and immunoallergic in character. While hepatic toxicity is dose-related, the immunoallergic effects are unpredictable and usually associated with intermittent therapy. These immunoallergic effects may be minor (a cutaneous, gastrointestinal, or influenza-like syndrome) or major (hemolytic anemia, shock, or acute renal failure). Herein, we report a case of rifampicin allergy in a patient who was on intermittent once monthly rifampicin therapy for neuritic leprosy and was on his 4th month of treatment. Rifampicin exposure led to sudden shock and acute renal failure, which eventually required hemodialysis support. The patient made a complete recovery over the subsequent days and his renal function returned to normal over the next 3 weeks. He continues his multidrug therapy of leprosy without rifampicin.

Protocol, rationale and design of BE-PEOPLE (Bedaquiline enhanced exposure prophylaxis for LEprosy in the Comoros): a cluster randomized trial on effectiveness of rifampicin and bedaquiline as post-exposure prophylaxis of leprosy contacts.

BACKGROUND: Leprosy is an ancient infectious disease with an annual global incidence of around 200,000 over the past decade. Since 2018, the World Health Organization (WHO) recommends single-dose rifampicin as post-exposure prophylaxis (SDR-PEP) for contacts of leprosy patients. The Post ExpOsure Prophylaxis for Leprosy (PEOPLE) trial evaluated PEP with a double dose of rifampicin in Comoros and Madagascar. Preliminary results of this trial show some reduction in leprosy incidence in intervention villages but a stronger regimen may be beneficial. The objective of the current Bedaquiline Enhanced ExpOsure Prophylaxis for LEprosy trial (BE-PEOPLE) is to explore effectiveness of a combination of bedaquiline and rifampicin as PEP. METHODS: BE-PEOPLE is a cluster-randomized trial in which 44 clusters in Comoros will be randomized to two study arms. Door-to-door screening will be conducted annually during four years, leprosy patients identified will be offered standard of care treatment. Based on study arm, contacts aged five years and above and living within a 100-meter radius of an index case will either receive bedaquiline (400-800 mg) and rifampicin (150-600 mg) or only rifampicin (150-600 mg). Contacts aged two to four years will receive rifampicin only. Household contacts randomized to the bedaquiline plus rifampicin arm will receive a second dose four weeks later. Incidence rate ratios of leprosy comparing contacts who received either of the PEP regimens will be the primary outcome. We will monitor resistance to rifampicin and/or bedaquiline through molecular surveillance in all incident tuberculosis and leprosy patients nationwide. At the end of the study, we will assess anti-M. leprae PGL-I IgM seropositivity as a proxy for the population burden of M. leprae infection in 8 villages (17,000 individuals) that were surveyed earlier as part of the PEOPLE trial. DISCUSSION: The COLEP trial on PEP in Bangladesh documented a reduction of 57% in incidence of leprosy among contacts treated with SDR-PEP after two years, which led to the WHO recommendation of SDR-PEP. Preliminary results of the PEOPLE trial show a lesser reduction in incidence. The BE-PEOPLE trial will explore whether reinforcing SDR-PEP with bedaquiline increases effectiveness and more rapidly reduces the incidence of leprosy, compared to SDR-PEP alone. TRIAL REGISTRATION: NCT05597280. Protocol version 5.0 on 28 October 2022.

Evolution of pediatric pharmaceutical forms for treatment of Hansen's disease (leprosy).

