Are antibiotics substandard in Lebanon? Quantification of active pharmaceutical ingredients between brand and generics of selected antibiotics.

BACKGROUND: In developing countries, brand-generic substitution is not based on validated scientific evidence that confirm the therapeutic equivalence of the generic to the originator. Rather, decisions are made based on the availability of generic medications. Substitution by inappropriate preparations applies to antibiotics, which may increase the risk of resistance in case of underdosing. This analytical study aims to dose and assess for the accuracy of labeling three oral antibiotic preparations, namely ciprofloxacin hydrochloride, amoxicillin trihydrate and amoxicillin trihydrate-clavulanate potassium, the active pharmaceutical ingredients (APIs) found in brand and generic tablets available on the Lebanese market. METHODS: One brand and 4 generics of ciprofloxacin tablets, 3 generic amoxicillin tablets, and 1 brand and 4 generics of amoxicillin-clavulanic acid medications, were quantified, taking 2 batches of each. According to the United States Pharmacopeia (USP) guidelines, ultra-high pressure liquid chromatography was used to measure the APIs content within tablets. The USP required assay limit of the API was taken as the main comparison criteria. RESULTS: Out of the 5 ciprofloxacin medications tested, all 5 were out of the 2% required range, thus being substandard. For amoxicillin, all 3 medications were within the 20% range. As for amoxicillin-clavulanic acid medications, 4 out of 5 medications met the 30% required range of clavulanic acid and one exceeded the claimed amount of clavulanic acid, while all 5 met the assay limit for amoxicillin. CONCLUSION: These findings raise safety and efficacy concerns, providing solid grounds for potential correlations of antibiotic resistance/substandard antibiotics.

New library of pyrazole-imidazo[1,2-α]pyridine molecular conjugates: Synthesis, antibacterial activity and molecular docking studies.

A library of novel pyrazole-imidazo[1,2-α]pyridine scaffolds was designed and synthesized through a one-pot three-component tandem reaction. The structures of synthesized conjugates were confirmed by spectroscopic techniques (NMR, IR and HRMS). In vitro antibacterial evaluation of the twelve synthesized molecules (7a, 8a-k) against methicillin-resistant Staphylococcus aureus and normal strains of Escherichia coli, Salmonella typhimurium, Klebsiella pneumonia and Pseudomonas aeruginosa established 8b, 8d, 8e, 8h and 8i as potent antibacterial agents with superior minimum bactericidal concentration, compared with standard drug ciprofloxacin. Molecular docking studies of all active compounds into the binding site of glucosamine-6-phosphate synthase were further performed in order to have a comprehensive understanding of putative binding modes within the active sites of the receptor.

Development of certified reference materials for accurate determination of fluoroquinolone antibiotics in chicken meat.

Certified reference materials (CRMs; KRISS CRM 108-03-003, 108-03-004) were developed for the accurate determination of fluoroquinolones (enrofloxacin and ciprofloxacin, respectively) in chicken meat. Two groups of chickens were cured with feeds containing enrofloxacin and ciprofloxacin, respectively. After slaughter, the thigh and breast meats were combined for the respective groups and the meat was freeze-dried, pulverized, sieved, and V-mixed. The final bulk material was bottled in 10g portions. For certification of the CRMs, isotope dilution-liquid chromatography/tandem mass spectrometry was used. The certified values of the CRMs were (19.06±0.86)mg/kg for enrofloxacin and (1.095±0.038)mg/kg for ciprofloxacin. The stabilities of the CRMs were monitored at -70°C for 12months, at -20°C for 2months, and at room temperature for 1month. Both CRM candidates were stable during the monitoring period for each temperature.

Development of a microparticle-based dry powder inhalation formulation of ciprofloxacin hydrochloride applying the quality by design approach.

Pulmonary drug delivery of ciprofloxacin hydrochloride offers effective local antibacterial activity and convenience of easy application. Spray drying is a trustworthy technique for the production of ciprofloxacin hydrochloride microparticles. Quality by design (QbD), an up-to-date regulatory-based quality management method, was used to predict the final quality of the product. According to the QbD-based theoretical preliminary parameter ranking and priority classification, dry powder inhalation formulation tests were successfully performed in practice. When focusing on the critical parameters, the practical development was more effective and was in correlation with our previous findings. Spray drying produced spherical microparticles. The dry powder formulations prepared were examined by particle size analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray powder diffraction, differential scanning calorimetry, and in vitro drug release and aerodynamic particle size analyses were also performed. These formulations showed an appropriate particle size ranging between 2 and 4 µm and displayed an enhanced aerosol performance with fine particle fraction up to 80%.

