Preparation of Gentamicin Sulfate Nanoparticles using Eudragit RS-100 and Evaluation of Their Physicochemical Properties

Improving permeability and absorption of drugs are critical research challenges in pharmaceutical science. Gentamicin sulfate is an aminoglycoside antibiotic, which is very active against gram-negative bacteria; however, it has very poor bioavailability. This study aimed to prepare gentamicin nanoparticles with the intention of increased bioavailability. Accordingly, Eudragit RS-100 nanoparticles loaded with gentamicin sulfate were prepared by the double emulsification and solvent evaporation method, a proper technique for encapsulating hydrophilic molecules. Nanoparticles’ suspensions with polymer to drug ratios of 1:1 ([Formula: see text] and 2:1 ([Formula: see text]) were prepared, lyophilized and evaluated for their production yield, physicochemical properties and morphology. The mean particle size was 195.67[Formula: see text]nm and 228[Formula: see text]nm for [Formula: see text] and [Formula: see text], respectively. The formulations’ loading efficiencies were relatively high (85.73 for [Formula: see text] and 85.20 for [Formula: see text]). The nanoparticles’ surface charge (+40.5[Formula: see text]mV) was sufficient to inhibit their aggregation and facilitate the nanoparticles’ absorption through the gastrointestinal tract. The results of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) revealed that drug and polymer stabilized each other by physical interactions between their functional groups. Both formulations presented an initial burst drug release of nearly 20% after 30[Formula: see text]min in phosphate buffer (pH = 7.4). After 24[Formula: see text]h, [Formula: see text] did not release the drug completely, while [Formula: see text] released the whole drug. Overall, nanoparticles with proper characteristics were obtained. This study puts forward the necessity of conducting further research in order to explore the intestinal absorption of these nanoparticles and the possibility of being utilized for oral administration of gentamicin sulfate.

Exploring two distinct gentamicin prescribing protocols in UK hospitals: a mixed-methods realist evaluation

ObjectivesGentamicin is the aminoglycoside antibiotic of choice in the UK. It has a narrow therapeutic index: underdosing results in inefficacy while overdosing is characterised by nephrotoxicity and ototoxicity. To improve patient safety, hospitals have protocols for the prescription of gentamicin, which vary in complexity and approach. This study aimed to explore two distinct protocols for prescribing gentamicin in hospital settings, in order to understand the mechanisms they trigger and the outcomes they achieve.SettingA mixed-methods realist evaluation explored gentamicin prescribing protocols in two hospital surgical admissions units in South West England between January and August 2018. Site 1 had a traditional, complex protocol, while site 2 took a simplified protocol.ParticipantsTesting the initial programme theory (IPT) involved semi-structured audio-recorded interviews of a volunteer sample of healthcare professionals (HCPs) involved in the prescribing and administering process, alongside a clinical audit reviewing accuracy of gentamicin prescribing.Outcome measuresThree sequential phases were used to identify factors in a successful protocol: IPT generation; testing; refinement of the IPT. The IPT was generated by literature search and analysis of existing protocols of sites 1 and 2. Refinement of the IPT synthesised the results of the quantitative and qualitative research to identify the key characteristics of a successful protocol.ResultsOne hundred gentamicin prescriptions were reviewed, with a mean accuracy of gentamicin prescribing at site 1 of 65.67% and at site 2 of 78.79% (p<0.01). Thirty HCPs were interviewed. Key contexts were identified including prescriptiveness, experience and availability of patient information. These triggered hidden mechanisms including uncertainty, fear, confidence and frustration leading to both intended outcomes but also unintended outcomes such as deviation from protocol and unnecessary gentamicin levels.ConclusionsA simplified prescribing protocol for gentamicin is better accepted by prescribers, leading to better adherence to protocol and more accurate prescribing.