INTRODUCTION: Leprosy is a neglected, infectious, granulomatous and chronic disease caused by the pathological agent Mycobacterium leprae. The course of the disease is more aggressive in patients under 15 years of age, but the current treatment offered worldwide consists of solid forms, by the combination of antibiotics such as rifampicin, clofazimine and dapsone. This represents results in lack of adherence in pediatric patients and drug therapy failure, although numerous formulations and technologies have already been developed. AREA COVERED: This study aims to analyze the technological evolution of the pharmaceutical treatment of leprosy, aimed at children. A review of patents around the world was conducted to look for technical and clinical aspects of formulations and devices. EXPERT OPINION: Innovative formulations for pediatric patients were classified according to the routes of administration as oral, inhalable, injectable and transdermal. The formulations were organized as alternatives for pediatric therapy, taking into account the physicochemical aspects of drugs and the physiological aspects of pediatric patients. Among the difficulties for the patented formulations to reach the market, of special note is the low stability of the physicochemical characteristics of the drugs. Optimization of formulations would favor the pediatric treatment of leprosy, aiming at therapeutic success.

An Overview of Treatment Guidelines and Methods of Synthesis of Drugs Used in Leprosy Chemotherapy.

Leprosy is a Neglected Tropical Disease (NTDs) caused by Mycobacterium leprae (M. leprae). The treatment is considered effective, however, the high dose Multidrug Therapy (MDT) for a long period and its adverse effects result in the abandonment of the treatment by patients. Indeed, antimicrobial resistance is still an obstacle that must be overcome in the treatment of leprosy. In the present article, we reviewed the WHO guidelines for the chemotherapy of leprosy and the methods of synthesis of these drugs.

Drug Resistance (Dapsone, Rifampicin, Ofloxacin) and Resistance-Related Gene Mutation Features in Leprosy Patients: A Systematic Review and Meta-Analysis.

Dapsone (DDS), Rifampicin (RIF) and Ofloxacin (OFL) are drugs recommended by the World Health Organization (WHO) for the treatment of leprosy. In the context of leprosy, resistance to these drugs occurs mainly due to mutations in the target genes (Folp1, RpoB and GyrA). It is important to monitor antimicrobial resistance in patients with leprosy. Therefore, we performed a meta-analysis of drug resistance in Mycobacterium leprae and the mutational profile of the target genes. In this paper, we limited the study period to May 2022 and searched PubMed, Web of Science (WOS), Scopus, and Embase databases for identified studies. Two independent reviewers extracted the study data. Mutation and drug-resistance rates were estimated in Stata 16.0. The results demonstrated that the drug-resistance rate was 10.18% (95% CI: 7.85-12.51). Subgroup analysis showed the highest resistance rate was in the Western Pacific region (17.05%, 95% CI:1.80 to 13.78), and it was higher after 2009 than before [(11.39%, 7.46-15.33) vs. 6.59% (3.66-9.53)]. We can conclude that the rate among new cases (7.25%, 95% CI: 4.65-9.84) was lower than the relapsed (14.26%, 95 CI%: 9.82-18.71). Mutation rates of Folp1, RpoB and GyrA were 4.40% (95% CI: 3.02-5.77), 3.66% (95% CI: 2.41-4.90) and 1.28% (95% CI: 0.87-1.71) respectively, while the rate for polygenes mutation was 1.73% (0.83-2.63). For further analysis, we used 368 drug-resistant strains as research subjects and found that codons (Ser, Pro, Ala) on RpoB, Folp1 and GyrA are the most common mutation sites in the determining region (DRDR). In addition, the most common substitution patterns of Folp1, RpoB, and GyrA are Pro→Leu, Ser→Leu, and Ala→Val. This study found that a higher proportion of patients has developed resistance to these drugs, and the rate has increased since 2009, which continue to pose a challenge to clinicians. In addition, the amino acid alterations in the sequence of the DRDR regions and the substitution patterns mentioned in the study also provide new ideas for clinical treatment options.

Global prevalence of resistance to rifampicin in Mycobacterium leprae: A meta-analysis.