Quality-by-Design II: Application of Quantitative Risk Analysis to the Formulation of Ciprofloxacin Tablets.

Qualitative risk assessment methods are often used as the first step to determining design space boundaries; however, quantitative assessments of risk with respect to the design space, i.e., calculating the probability of failure for a given severity, are needed to fully characterize design space boundaries. Quantitative risk assessment methods in design and operational spaces are a significant aid to evaluating proposed design space boundaries. The goal of this paper is to demonstrate a relatively simple strategy for design space definition using a simplified Bayesian Monte Carlo simulation. This paper builds on a previous paper that used failure mode and effects analysis (FMEA) qualitative risk assessment and Plackett-Burman design of experiments to identity the critical quality attributes. The results show that the sequential use of qualitative and quantitative risk assessments can focus the design of experiments on a reduced set of critical material and process parameters that determine a robust design space under conditions of limited laboratory experimentation. This approach provides a strategy by which the degree of risk associated with each known parameter can be calculated and allocates resources in a manner that manages risk to an acceptable level.

Quality of Antimicrobial Products Used in Striped Catfish (Pangasianodon hypophthalmus) Aquaculture in Vietnam.

Antimicrobial usage is common in Asian aquaculture. This study aimed to determine the quality of antimicrobial products used by Vietnamese striped catfish (Pangasianodon hypophthalmus) farmers. Twenty one antimicrobial products (11 products contained a single antimicrobial and 10 products contained a mixture of two different antimicrobials) commonly used by catfish farmers were obtained from so-called chemical shops located in the Mekong Delta, Vietnam. Ultra High Performance Liquid Chromatography Mass Spectrometry was used to analyze concentration of sulfonamides, trimethoprim, amoxicillin, cefalexin and ciprofloxacin whereas concentrations of florfenicol and doxycycline were analyzed by High Performance Liquid Chromatography with UV detection. Results revealed that only 4/11 products with a single antimicrobial and 2/10 products with a mixture of antimicrobials contained active substances within ±10% of the concentration declared on the product label. Two products with antimicrobial mixtures did not contain any of the declared antimicrobials. Comparing two batches, analysis of 11 products revealed that only one product contained a concentration of active compound that varied with less than 10% in both batches. Several product labels provided inadequate information on how to calculate therapeutic dosage and further stated withdrawal time despite lack of pharmacokinetic data on the antimicrobials in catfish. There is an urgent need to strengthen approval procedures and in particular regularly to monitor the quality of antimicrobials used in Vietnamese aquaculture.

Shelf-life extension program (SLEP) as a significant contributor to Strategic National Stockpile Maintenance: the Israeli experience with ciprofloxacin.

In the past decade, the 2001 anthrax incident in the U.S. and the 2003 SARS epidemic have highlighted the biological threat to civilian populations. The risk posed by the natural or manmade spread of biological agents among the population dictates a need for better national preparedness. One key component of this preparation is the establishment of a Strategic National Stockpile (SNS) of pharmaceuticals that would provide appropriate medical countermeasures in case of an outbreak. However, to reduce the expense of such a stockpile and to make it worthwhile, there is also a need for a shelf-life extension program (SLEP) through which pharmaceuticals could be extended beyond manufacturer-ascribed shelf life, as long as they meet regulation standards. In this article, we review the Israeli experience with the national ciprofloxacin stockpile procurement and shelf-life extension program.

Development of an ultrasonic slurry sampling method for the determination of Cu and Mn in antibiotic tablets by electrothermal atomic absorption spectrometry.