Microbiological Antibiotic Assay Validation of Gentamicin Sulfate Using Two-Dose Parallel Line Model (PLM)

Till nowadays microbiological assay is still widely used with several antibiotics that are composed of a mixture of related active compounds. However, obtaining a reasonably valid determination of the potency is dependent on the validity and the suitability of the assay design. The present work aimed to validate an assay design of an aminoglycoside antibiotic (Gentamicin Sulfate) using a two-dose Parallel Line Model agar diffusion assay in a large 8×8 rectangular plate. All preparatory procedures were done following United States Pharmacopeia and the Inhibition Zones were measured using a digital caliper to the nearest 0.01 mm. Analysis of variance of compendial requirements of regression and parallelism were found to be satisfactorily meeting the acceptance criteria. Specificity was achieved for the product under investigation with no detectable IZ that could be found for all components except the antibiotic. The validation method showed acceptable linearity of r2≥0.98. Accuracy and precision parameters showed RSD (%)<2. All relative error value estimates were below 4%. The proposed validation design for 32×32 cm antibiotic plates yielded valid results and can be projected for the routine Quality Control analysis of the antibiotic material, especially which is incorporated into a finished medicinal dosage form. Doi: 10.28991/HIJ-2021-02-04-04 Full Text: PDF

Multicenter Clinical Evaluation Of For Susceptibility Testing Of Enterobacterales

Plazomicin (PLZ), brand name ZEMDRI (Cipla Therapeutics), is a novel aminoglycoside antibiotic approved by the US Food and Drug Administration (FDA) for treatment of complicated urinary tract infections including pyelonephritis. ETEST® is a gradient diffusion method that represents an alternative to the more laborious broth micro-dilution (BMD) method for performing antimicrobial susceptibility testing (AST). A multi-center evaluation of the performance of the new ETEST® PLZ (bioMérieux) was conducted in comparison with BMD following FDA and International Standards Organization (ISO) recommendations using FDA-defined breakpoints. Clinical isolates of Enterobacterales (n=598) were included. Fifty-three isolates were resistant to PLZ according to BMD. Overall, the ETEST® PLZ demonstrated 99.0% Essential Agreement (EA), 92.8% Category Agreement (CA), 1.9% Very Major Errors (VME), 0% Major Errors (ME) and 7.0% minor Errors (mE) with both clinical and challenge isolates of Enterobacterales. The VME was found for a single Serratia marcescens strain. Individual species demonstrated EA rates ≥ 90%. In conclusion, we report that ETEST® PLZ represents an accurate tool for performing PLZ AST of Enterobacterales.

Characterization of Methyltransferase from Apramycin Biosynthetic Gene Cluster and Improvement Production of Apramycin in Engineered Streptoalloteichus Tenebrarius

BackgroundApramycin is a structurally unique aminoglycoside, used in veterinary medicine or the treatment of Salmonella, Escherichia coli and Pasteurella multocida infections in farm. Although discovered and used many years ago, many biosynthetic steps of apramycin are still obscure. ResultsIn this study, we identified a HemK family methyltransferase, aprI, involved in apramycin biosynthesis. The function of aprI was studied by using gene disruption and biochemical experiments, and a new aminoglycoside antibiotic demethyl-apramycin was purified from aprI disruption strain. Experiments proved that AprI converted demethyl-aprosamine to aprosamine in vitro. Based on this, the apramycin production strain was improved by overexpression the AprI to decrease the impurity production. ConclusionsWe have identified aprI is a 7’-N-methyltransferase gene in apramycin biosynthesis and confirmed the substrate of methyltransferase. Engineering of aprI resulted in a strain producing a new aminoglycoside demethyl-apramycin and apramycin mono-producing strain with less impurity production. Finally, the yield of demethyl-apramycin in apramycin mono-producing strain decreased from 196±36 mg/L to 51±9 mg/L, and the yield of apramycin increased from 2227±320 mg/L to 2331±210 mg/L.