OBJECTIVES: As the only bactericidal drug in multidrug therapy is rifampicin, monitoring of antimicrobial resistance is important in leprosy patients. Therefore, we conducted a meta-analysis on the resistance of Mycobacterium leprae (M. leprae) to rifampicin and estimated drug resistance in different therapeutic states and regions. METHODS: Embase, Medline, PubMed, and Web of Science were searched to identify studies between 1 January 1993 and 1 January 2022. Two independent reviewers extracted study data. Pooled cumulative incidences were computed using random-effects meta-analyses. RESULTS: We included 32 papers describing the resistance of M. leprae to rifampicin (pooled cumulative incidences, 11% [95% confidence interval {CI}, 7% to 15%]). Therapeutic states and regional distribution were obtained for subgroup analyses. A total of 51 of 1135 new cases (pooled incidence, 10% [95% CI, 5% to 16%]) and 81 of 733 relapsed cases (pooled incidence, 20% [95% CI, 13% to 27%]) had rifampicin resistance. A total of 139 participants, including 11 patients with rifampicin resistance (pooled incidence, 42% [95% CI, -21% to 105%]), were nonresponsive and intractable cases. The incidence of rifampicin resistance was highest in the Western Pacific (pooled incidence, 21% [95% CI, 13% to 29%]) and lowest in the Americas (pooled incidence, 4% [95% CI, 1% to 7%]). CONCLUSIONS: Drug resistance testing and a robust and rigorous surveillance system are recommended to detect the prevalence of drug resistance in leprosy.

Interaction of constituents of MDT regimen for leprosy with Mycobacterium leprae HSP18: impact on its structure and function.

Mycobacterium leprae, the causative organism of leprosy, harbors many antigenic proteins, and one such protein is the 18-kDa antigen. This protein belongs to the small heat shock protein family and is commonly known as HSP18. Its chaperone function plays an important role in the growth and survival of M. leprae inside infected hosts. HSP18/18-kDa antigen is often used as a diagnostic marker for determining the efficacy of multidrug therapy (MDT) in leprosy. However, whether MDT drugs (dapsone, clofazimine, and rifampicin) do interact with HSP18 and how these interactions affect its structure and chaperone function is still unclear. Here, we report evidence of HSP18-dapsone/clofazimine/rifampicin interaction and its impact on the structure and chaperone function of HSP18. These three drugs interact efficiently with HSP18 (having submicromolar binding affinity) with 1 : 1 stoichiometry. Binding of these MDT drugs to the 'α-crystallin domain' of HSP18 alters its secondary structure and tryptophan micro-environment. Furthermore, surface hydrophobicity, oligomeric size, and thermostability of the protein are reduced upon interaction with these three drugs. Eventually, all these structural alterations synergistically decrease the chaperone function of HSP18. Interestingly, the effect of rifampicin on the structure, stability, and chaperone function of this mycobacterial small heat shock protein is more pronounced than the other two MDT drugs. This reduction in the chaperone function of HSP18 may additionally abate M. leprae survivability during multidrug treatment. Altogether, this study provides a possible foundation for rational designing and development of suitable HSP18 inhibitors in the context of effective treatment of leprosy.

Preventing leprosy with retrospective active case finding combined with single-dose rifampicin for contacts in a low endemic setting: results of the Leprosy Post-Exposure Prophylaxis program in Cambodia.

Post-exposure prophylaxis (PEP) with single-dose rifampicin (SDR) reduces the risk of developing leprosy among contacts of leprosy patients. Most evidence for the feasibility of the intervention is from highly endemic settings while low-endemic areas present unique challenges including reduced awareness of the disease among the population and in the health system, and the only sporadic occurrence of cases which together make defining any type of routine process challenging. We complemented the retrospective active case finding (RACF) approach with SDR administration to eligible contacts, and piloted the intervention across 31 operational districts in Cambodia. The aim was to demonstrate the feasibility of improving early case detection and administering SDR in a low endemic setting. The intervention focused on leprosy patients diagnosed since 2011 and was implemented between October 2016 - September 2019. The "drives" approach was employed to trace contacts: a trained team systematically contacted all eligible cases in a district, traced and screened contacts, and administered SDR. A total of 555 index patients were traced by the drive team, and 10,410 contacts in their household and 5 immediate neighbor houses listed. Among these contacts, 72.0% could be screened while most others were absent on the screening day. A total of 33 new leprosy cases were diagnosed and 6189 contacts received SDR (82.6% of the screened contacts). Sixty-one contacts refused SDR administration. We conclude that integrating PEP with SDR in RACF campaigns is feasible, and that this approach is appropriate in low resource and low endemic settings. Over time, evidence on whether or not the approach reduced leprosy transmission in Cambodia, may become clear.

