Paper analytical devices for fast field screening of beta lactam antibiotics and antituberculosis pharmaceuticals.

Reports of low-quality pharmaceuticals have been on the rise in the past decade, with the greatest prevalence of substandard medicines in developing countries, where lapses in manufacturing quality control or breaches in the supply chain allow substandard medicines to reach the marketplace. Here, we describe inexpensive test cards for fast field screening of pharmaceutical dosage forms containing beta lactam antibiotics or combinations of the four first-line antituberculosis (TB) drugs. The devices detect the active pharmaceutical ingredients (APIs) ampicillin, amoxicillin, rifampicin, isoniazid, ethambutol, and pyrazinamide and also screen for substitute pharmaceuticals, such as acetaminophen and chloroquine that may be found in counterfeit pharmaceuticals. The tests can detect binders and fillers such as chalk, talc, and starch not revealed by traditional chromatographic methods. These paper devices contain 12 lanes, separated by hydrophobic barriers, with different reagents deposited in the lanes. The user rubs some of the solid pharmaceutical across the lanes and dips the edge of the paper into water. As water climbs up the lanes by capillary action, it triggers a library of different chemical tests and a timer to indicate when the tests are completed. The reactions in each lane generate colors to form a "color bar code" which can be analyzed visually by comparison with standard outcomes. Although quantification of the APIs is poor compared with conventional analytical methods, the sensitivity and selectivity for the analytes is high enough to pick out suspicious formulations containing no API or a substitute API as well as formulations containing APIs that have been "cut" with inactive ingredients.

Validation of the SL3 beta-Lactam Test for screening milk in compliance with U.S. pasteurized milk ordinance: performance tested method 040701.

The SL3 beta-Lactam Test is a 3 min, receptor-based lateral flow Rapid One Step Assay (ROSA) that detects 5 of 6 beta-lactam drugs approved for dairy cattle in the United States. The method was evaluated through the AOAC Research Institute Performance-Tested Method program following a U.S. Food and Drug Administration protocol. Three combined lots detected penicillin G 4.2 parts per billion (ppb), ampicillin 8.7 ppb, amoxicillin 7.8 ppb, cephapirin 16.0 ppb, and ceftiofur (total metabolites) 51 ppb at least 90% of the time, with 95% confidence as determined by dose response probit analysis. These detection levels are less than safe level/tolerances but not more than 50% less. Lot repeatability was within 20%. Incurred residues were detected comparably or more sensitively to fortified samples due to the cumulative effect of biologically active metabolites. There were no interferences from somatic cells at 1 M/mL, bacterial cells 500 000 colony-forming units/mL, or 30 other non-beta-lactam drugs. These performances met approval conditions of the National Conference on Interstate Milk Shipments. Ruggedness conditions were incorporated into public health procedures for annual laboratory proficiency and certification.

MRSA--the tip of the iceberg.

Methicillin-resistant Staphylococcus aureus (MRSA) strains cause serious nosocomial infections all over the world. Overall, approximately 20% of S. aureus isolates in Europe are reported as methicillin-resistant, whereas in US hospitals the prevalence ranges from 33% to 55%. The past few years have also witnessed an increase in life-threatening community-acquired infections caused by Panton-Valentine leukocidin-producing MRSA in the USA. Increasing use of glycopeptides for treatment of community-acquired MRSA infections may result in higher rates of glycopeptide resistance. Since 1996, five vancomycin-intermediate S. aureus (VISA; vancomycin MIC = 8-16 mg/L) strains have been identified in Europe, Asia and the USA, and vancomycin-resistant S. aureus (VRSA) strains (vancomycin MIC > or = 32 mg/L) have also been reported in the USA between 2002 and 2005. Most infections with VISA and VRSA have occurred in a setting of heavy prior use of glycopeptides and other antimicrobial agents. Emergence of reduced vancomycin susceptibility in S. aureus increases the possibility that currently available antimicrobial agents may become ineffective for treating systemic infections, especially bacteraemia, endocarditis and osteomyelitis. Ceftobiprole is a novel broad-spectrum cephalosporin with expanded activity against Gram-positive bacteria, including MRSA. Ceftobiprole is refractory to the development of endogenous resistance both in vitro and in vivo. The additional activity of ceftobiprole against MRSA strains makes it a potentially important addition to currently available agents.

Quantification of the carbapenem antibiotic ertapenem in human plasma by a validated liquid chromatography-mass spectrometry method.

