New cephalosporins

Spectrophotometric studies of low-cost method for determination of ceftriaxone using a novel charge transfer acceptor, N-(2,4-dinitro-1-naphthyl)-p-toluenesulphonamide

Background

This study reports a new, cost-effective and validated method for the determination of ceftriaxone (CFR). The method involved charge transfer (CT) complexation reaction of ceftriaxone (as n-electron donor) and N-(2,4-dinitro-1-naphthyl)-p-toluenesulphonamide {N-(2,4-DN1NL) PTS} as π-electron acceptor to form a complex. Ultraviolet, infrared and 1H NMR spectra of CFR, N-(2,4-DN1NL) PTS and adduct were then studied to predict the site of interaction between the donor and acceptor.

Result

The complex formed had deep golden-yellow colour, having a new absorption band at 440 nm. Molar absorptivity of 1.667 × 105 L M−1 cm−1 was obtained. The complexation reaction was completed at 30 °C optimal temperature within 10 min. Acetonitrile was found to be the best diluting solvent for optimal detector response and the complex was stable (absorbance unchanged) at room temperature for hours. At concentration of 1.708–11.956 µg mL−1, with low limits of detection of 0.143 µg mL−1, Beer’s law was observed. Between-day recovery statistics of CFR from quality control samples were 102.15 ± 0.062 (% RSD = 0.61, n = 12) over three days. The site of interaction of donor and acceptor molecules, as revealed through infrared (IR) and proton nuclear magnetic resonance studies (1H NMR) and the formation of charge transfer complex is through intermolecular hydrogen bonding between the amino group of the donor and the acidic proton of the acceptor. Common tablet excipients, as observed, did not interfere with the analytical method and no significant difference existed between the results of this new method and the high performance liquid chromatographic procedures (p > 0.05) documented in the USP. The new CT procedure described in this paper is not only simple but also fast, accurate and precise. Also, the reactions were carried out at room temperature compared to previously described procedures.

Conclusions

This novel method could therefore be adopted as a fast but cost-effective alternative for the qualitative and quantitative assessment of CFR in its pure and dosage form. It could find usefulness in on-the-spot detection of counterfeit drugs and in field inspections with reliable accurate results that compares with established methods.

The Chemical Relationship Among Beta-Lactam Antibiotics and Potential Impacts on Reactivity and Decomposition

Beta-lactam antibiotics remain one of the most commonly prescribed drug classes, but they are limited by their propensity to cause hypersensitivity reactions (e.g., from allergy to anaphylaxis) as well as by the emergence of bacteria with a myriad of resistance mechanisms such as β-lactamases. While development efforts continue to focus on overcoming resistance, there are ongoing concerns regarding cross-contamination of β-lactams during manufacturing and compounding of these drugs. Additionally, there is a need to reduce levels of drugs such as β-lactam antibiotics in waste-water to mitigate the risk of environmental exposure. To help address future development of effective remediation chemistries and processes, it is desired to better understand the structural relationship among the most common β-lactams. This study includes the creation of a class-wide structural ordering of the entire β-lactam series, including both United States Food and Drug Association (US-FDA)-approved drugs and experimental therapies. The result is a structural relational map: the “Lactamome,” which positions each substance according to architecture and chemical end-group. We utilized a novel method to compare the structural relationships of β-lactam antibiotics among the radial cladogram and describe the positioning with respect to efficacy, resistance to hydrolysis, reported hypersensitivity, and Woodward height. The resulting classification scheme may help with the development of broad-spectrum treatments that reduce the risk of occupational exposure and negative environmental impacts, assist practitioners with avoiding adverse patient reactions, and help direct future drug research.

Thinking Outside the Bug: Molecular Targets and Strategies to Overcome Antibiotic Resistance

Since their discovery in the early 20th century, antibiotics have been used as the primary weapon against bacterial infections. Due to their prophylactic effect, they are also used as part of the cocktail of drugs given to treat complex diseases such as cancer or during surgery, in order to prevent infection. This has resulted in a decrease of mortality from infectious diseases and an increase in life expectancy in the last 100 years. However, as a consequence of administering antibiotics broadly to the population and sometimes misusing them, antibiotic-resistant bacteria have appeared. The emergence of resistant strains is a global health threat to humanity. Highly-resistant bacteria like Staphylococcus aureus (methicillin-resistant) or Enterococcus faecium (vancomycin-resistant) have led to complications in intensive care units, increasing medical costs and putting patient lives at risk. The appearance of these resistant strains together with the difficulty in finding new antimicrobials has alarmed the scientific community. Most of the strategies currently employed to develop new antibiotics point towards novel approaches for drug design based on prodrugs or rational design of new molecules. However, targeting crucial bacterial processes by these means will keep creating evolutionary pressure towards drug resistance. In this review, we discuss antibiotic resistance and new options for antibiotic discovery, focusing in particular on new alternatives aiming to disarm the bacteria or empower the host to avoid disease onset.