The nitrosamine contamination of drugs, part 3: Quantification of 4-Methyl-1-nitrosopiperazine in rifampicin capsules by LC-MS/HRMS.

Upon emergence of nitrosamines in various drugs, e.g in valsartan, metformin and ranitidine, 4-methyl-1-nitrosopiperazine (MeNP) was found in rifampicin in August 2020. Rifampicin is used, amongst others, for post-exposure prophylaxis of leprosy. The occurrence of MeNP can be explained by the synthesis, because 1-amino-4-methylpiperazine is concomitantly used with the organic oxidizing reagent isoamyl nitrite. According to a method reported by the FDA, the quantification of MeNP in rifampicin capsules was performed by LC-MS/HRMS. A significant contamination with MeNP was found in all samples, ranging from 0.7 to 5.1 ppm and exceeding the acceptable intake limit proposed by the FDA up to 32-fold. However, the severity of a possible leprosy infection outweighs the risks, which are concomitant with the intake of a single dose of rifampicin for post-exposure prophylaxis. Nevertheless, the extent of contamination is alarming, and countermeasures are needed to minimize public health risks. The presence of nitrosamines in rifampicin illustrates the need for better strategies in impurity profiling and compendial testing once again.

Experimental Solubility, Thermodynamic/Computational Validations, and GastroPlus-Based In Silico Prediction for Subcutaneous Delivery of Rifampicin.

We focused to explore a suitable solvent for rifampicin (RIF) recommended for subcutaneous (sub-Q) delivery [ethylene glycol (EG), propylene glycol (PG), tween 20, polyethylene glycol-400 (PEG400), oleic acid (OA), N-methyl-2-pyrrolidone (NMP), cremophor-EL (CEL), ethyl oleate (EO), methanol, and glycerol] followed by computational validations and in-silico prediction using GastroPlus. The experimental solubility was conducted over temperature ranges T = 298.2-318.2 K) and fixed pressure (p = 0.1 MPa) followed by validation employing computational models (Apelblat, and van't Hoff). Moreover, the HSPiP solubility software provided the Hansen solubility parameters. At T = 318.2K, the estimated maximum solubility (in term of mole fraction) values of the drug were in order of NMP (11.9 × 10-2) ˃ methanol (6.8 × 10-2) ˃ PEG400 (4.8 × 10-2) ˃ tween 20 (3.4 × 10-2). The drug dissolution was endothermic process and entropy driven as evident from "apparent thermodynamic analysis". The activity coefficients confirmed facilitated RIF-NMP interactions for increased solubility among them. Eventually, GastroPlus predicted the impact of critical input parameters on major pharmacokinetics responses after sub-Q delivery as compared to oral delivery. Thus, NMP may be the best solvent for sub-Q delivery of RIF to treat skin tuberculosis (local and systemic) and cutaneous related disease at explored concentration.

Adverse effects of polychemotherapy for leprosy in 13 years of follow-up at a university hospital

Abstract Leprosy is one of the neglected diseases in the world and Brazil is the second country with more cases. A retrospective study was conducted based on the medical records of 196 leprosy patients diagnosed during the course of 13 years at a university hospital. The aim was to describe the adverse effects of polychemotherapy, as well the most prevalent and most vulnerable populations. In the study, dapsone was the most implicated drug, especially in women, and the risk increased with age. The authors conclude that with this patient profile, greater vigilance should be taken regarding possible adverse effects, especially anemia.