A new method is described for simple, efficient and rapid determination of Cu and Mn in tablets of antibiotics (ciprofloxacin and cephalexin) by electrothermal atomic absorption spectrometry (ETAAS) using slurry sampling. In order to optimize the procedure, several variables that could affect the performance of the method were investigated. In the best conditions, the tablets could be analyzed by introducing into the graphite tube 20 µl of a slurry prepared with approximately 90-100mg of the sample and 2 ml of a solution containing 5% m/v of Triton X-114 and 2.8 M of HNO(3). Before the introduction, the slurries were sonicated for 15 min at 40% of amplitude (130 W maximum power) with an ultrasonic probe. The developed method was applied in the determination of Cu and Mn in four samples, and the results were compared with those obtained by focused microwave acid digestion with aqua regia (1:3 mixture of HNO(3):HCl). There was no statistical difference between the obtained values at 95% confidence level when a paired Student t-test was applied.

The need for better data about counterfeit drugs in developing countries: a proposed standard research methodology tested in Chennai, India.

WHAT IS KNOWN AND OBJECTIVE: There is still surprisingly little basic research data to support widely repeated claims about the prevalence of drug counterfeiting. To meet the need for more reliable drug quality data, we designed a study framework that includes clear definitions of measured end points, sampling methods and assay technique. Our objective was to test this research design in Chennai (formerly Madras), India, using a joint Indian and Canadian team. METHODS: The city was divided into ten areas along municipal lines. From each area, ten stores and pharmacies selling drugs were selected. At each of these 100 outlets, three study drugs (artesunate, ciprofloxacin and rifampicin) were purchased. The 300 samples were tested by Liquid Chromatography-Mass Spectrometry. Assay content was expressed as a percentage of stated tablet content. Based on assay results and their distribution, we developed drug quality definitions for normal manufacturing standards, counterfeiting, decomposition, poor quality control and adulteration. RESULTS: The group mean for ciprofloxacin was close to normal manufacturing limits (99·2 ± 7·1%) but rifampicin (91·6 ± 5·7%), and artesunate (80·1 ± 9·1%), were both below normal pharmaceutical standards. Overall, 43% of all samples fell below the widely accepted manufacturing range of 90-110% of stated content. No tablet from any sample contained less than 50% of the stated dose. WHAT IS NEW AND CONCLUSION: The quality of at least some anti-infective drugs in Chennai is below commonly accepted standards but we found no evidence of criminal counterfeiting. Poor drug quality was most likely due to decomposition during storage or poor manufacturing standards. Our research methodology worked well under practical conditions and should hopefully be of value to others working in this area.

CFC: uma alternativa para as infecções endodônticas resistentes? / CFC: an alternative to endodontic refractory infecctions?

O objetivo deste trabalho foi testar a efetividade antimicrobiana do hidróxido de cálcio, metronidazol e ciprofloxacina, quando utilizados isolados ou em associações sobre o Enterococcus faecalis. Uma colônia de Enterococcus faecalis ATCC 29212 foi cultivada e, após o desenvolvimento, os microrganismos foram removidos e inoculados em infusão de Mueller-Hinton. As placas foram divididas em quatro partes e ao centro de cada divisão foi realizado um poço para a colocação das medicações. A ciprofloxacina isolada foi a medicação mais efetiva. Considerando as associações, todas promoveram inibição, sem diferenças estatisticamente significativas. O hidróxido de cálcio e metronidazol isolados.

Bioequivalence evaluation of 320 mg gemifloxacin tablets in healthy volunteers.

This study was done to compare the bioavailability of a new tablet formulation of gemifloxacin (gemifloxacin 320 mg/tablet) with that of the reference product (factive 320 mg/tablet). The bioequivalence of a single dose (320 mg) was assessed for gemifloxacin included in the test and reference products by comparing the pharmacokinetic parameters derived from the plasma concentration-time profiles following administration to 24 healthy male volunteers in a balanced, 2-period, 2-sequence, 2-way crossover design. Plasma concentrations of gemifloxacin were analyzed by a validated and sensitive HPLC assay developed in-house. The mean plasma concentration-time profiles are almost superimposable. 18 ANOVAs were performed to compare gemifloxacin plasma levels of the two formulations at each sampling time and there were no statistical differences between the two formulations. The parameters used to measure bioavailability were AUC0-t, AUC0-infinity and Cmax and they were calculated by a model-independent method. The parametric 90% confidence intervals of the mean values for the test/reference ratio were in each case well within the bioequivalence acceptable boundaries of 80-125% for AUCo-t, AUC0-infinity and Cmax. Data obtained in this study prove, by appropriate statistical methods, the essential similarity of plasma levels of gemifloxacin from the test product with those from the reference product suggesting equal clinical efficacy of these two products.

