Cefuroxime axetil. A review of its antibacterial activity, pharmacokinetic properties and therapeutic efficacy

One-pot chemoenzymatic access to a cefuroxime precursor via C1 extension of furfural

In this work, one-pot three-step synthesis of (Z)-2-methoxyimino-2-(furan-2-yl)acetic acid (SMIA), a key precursor for cefuroxime, was reported from biomass-derived furfural in 81% yield via sequential whole-cell catalytic hydroxymethylation by Escherichia coli harboring pyruvate decarboxylase, chemoenzymatic oxidation by the laccase-TEMPO system, and spontaneous oximation. In gram-scale production, SMIA was obtained in 63% isolated yield.

Visible-light-induced copper-catalyzed oxidative esterification of α-azidoketones with diazoacetates: access to α-acyloxyacetates

A copper(II)-catalyzed 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-mediated synthesis of α-acyloxyacetates from α-azidoketones and diazoacetates under visible light at room temperature is described. This reaction involves an oxidative esterification process, leading to the formation of two new C-O bonds with the elimination of dinitrogen molecules in the overall process. 20 examples of α-acyloxyacetates were synthesized in high yields (70-86%) by coupling various α-azidoketones with diazoacetates. α-Azidoketones containing electron-donating groups (Me, MeO), electron-withdrawing groups (CN, NO2), halogen atoms (Cl, Br), and other aryl groups are compatible with various substituted diazoacetates (ethyl, tertiary butyl, benzyl), resulting in the formation of α-acyloxyacetates.

Sensitizing methicillin-resistant Staphylococcus aureus (MRSA) to cefuroxime: the synergic effect of bicarbonate and the wall teichoic acid inhibitor ticlopidine

Methicillin-resistant Staphylococcus aureus (MRSA) strains are a major challenge for clinicians due, in part, to their resistance to most β-lactams, the first-line treatment for methicillin-susceptible S. aureus. A phenotype termed "NaHCO3-responsiveness" has been identified, wherein many clinical MRSA isolates are rendered susceptible to standard-of-care β-lactams in the presence of physiologically relevant concentrations of NaHCO3, in vitro and ex vivo; moreover, such "NaHCO3-responsive" isolates can be effectively cleared by β-lactams from target tissues in experimental infective endocarditis (IE). One mechanistic impact of NaHCO3 exposure on NaHCO3-responsive MRSA is to repress WTA synthesis. This NaHCO3 effect mimics the phenotype of tarO-deficient MRSA, including sensitization to the PBP2-targeting β-lactam, cefuroxime (CFX). Herein, we further investigated the impacts of NaHCO3 exposure on CFX susceptibility in the presence and absence of a WTA synthesis inhibitor, ticlopidine (TCP), in a collection of clinical MRSA isolates from skin and soft tissue infections (SSTI) and bloodstream infections (BSI). NaHCO3 and/or TCP enhanced susceptibility to CFX in vitro, by both minimum inhibitor concentration (MIC) and time-kill assays, as well as in an ex vivo simulated endocarditis vegetations (SEV) model, in NaHCO3-responsive MRSA. Furthermore, in experimental IE (presumably in the presence of endogenous NaHCO3), pre-exposure to TCP prior to infection sensitized the NaHCO3-responsive MRSA strain (but not the non-responsive strain) to enhanced clearances by CFX in target tissues. These data support the notion that NaHCO3 is acting similarly to WTA synthesis inhibitors, and that such inhibitors have potential translational applications in the treatment of certain MRSA strains in conjunction with specific β-lactam agents.

Straightforward access to α-carbonyloxy esters and β-keto thioethers from aryldiazoacetates

A metal- and additive-free approach has been described for synthesizing α-carbonyloxy esters and β-keto thioethers from readily available aryldiazoacetates with carboxylic acids and thiol derivatives, respectively. α-Carbonyloxy esters and β-keto thioether derivatives were synthesized in good to high yields from aryldiazoacetates, carboxylic acids, and thiol derivatives decorated with various functional groups. Finally, the potential of the new approach is demonstrated through its application in gram-scale reactions and the synthesis of a few bioactive molecules.