Comparison of the effects of cefazolin and ceftriaxone on canine chondrocyte culture

Cephalosporins (CEFs) are antibiotics frequently used to treat bone infections and septic arthritis. The effects of CEFs on chondrocytes have not been studied until now. Cefazolin (cef1) and ceftriaxone (cef3), first-and third-generation CEFs, were selected to investigate their direct effects on normal and osteoarthritic (OA) primary canine chondrocytes, which were either nonstimulated or stimulated with the pro-inflammatory cytokine IL-1β. In our results, treatment with CEFs increased the negative effects on both conditioned normal and OA chondrocytes, especially when applied to IL-1β-stimulated cells (inflammatory stimulus). CEFs significantly decreased cell viability and induced apoptotic cell death in both normal and OA chondrocytes; moreover, treatment with cef1 caused necrotic cell death in OA chondrocytes. Cef3 treatment could increase s-GAG synthesis in normal cells preincubated with IL-1β, while cef1 had no significant effect. The expression of TNF was clearly downregulated after cef3 treatments, whereas it was upregulated after cef1 treatments. However, cef3 induced stronger downregulation of TIMP1 and the extracellular matrix component genes COL2A1 and ACAN. In conclusion, these results suggest both the cytotoxic effects of CEFs and their adverse effects on chondrogenic marker genes at the transcriptional level, which provide additional insight into the clinical application of cef1 and cef3.

Safety evaluation of cephalosporins based on utilization and adverse drug events: analysis of two databases in China

OBJECTIVE

The aim of this study is to evaluate the safety of cephalosporins, based on utilization and adverse drug events (ADEs).

METHODS

This is a retrospective study using data on cephalosporins, obtained from Yangtze River hospital drug information and the Wuhan adverse drug reactions monitoring center database, from January 2009 to December 2010, in 30 hospitals in China.

RESULTS

22/44 (55%) cephalosporins were third-generation, which accounted for more than 50% of total expenditure. The top five cephalosporins (sorted by their defined daily doses) were cefodizime sodium, cefoperazone/sulbactam sodium, cefaclor, cefixime and cefmenoxime hydrochloride, which were used 182.93, 110.63, 109.09, 101.47 and 100.05 defined daily dose per 10,000 days, respectively. Third-generation cephalosporins were responsible for 747/1337 ADEs (55.87%). In particular, 208 episodes (15.56%) were associated with ceftriaxone. The most frequently reported damages were involved in the skin and its appendages (967, 68.92%). 603 (45.10%) were identified as definite in causality evaluation. Cefaclor was found to be safer than other cephalosporins, whereas ceftriaxone was found to be less safe.

CONCLUSION

This retrospective evaluation demonstrated that overused and misused cephalosporins caused a relatively high incidence of ADEs. Therefore, surveillance should be strengthened successfully to optimize the rational use of cephalosporins.

Commonly used antibacterial and antifungal agents for hospitalised paediatric patients: implications for therapy with an emphasis on clinical pharmacokinetics

Due to normal growth and development, hospitalised paediatric patients with infection require unique consideration of immune function and drug disposition. Specifically, antibacterial and antifungal pharmacokinetics are influenced by volume of distribution, drug binding and elimination, which are a reflection of changing extracellular fluid volume, quantity and quality of plasma proteins, and renal and hepatic function. However, there is a paucity of data in paediatric patients addressing these issues and many empiric treatment practices are based on adult data. The penicillins and cephalosporins continue to be a mainstay of therapy because of their broad spectrum of activity, clinical efficacy and favourable tolerability profile. These antibacterials rapidly reach peak serum concentrations and readily diffuse into body tissues. Good penetration into the cerebrospinal fluid (CSF) has made the third-generation cephalosporins the agents of choice for the treatment of bacterial meningitis. These drugs are excreted primarily by the kidney. The carbapenems are broad-spectrum beta-lactam antibacterials which can potentially replace combination regimens. Vancomycin is a glycopeptide antibacterial with gram-positive activity useful for the treatment of resistant infections, or for those patients allergic to penicillins and cephalosporins. Volume of distribution is affected by age, gender, and bodyweight. It diffuses well across serous membranes and inflamed meninges. Vancomycin is excreted by the kidneys and is not removed by dialysis. The aminoglycosides continue to serve a useful role in the treatment of gram-negative, enterococcal and mycobacterial infections. Their volume of distribution approximates extracellular space. These drugs are also excreted renally and are removed by haemodialysis. Passage across the blood-brain barrier is poor, even in the face of meningeal inflammation. Low pH found in abscess conditions impairs function. Toxicity needs to be considered. Macrolide antibacterials are frequently used in the treatment of respiratory infections. Parenteral erythromycin can cause phlebitis, which limits its use. Parenteral azithromycin is better tolerated but paediatric pharmacokinetic data are lacking. Clindamycin is frequently used when anaerobic infections are suspected. Good oral absorption makes it a good choice for step-down therapy in intra-abdominal and skeletal infections. The use of quinolones in paediatrics has been restricted and most information available is in cystic fibrosis patients. High oral bioavailability is also important for step-down therapy. Amphotericin B has been the cornerstone of antifungal treatment in hospitalised patients. Its metabolism is poorly understood. The half-life increases with time and can be as long as 15 days after prolonged therapy. Oral absorption is poor. The azole antifungals are being used increasingly. Fluconazole is well tolerated, with high bioavailability and good penetration into the CSF. Itraconazole has greater activity against aspergillus, blastomycosis, histoplasmosis and sporotrichosis, although it's pharmacological and toxicity profiles are not as favourable.

Of bugs and drugs. A guide through the labyrinth of antimicrobial therapy for respiratory tract infections

Choosing appropriate antimicrobial therapy is no longer a simple process. Even for the common problems of respiratory tract disease in children and adults, selection is complicated by both increasing microbial resistance and the daunting number of extended-spectrum antibiotics now on the market. In this article, Drs Singh and Arrieta look at the problem from all aspects and give their specific recommendations.