Generic ciprofloxacin tablets contain the stated amount of drug and different impurity profiles: A 19F, 1H and DOSY NMR analysis.

The objective of this study was to control the purity of 16 commercial formulations of ciprofloxacin tablets purchased in different countries or via the Internet using 19F and 1H nuclear magnetic resonance (NMR). Twelve out of the sixteen commercial formulations of ciprofloxacin measured by 19F NMR contain the active ingredient within 100+/-5% of stated concentration. Three formulations have a lower ciprofloxacin content between 90 and 95% and one shows a higher concentration superior to 105%. The impurity profile was characterised using 19F and 1H NMR, and is characteristic of the manufacturer. Four to twelve fluorinated impurities among them fluoride ion and two already known compounds were detected and quantified in the sixteen formulations analysed by 19F NMR. Two other non-fluorinated impurities were observed in the seven formulations analysed with 1H NMR. The total content of impurities as well as their individual levels are in agreement with those reported previously in the few studies devoted to ciprofloxacin purity. However, all the formulations do not comply with the limits for impurities given in the ciprofloxacin monograph of the European Pharmacopeia. Finally, a "signature" of the formulations was obtained with Diffusion-Ordered SpectroscopY (DOSY) 1H NMR which allowed the characterisation of some excipients present in the formulations studied.

HPLC determination of ciprofloxacin, cloxacillin, and ibuprofen drugs in human urine samples.

This paper reports, for the first time, a liquid chromatographic method for the simultaneous determination of three frequently co-administered active principles, two antibiotics, ciprofloxacin (CIPRO) and cloxacillin (CLOXA) belonging to the fluoroquinolones and beta-lactam families, respectively, and ibuprofen (IBU), a non-steroidal anti-inflammatory drug. The chromatographic separation was performed on a C-18 analytical column, using isocratic elution with methanol-acetonitrile-pH 3 formate buffer (CT = 0.1 M) (15:12:73, v/v/v) for 3 min and, after that, a linear gradient with methanol-acetonitrile (88:12, v/v) for 8 min. Several absorption spectra were obtained for each peak using a DAD detector. Chromatograms at the maximum absorption wavelength for each analyte, 220 nm for both IBU and CLOXA, and 280 nm for CIPRO were selected as the most suitable. The proposed chromatographic method requires about 15 min per sample. The presence of a urine background was tested and no interference was found. The method was satisfactorily applied to the determination of CIPRO, CLOXA, and IBU, in fortified urine, and in urine samples from a patient undergoing treatment with these three active principles, among others. Limits of quantification in urine were 1.00, 1.70, and 2.87 microg/mL for CIPRO, CLOXA, and IBU, respectively.

Variability in the content of Indian generic ciprofloxacin eye drops.

BACKGROUND/AIMS: Under-potent generic antibiotics sold in developing world countries may be contributing to positive selection of resistance organisms and to unpredictability in clinical outcome, leading to a loss of confidence among physicians locally. The objective of this study was to determine whether reports of unpredictable outcome for generic ciprofloxacin antibiotic eye drops in India could be the result of inadequate concentration of preparations sold by pharmacies. METHODS: 130 ciprofloxacin eye drop samples sold by pharmacies were collected from seven locations in north, central, and south India; 30 were randomly selected for testing. All samples were assayed using validated methods of reverse phase chromatography and fluorescence detection at a international antibiotic reference laboratory in the United Kingdom. Results were compared with advertised concentrations within the context of internationally accepted variability ranges. RESULTS: In total, six out of the 30 samples tested had ciprofloxacin concentrations lower than the standard advisory ranges of plus or minus 5% of stated content for 3 mg/ml pharmaceutical preparations. The ciprofloxacin content of these eye drops ranged from -36.4% to -16.1% of the stated content (median -21.73%). 24 out of 30 samples were found to be over the standard advisory ranges of plus or minus 5%, at a median of +19.42% (interquartile range (IQR) +14.28 to +25.13). Intra-batch variability of two selected samples was wide at -22.83% to +33.93% (n=11) and -17.07% to +31.20% (n=12). CONCLUSIONS: Approximately 20% of generic ciprofloxacin eye drops, purchased without prescription in India were under-potent. In a number of preparations the antibiotic content was sufficiently low as to have a potential impact on clinical outcome and possibly lead to the selection of resistant isolates in individual patients. More widespread studies are justified to identify the extent of under-potency of widely used generic antibiotic medications in developing countries.