Pathway to Construct α-Acyloxy Esters by B(C6F5)3-Catalyzed O-H Insertion of Carboxylic Acids with Sulfoxonium Ylides

We report the first example of B(C6F5)3-catalyzed O-H insertion reaction of sulfoxonium ylides and carboxylic acids, achieving efficient construction of diester moieties under metal-free condition. This protocol is characterized by broad substrate tolerance, particularly for various phenylacetic acids, and good compatibility with water/air condition, which is superior to most other methods.

Repositioning of Cefuroxime as novel selective inhibitor of the thyroid hormone activating enzyme type 2 deiodinase

The iodothyronine deiodinases constitute a family of three selenoenzymes regulating the intracellular metabolism of Thyroid Hormones (THs, T4 and T3) and impacting on several physiological processes, including energy metabolism, development and cell differentiation. The type 1, 2 and 3 deiodinases (D1, D2, and D3), are sensitive, rate-limiting components within the TH axis, and rapidly control TH action in physiological conditions or disease. Notably, several human pathologies are characterized by deiodinases deregulation (e.g., inflammation, osteoporosis, metabolic syndrome, muscle wasting and cancer). Consequently, these enzymes are golden targets for the identification and development of pharmacological compounds endowed with modulatory activities. However, until now, the portfolio of inhibitors for deiodinases is limited and the few active compounds lack selectivity. Here, we describe the cephalosporin Cefuroxime as a novel D2 specific inhibitor. In both in vivo and in vitro settings, Cefuroxime acts as a selective inhibitor of D2 activity, without altering the enzymatic activity of D1 and D3. By inhibiting TH activation in target tissues, Cefuroxime alters the sensitivity of the hypothalamus-pituitary axis and interferes with the central regulation of THs levels, and is thus eligible as a potential new regulator of hyperthyroid pathologies, which affect thousands of patients worldwide.

Are We Hitting the Target?: The Effectiveness of Distinct Antibiotic Regimens in Pediatric Appendectomies

BACKGROUND

Currently, a range of different antibiotics are administered perioperatively during appendectomy surgery in the pediatric population. One reason for the lack of a uniform treatment regimen is the paucity of large studies on microbiologic data and susceptibility patterns.

METHODS

A retrospective, monocentric study on antibiotic susceptibility, including 1258 pediatric patients undergoing appendectomy from 2012 to 2020 was performed. Predictors for prolonged length of stay (LOS) and complications were determined using regression analysis, and objective criteria for broad-spectrum antibiotic regimens were identified. Simulations of the effectiveness of different antibiotic regimens against identified bacterial susceptibility results were conducted.

RESULTS

The most important predictors for prolonged LOS and an increased incidence of infectious complications are elevated preoperative C-reactive protein levels, high intraoperative severity gradings and insufficient primary antibiotic treatment. Based on our results, a simple antibiotic treatment, consisting of cefuroxime-metronidazole (C-M) or ampicillin-sulbactam (AS), is sufficient in around 85% of all patients; both options being equally efficient. In severe appendicitis, the likelihood of resistance is 31% and 32% for C-M and AS, respectively. For piperacillin-tazobactam and C-M-tobramycin, the incidence of bacterial resistance decreases to 12%. Resistance is reduced to 8% for AS-tobramycin treatment. The patient populations benefiting most from an extended antibiotic regimen are those with a high intraoperative severity grading.

CONCLUSIONS

Evidence suggests that an insufficient antibiotic regimen is associated with a prolonged LOS and a higher rate of infectious complications, justifying the expansion of a simple antibiotic regimen in cases of severe intraabdominal findings. In all other cases, a simple antibiotic treatment with AS is recommended.

Optimization of a Cefuroxime Axetil-Loaded Liquid Self-Nanoemulsifying Drug Delivery System: Enhanced Solubility, Dissolution and Caco-2 Cell Uptake

