Neomycin 0.25% / Gramicidin 0.025% ointment

Devastating or nearly invariably fatal infections caused by free-living amoebae (FLA), including Acanthamoeba keratitis (AK), granulomatous amoebic encephalitis (GAE), and primary amoebic meningoencephalitis (PAM), remain a significant public health concern, driven by increasing case numbers, geographic expansion, and the lack of approved, effective, and safe treatments. Despite decades of research, no new drugs have been successfully approved, highlighting the severe limitations of de novo drug development for these infections, particularly for GAE and PAM, largely due to the challenges of conducting clinical trials for these rare and rapidly lethal diseases. In this context, drug repurposing represents a cost-effective and promising strategy to accelerate therapeutic advances and overcome key bottlenecks of conventional drug development. Accordingly, we conducted a systematic review of in vitro studies and animal models of AK, GAE, and PAM reported in indexed databases to identify promising drug repurposing candidates against FLA infections. After screening 23,624 records, 112 studies were included in the analysis. Overall, 2726 drugs and drug combinations, spanning 865 pharmacological classes and approved for 565 therapeutic indications, were assessed for their repurposing potential. Among these, 166 compounds showed substantial trophocidal activity (≥IC50) at potentially translatable concentrations (≤10 µM), including six with additional cysticidal activity. In vitro, four compounds were active against Balamuthia mandrillaris, 44 against Acanthamoeba spp. (three cysticidal), and 115 against Naegleria spp. (three cysticidal). In in vivo studies, sulfadiazine and rifampicin were effective as preventive or early monotherapies for GAE. For AK, the combination of polyhexamethylene biguanide, neomycin, and atropine, as well as voriconazole and nitazoxanide monotherapies, showed the greatest promise. In PAM, azithromycin alone or in combination with amphotericin B emerged as the most promising therapeutic options. Further studies are required to advance the clinical translatability of these findings. To the best of our knowledge, this work provides the first comprehensive and integrated synthesis of repurposable drug candidates against FLA infections.

Abstract licence: CC BY

Background: Topical steroids are used widely to manage excessive inflammation and hypergranulation in burns; however, their use is controversial, and current evidence is largely anecdotal. Topical KENACOMB is a steroid preparation consisting of triamcinolone acetonide, neomycin, gramicidin, and nystatin, and it is standard of care at the Royal Brisbane and Women's Hospital burns unit. To our knowledge, there is no published literature that reports the use of KENACOMB to treat wound-associated inflammation and hypergranulation. Objective: To synthesise current evidence surrounding the efficacy and safety of topical steroid use in treating inflammation and hypergranulation in burns patients. We also describe the use of topical KENACOMB in our burns unit. Methods: A systematic review of PubMed, Cochrane, and EMBASE databases was performed. Articles published in English that reported the use of topical steroids for granulation tissue or inflammation in burn wounds or skin graft donor sites were included. Results: We identified 350 articles, of which six met inclusion criteria. Four studies presented primary patient data, and two studies reported the results of surveys of burns unit professionals. A total of 54 patients were included across all studies, and no control group was reported in any study. Studies reported rapid improvements in healing, with 86.6%-100% of wounds showing complete reepithelialisation following treatment. Reported adverse outcomes included skin thinning, atrophy of granulation tissue, systemic side effects, and local wound infection. Conclusions: This review highlights the paucity of conclusive evidence on the outcomes of topical steroids in treating inflammation and hypergranulation in burns and donor sites. While KENACOMB has shown efficacy in treating these wound types in our local experience, there is limited research available on the product. There is a clear need for quality research on the use of topical steroids in burns patients to better inform its ongoing clinical use.