Determination of residues of enrofloxacin and its metabolite ciprofloxacin in chicken muscle by capillary electrophoresis using laser-induced fluorescence detection.

A method for the residue analysis of the veterinary antimicrobial agent enrofloxacin and its active desethyl metabolite ciprofloxacin in chicken muscle tissue has been developed and validated. The detection of the analytes was performed by laser-induced fluorescence (LIF) detection using a HeCd laser (lambda(ex) = 325 nm) providing an enhancement in sensitivity and selectivity compared to conventional UV detection. The assay has been validated with satisfying results. The limits of quantification for enrofloxacin and ciprofloxacin were 5 microg/kg and 20 microg/kg, respectively, with a fivefold preconcentration yielded by a sample clean-up with a simple liquid-liquid extraction procedure. Calibration graphs were linear from 5 to 1000 microg/kg for enrofloxacin and from 20 to 1000 microg/kg for ciprofloxacin. The assay allows the detection of contaminated muscle samples at the required maximum residue limit of the European Union, which is 100 microg/kg for the sum of enrofloxacin and ciprofloxacin.

Simple high-performance liquid chromatographic assay for the determination of ciprofloxacin in human plasma with ultraviolet detection.

A simple high-performance liquid chromatographic method is described for the quantitative analysis of ciprofloxacin in human plasma. Following protein precipitation from plasma by means of 6% perchloric acid, the upper layer which contains the analyte and the internal standard lomefloxacin, was analysed on a reverse phase column LiChrospher 60 RP-select B (5 microm) (EcoCART 125-3) with ultraviolet detection at 280 nm. The mobile phase was acetic acid 5%-methanol-acetonitrile (90:5:5, v/v/v). The assay was linear for ciprofloxacin over the concentration range of 0.050 to 6.00 microg ml(-1). The limit of quantification (LOQ) was 0.050 microg ml(-1). The method was successfully applied to a bioavailability study with five different ciprofloxacin formulations.

Efficacy of difloxacin in calves experimentally infected with Mannheimia haemolytica.

OBJECTIVE: To determine the efficacy of difloxacin, a novel fluoroquinolone antibiotic, in calves experimentally infected with Mannheimia haemolytica (formerly Pasteurella haemolytica). ANIMALS: Seventy-two 3-month-old Holstein calves. PROCEDURES: Calves were inoculated with M haemolytica intratracheally; after they developed clinical signs of pneumonic pasteurellosis, they were randomly assigned to 1 of 6 groups (n = 12/group). Calves in each group were treated with 10% difloxacin (2.5 or 5 mg/kg of body weight), 5% difloxacin (2.5 or 5 mg/kg), enrofloxacin (5 mg/kg), or saline (0.9% NaCl) solution (control group), once daily for 5 days, and clinical signs were scored daily. On day 15, calves were euthanatized, and the percentage of diseased lung tissue was calculated. Swab specimens of the lungs were submitted for bacterial culture. RESULTS: Mortality rate and percentage of diseased lung tissue were significantly higher and cure rate and average daily gain were significantly lower for control calves, compared with calves in the treatment groups; however, no significant differences were found among treatment groups. Mannheimia haemolytica was isolated from the lungs of 10 control calves and from at least 2 calves in each of the treatment groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that difloxacin and enrofloxacin were equally effective for treatment of calves with experimentally induced pneumonic pasteurellosis. However, treatment of infected calves with difloxacin or enrofloxacin may not eliminate the organism.

Compositional analysis surveillance of eleven brands of enrofloxacin including Baytril for veterinary use.

Lack of consistency in clinical effectiveness of various commercial preparations of enrofloxacin prompted a compositional analysis surveillance of 11 trade marks of this fluoroquinolone using various physicochemical properties and high performance liquid chromatography (HPLC). Only one preparation resembled Baytril (Bayer of Mexico), the original brand of enrofloxacin. Variations in the concentration of enrofloxacin, use of different vehicles, substitution of this fluoroquinolone by ciprofloxacin and variations in pH were found. The use of ciprofloxacin in veterinary medicine is discussed.