The Ganglioside Monosialotetrahexosylganglioside Protects Auditory Hair Cells Against Neomycin-Induced Cytotoxicity Through Mitochondrial Antioxidation: An in vitro Study

Neomycin is a common ototoxic aminoglycoside antibiotic that causes sensory hearing disorders worldwide, and monosialotetrahexosylganglioside (GM1) is reported to have antioxidant effects that protect various cells. However, little is known about the effect of GM1 on neomycin-induced hair cell (HC) ototoxic damage and related mechanism. In this study, cochlear HC-like HEI-OC-1 cells along with whole-organ explant cultures were used to establish an in vitro neomycin-induced HC damage model, and then the apoptosis rate, the balance of oxidative and antioxidant gene expression, reactive oxygen species (ROS) levels and mitochondrial membrane potential (MMP) were measured. GM1 could maintain the balance of oxidative and antioxidant gene expression, inhibit the accumulation of ROS and proapoptotic gene expression, promoted antioxidant gene expression, and reduce apoptosis after neomycin exposure in HEI-OC-1 cells and cultured cochlear HCs. These results suggested that GM1 could reduce ROS aggregation, maintain mitochondrial function, and improve HC viability in the presence of neomycin, possibly through mitochondrial antioxidation. Hence, GM1 may have potential clinical value in protecting against aminoglycoside-induced HC injury.

Experimental confirmation that an uncommon, yet clinically relevant mutation (G878A) in the rrs gene of Mycobacterium tuberculosis confers resistance to streptomycin.

The effective treatment of patients diagnosed with drug resistant tuberculosis (TB) is highly dependent upon the ability to rapidly and accurately determine the antibiotic resistance/ susceptibility profile of the Mycobacterium tuberculosis isolate(s) involved. Thus, as more and more clinical microbiology laboratories advance towards the routine use of DNA sequence-based diagnostics, it is imperative that their predictive functions extend beyond the well-known resistance-conferring mutations, in order to also encompass as many of the lower-frequency mutations as possible. However, in most cases, the fundamental experimental proof that links these uncommon mutations with phenotypic resistance is still lacking. One such example is the G878A polymorphism within the rrs gene encoding the 16s rRNA. We, and others, have identified this mutation within a small number of drug-resistant M. tuberculosis isolates, although prior to this study a consensus regarding exactly which aminoglycoside antibiotic(s) it conferred resistance toward seems not to have been reached. Here we have employed oligo-mediated recombineering to specifically introduce the G878A polymorphism into the rrs gene of M. bovis BCG - a species very closely related to M. tuberculosis - and demonstrate that it confers low-level resistance to streptomycin alone. In our hands, it does not confer cross-resistance towards amikacin, capreomycin, nor kanamycin. We also demonstrate that the rrsG878A mutation exerts a substantial fitness defect in vitro, that may at least in part explain why clinical M. tuberculosis isolates bearing this mutation appear to be quite rare. Overall, this study provides clarity to the resistance phenotype attributable to the rrsG878A mutation and is relevant to the future implementation of genomics-based diagnostics, as well as the clinical management of patients in situations where this particular polymorphism is encountered.

Prophylaxis With Diosmin Mitigates Kidney Damage Induced by Gentamicin in Rats

Background Gentamicin is a crucial aminoglycoside antibiotic but it is used only to treat severe bacterial infections, because of its high nephrotoxicity among patients. We evaluated the preventive effects of diosmin (as a natural ingredient) on gentamicin-related renal damage in rats. MethodsIn this research, 28 male Wistar rats were assigned to 4 groups: control, gentamicin (100 mg/kg, (i.p.), daily for 1 week), and gentamicin plus diosmin (50mg/kg, p.o., daily for two weeks), diosmin (50mg/kg/day, p.o. for two weeks). After, the final gavage, blood specimens were gathered for determining serum blood urea nitrogen (BUN) and creatinine. kidneys used for biochemical, inflammation and histological test.Results Creatinine, BUN, nitric oxide, malondialdehyde, TNF-α and IL-1β concentrations significantly increased and glutathione, catalase, glutathione peroxidase, and superoxide dismutase activities decreased after gentamicin treatment. Creatinine, BUN, nitric oxide, malondialdehyde, tumour necrosis factor α (TNF-α), interleukin 1 beta (IL-1β) concentrations significantly reduced and glutathione level, catalase and glutathione peroxidase activities significantly increased via co-administration with diosmin. ConclusionDiosmin had ameliorative impacts against gentamicin-related kidney injury that can be owing to its antioxidant, and anti-inflammatory activities.