Abstract licence: CC BY-NC-ND

Using free microorganisms for industrial processes has some limitations, such as the extensive consumption of substrates for growth, significant sensitivity to the microenvironment, and the necessity of separation from the product and, therefore, the cyclic process. It is widely acknowledged that confining or immobilizing cells in a matrix or support structure enhances enzyme stability, facilitates recycling, enhances rheological resilience, lowers bioprocess costs, and serves as a fundamental prerequisite for large-scale applications. This report summarizes the various cell immobilization methods, including several synthetic (polyvinylalcohol, polyethylenimine, polyacrylates, and Eudragit) and natural (gelatin, chitosan, alginate, cellulose, agar-agar, carboxymethylcellulose, and other polysaccharides) polymeric materials in the form of thin films, hydrogels, and cryogels. Advancements in the production of well-known antibiotics like penicillin and cephalosporin by various strains were discussed. Additionally, we highlighted cutting-edge research related to strain producers of peptide-based antibiotics (polymyxin B, Subtilin, Tyrothricin, varigomycin, gramicidin S, friulimicin, and bacteriocin), glusoseamines, and polyene derivatives. Crosslinking agents, especially covalent linkers, significantly affect the activity and stability of biocatalysts (penicillin G acylase, penicillinase, deacetoxycephalosporinase, L-asparaginase, β-glucosidase, Xylanase, and urease). The molecular weight of polymers is an important parameter influencing oxygen and nutrient diffusion, the kinetics of hydrogel formation, rigidity, rheology, elastic moduli, and other mechanical properties crucial for long-term utilization. A comparison of stability and enzymatic activity between immobilized enzymes and their free native counterparts was explored. The discussion was not limited to recent advancements in the biopharmaceutical field, such as microorganism or enzyme immobilization, but also extended to methods used in sensor and biosensor applications. In this study, we present data on the advantages of cell and enzyme immobilization over microorganism (bacteria and fungi) suspension states to produce various bioproducts and metabolites-such as antibiotics, enzymes, and precursors-and determine the efficiency of immobilization processes and the optimal conditions and process parameters to maximize the yield of the target products.

Abstract licence: CC BY

Aim/Background To develop and validate a sensitive, accurate, simple, precise and cost-effective receptive and understandable method for concurrent evaluation of Gramicidin, Neomycin and Triamcinolone acetonide and their related contaminants via UPLC. Materials and Methods This method includes the separation using a chromatographic Phenyl column (50 mmx2.1 mm, 1.7 µm). A portable stage of 0.1% TEA (Tri-Ethylamine) and acetonitrile in gradient elution mode with 0.5mL/Temperature and minimum flow rate were employed. At 230 nm, UV observations were made. The limitations for Linearity, quantification and recoveries were discovered being within the allowable range. With UPLC, this method was successfully tested and ICH Q2 (R1) recommendations. Results Gramicidin, Neomycin and Triamcinolone acetonide retention times were observed at 9.315 min,3.979 min and 1.697 min respectively. A gradient elution of Triamcinolone acetonide, Neomycin and Gramicidin involves phenyl column that flows from 0.5 mL/min and the column internal temperature were held constant. Mobile phase % TEA likewise acetonitrile was utilised. UV monitoring was brought at 230 nm. Conclusion This study created an entirely new, straightforward, quick, affordable, sensitive and easily accessible UPLC method for the coincident determination of Triamcinolone acetonide, Neomycin and Gramicidin bulky and ointment dose form. This method has the benefits of being less expensive, assessible, reliable, sensitive and reproducible. Under conditions of oxidation, (Neutral, basic and acidic) hydrolysis, photolysis, thermal stress and medicines degradative activities were investigated. The medications were discovered to be solid underheat, unstable, hydrolysis under acid, alkaline and oxidative circumstances. The Final application of the UPLC method to the commercial formulations followed the ICH recommendations.