BACKGROUND: Ertapenem (Invanz) is a newly developed carbapenem beta-lactam antibiotic. LC-MS is the method of choice for therapeutic drug monitoring (TDM) of a variety of drugs including antibiotics. No validated LC-MS method for ertapenem quantification is described in the literature so far. METHODS: A rapid and robust LC-MS quantification method for ertapenem was developed and validated for clinical routine application in plasma samples. After immediate stabilisation with MES buffer (pH 6.5), samples were prepared for LC-MS analysis using simple protein precipitation. LC-MS coupling was realised by the use of a Phenomenex Synergi 4micro Polar-RP A80 Mercury LC column (10 x 2.0 mm) in combination with a Single-MS (Agilent 1100 LC-MSD SL) operating in negative selected ion monitoring (SIM) detection mode with ceftazidime as internal standard for adequate selective and sensitive analysis. RESULTS: LC-MS method validation by means of determination of limit of detection (LOD 0.1 microg mL-1), lower limit of quantification (LLOQ 1 microg mL-1), linearity (0.1-50 microg mL-1), recovery (> 90%), intra- and inter-day precision (RSD < 10%), accuracy (> 90%), inter-subject variability (< 10% at LLOQ), drug stability in plasma (> 3 months) and in post-extracted samples (> 99% for 24 h), and matrix effects (process efficiency > 90%) showed excellent performance parameters considering Guidance for Industry - Bioanalytical Method Validation. CONCLUSION: This method is perfectly appropriate for routine quantification of ertapenem and possibly other polar carbapenem beta-lactam antibiotics.

Challenges in the analytical method development and validation for an unstable active pharmaceutical ingredient.

A sensitive high-performance liquid chromatography (HPLC) impurity profile method for the antibiotic ertapenem is developed and subsequently validated. The method utilizes an Inertsil phenyl column at ambient temperature, gradient elution with aqueous sodium phosphate buffer at pH 8, and acetonitrile as the mobile phase. The linearity, method precision, method ruggedness, limit of quantitation, and limit of detection of the impurity profile HPLC method are found to be satisfactory. The method is determined to be specific, as judged by resolving ertapenem from in-process impurities in crude samples and degradation products that arise from solid state thermal and light stress, acid, base, and oxidative stressed solutions. In addition, evidence is obtained by photodiode array detection studies that no degradate or impurity having a different UV spectrum coeluted with the major component in stressed or unstressed samples. The challenges during the development and validation of the method are discussed. The difficulties of analyzing an unstable active pharmaceutical ingredient (API) are addressed. Several major impurities/degradates of the API have very different UV response factors from the API. These impurities/degradates are synthesized or prepared by controlled degradation and the relative response factors are determined.

Faropenem medoxomil: a treatment option in acute bacterial rhinosinusitis.

Faropenem medoxomil is the first oral penem in a new class of beta-lactam antibiotics. Faropenem medoxomil has excellent in vitro activity against Streptococcus pneumoniae, Haemophilus influenzae and other key pathogens implicated in acute bacterial rhinosinusitis. Clinical studies have demonstrated that, in the treatment of acute bacterial rhinosinusitis in adults, 7 days of treatment with faropenem medoxomil is as clinically and bacteriologically effective as 10 days of treatment with cefuroxime axetil. One study showed faropenem medoxomil to be superior to cefuroxime axetil. Overall, the safety profile of faropenem medoxomil is similar to that of most comparators. Specifically, the minimal impact of faropenem medoxomil on the gastrointestinal flora leads to less diarrhea and other adverse events than coamoxicillin-clavulanate. Faropenem medoxomil has almost no drug-drug interactions and little requirement for dosage adjustments in the typical acute rhinosinusitis population.

La producción de betalactamasas y su inhibición / Lactamase production and its inhibition

La presencia de infecciones bucodentales constituye un hecho rutinario en la práctica odontológica, que en la mayor parte de los casos impone la realización de exodoncias, muchas veces por razones económicas. Este tratamiento se ve complementado con la utilización de agentes antimicrobianos. Después de la aparición de los antimicrobianos, hace más de 60 años, se advirtió sobre el uso y abuso equivocado con las consecuencias cada vez más problemáticas, por la aparición de bacterias resistentes que atenúan la eficacia de dichos agentes. Los seres vivos se resisten a morir y nadie tan determinado a seguir con vida como las bacterias. Es ampliamente conocido que el betalactámico de primera elección más utilizada en odontología es la amoxicilina, la cual hoy por problemas de automedicación e inframedicación, presenta gran resistencia bacteriana, la mayor parte de las cuales son causadas por las betalactamasas producidas por bacterias de la flora oral. El presente trabajo tiene como objetivo presentar el mecanismo de acción de los antibióticos betalactámicos y un breve estudio sobre la producción de betalactamasas, lo que contribuirá al conocimiento y utilización de los inhibidores de las mismas, tratando algunos aspectos referente a la microbiología oral, la resistencia bacteriana, las indicaciones y contraindicaciones, sus efectos benéficos y colaterales.