Abstract licence: CC BY

The dosage form iotrim (gramicidin, neomycin and triamcinolone) is a combination of two antibiotics (gramicidin and neomycin) and a steroid (triamcinolone). The antibiotics work by killing the bacteria that cause infections. The steroid blocks the action of chemical messengers (prostaglandins) that make the affected area red, swollen and itchy. Consequently, there was still a need to develop a simple, less time consuming and economical method for the simultaneous determination of gramicidin, neomycin and triamcinolone acetonide. The current work is an effort to develop a fast and reproducible LC-MS technique for the simultaneous estimation of gramicidin, neomycin and triamcinolone acetonide. The objective of the present procedure was to validate and develop a precise and accurate liquid chromatography-mass spectrometry (LC-MS) technique for the simultaneous quantification of gramicidin, neomycin and triamcinolone acetonide. Gramicidin, neomycin and triamcinolone acetonide were monitored on Shimadzu-8045 mass spectrometer equipped with electro spray ionization interface. The retention times of gramicidin, neomycin and triamcinolone acetonide were found at 9.145 min, 7.273 min and 2.435 min, respectively. The limit of detection (LOD) results for gramicidin, neomycin and triamcinolone acetonide were observed to be 0.15, 1.5 and 0.6 μg/mL, respectively while the limit of quantification (LOQ) results were observed to be 0.5, 5, 2 μg/mL concentration, respectively. The linear range for gramicidin, neomycin and triamcinolone acetonide were found in the concentration ranges from 1.25-7.5 μg/mL, 12.5-75 μg/mL and 5-30 μg/mL with regression coefficient of 0.9991, 0.9996, 0.9999, respectively. Accuracy values for gramicidin, neomycin and triamcinolone acetonide were found to be in the range of 98.64%, 99.4%, 99.5% respectively. The % RSD for six replicates in precision was less than 2%. According to ICH Q2(R1) recommendations, this method was successfully tested with LC-MS to confirm the chemical structures of newly produced degradation products of triamcinolone acetonide and neomycin. The developed process was validated efficaciously as per ICH guidelines.

Abstract licence: CC BY

INTRODUCTION: Antimicrobial resistance (AMR) is a global issue that needs addressing. While antibiotic stewardship has improved often by restricting antibiotic use, some antibiotics that are still sold legally over the counter (OTC), notably in sore throat medications. Recent findings suggest OTC antibiotics could trigger cross-resistance to antibiotics used in clinical treatments, whether systemic or topical. Here we investigated the impact of three antibiotics contained in OTC sore throat medicines on emerging AMR in vitro. METHODS: Bacterial pathogens were exposed to a bactericidal concentration of an aminoglycoside in the presence or absence of a during-use concentration of bacitracin, gramicidin or tyrothricin in a time-kill assay. Damage to the bacterial membrane was also investigated by measuring potassium leakage and membrane potential alteration post-OTC antibiotic exposure. RESULTS: Gramicidin (15 µg/mL) significantly decreased the bactericidal activity of amikacin, tobramycin or gentamicin in Acinetobacter baumannii. It also decreased gentamicin bactericidal activity in Enterobacter cloacae, Escherichia coli and Klebsiella pneumoniae, while tyrothricin decreased the aminoglycoside efficacy in E. cloacae and E. coli. Gramicidin significantly decreased bacterial membrane potential and caused significant potassium leakage. CONCLUSION: Gramicidin and to some extent tyrothricin impacted aminoglycoside efficacy by affecting membrane potential, which is essential for aminoglycosides uptake. Thus, some OTC antibiotics can interfere with aminoglycoside activity, which could in turn affect treatment efficacy. Although the likelihood of OTC antibiotics and aminoglycosides being used at the same time might not be common, this research highlights one potential reason for OTC antibiotics' usage to result in treatment failure and their contribution to AMR development.

Abstract licence: CC BY-NC

Currently, Gramicidin S (GR-S) is produced enzymatically with the drawback of the presence of trifluoroacetic acid (TFA) or produced by fermentation involving several separation and purification steps. Therefore, this study is focused on the use of green solvents as unique extraction step to produce Gramicidin S from microbial biomass of Aneurinibacillus aneurinilyticus. Among the tested solvents, such as ethanol, acidic ethanol or buffer phosphate, the most favorable was acidic ethanol, extracting 96% of Gramicidin S from cells with a purity of 90%. Using acidic ethanol, extraction time within the range of 30–120 min exhibited minimal impact on Gramicidin S yield, whereas the biomass-to-extractant ratio emerged as a critical parameter. Gramicidin S extracts were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS), and Electrospray Ionization Mass Spectrometry (ESI-MS) coupled with Ultra Performance Liquid Chromatography (UPLC) and compared with commercial Gramicidin S.

Abstract licence: CC BY