Cefuroxime axetil (CA) is an oral cephalosporin which hydrolyzes rapidly to the active parent compound cefuroxime. CA is known to have incomplete oral bioavailability (30−50%) due to its poor solubility and enzymatic conversion to cefuroxime in the gut lumen. In order to overcome these drawbacks, a lipid-based self-nanoemulsifying drug delivery system (SNEDDS) has been developed and optimized. The SNEDDS formulations were prepared using the aqueous phase titration method. The greatest self-emulsifying area was found in the 2:1 Smix ratio. As a result, different SNEDDS formulations were carefully selected from this phase diagram based on their smaller droplet size < 100 nm, polydispersity index ≤ 0.5, dispersibility (Grade A), and transmittance (%) > 85%. Thermodynamic stability tests were carried out in order to rule out any metastable/unstable SNEDDS formulations. The droplet size, polydispersity index, zeta potential, and entrapment efficiency (% EE) of optimized CA-loaded SNEDDS (C-3) were 18.50 ± 1.83 nm, 0.064 ± 0.008, −22.12 ± 1.20 mV, and 97.62 ± 1.06%, respectively. In vitro release studies revealed that the SNEDDS formulation had increased CA solubility. CA-SNEDDS-C3 increased CA cellular uptake, possibly due to increased CA solubility and the inhibition of enzymatic conversion to cefuroxime. Finally, in terms of the improvement of oral bioavailability, CA-loaded-SNEDDS could be a viable alternative to commercially available CA formulations.

Carboxylic Acid Functionalization Using Sulfoxonium Ylides as a Carbene Source

Functionalization of carboxylic acids using sulfoxonium ylides in the presence of [VO(acac)₂] as a catalyst is reported. The usual carbene source, diazo compounds, failed to produce α-carbonyloxy esters in good yield when compared to sulfoxonium ylides. Various standard spectroscopic and analytical techniques were used to characterize the products formed.

FDA-Approved Oximes and Their Significance in Medicinal Chemistry

Despite the scientific advancements, organophosphate (OP) poisoning continues to be a major threat to humans, accounting for nearly one million poisoning cases every year leading to at least 20,000 deaths worldwide. Oximes represent the most important class in medicinal chemistry, renowned for their widespread applications as OP antidotes, drugs and intermediates for the synthesis of several pharmacological derivatives. Common oxime based reactivators or nerve antidotes include pralidoxime, obidoxime, HI-6, trimedoxime and methoxime, among which pralidoxime is the only FDA-approved drug. Cephalosporins are β-lactam based antibiotics and serve as widely acclaimed tools in fighting bacterial infections. Oxime based cephalosporins have emerged as an important class of drugs with improved efficacy and a broad spectrum of anti-microbial activity against Gram-positive and Gram-negative pathogens. Among the several oxime based derivatives, cefuroxime, ceftizoxime, cefpodoxime and cefmenoxime are the FDA approved oxime-based antibiotics. Given the pharmacological significance of oximes, in the present paper, we put together all the FDA-approved oximes and discuss their mechanism of action, pharmacokinetics and synthesis.

Repurposing cefuroxime for treatment of COVID-19: a scoping review of in silico studies

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of Coronavirus disease 19 (COVID-19), is a novel human Coronavirus that is responsible for about 300,000 deaths worldwide. To date, there is no confirmed treatment or vaccine prevention strategy against COVID-19. Due to the urgent need for effective treatment, drug repurposing is regarded as the immediate option. Potential drugs can often be identified via in silico drug screening experiments. Consequently, there has been an explosion of in silico experiments to find drug candidates or investigate anecdotal claims. One drug with several anecdotal accounts of benefit is Cefuroxime. The aim of this study was to identify and summarize in silico evidence for possible activity of Cefuroxime against SARS-CoV-2.To this end, we performed a scoping review of literature of in silico drug repurposing experiments for SARS-CoV-2 using PRISMA-ScR. We searched Medline, Embase, Scopus, Web of Knowledge, and Google Scholar for original studies published between 1st Feb, 2020 and 15th May, 2020 that screened drug libraries, and identified Cefuroxime as a top-ranked potential inhibitor drug against SARS-CoV-2 proteins. Six studies were identified. These studies reported Cefuroxime as a potential inhibitor of 3 key SARS-CoV-2 proteins; main protease, RNA dependent RNA polymerase, and ACE2-Spike complex. We provided a summary of the methodology and findings of the identified studies. Our scoping review identified significant in silico evidence that Cefuroxime may be a potential multi-target inhibitor of SARS-CoV-2. Further in vitro and in vivo studies are required to evaluate the potential of Cefuroxime for COVID-19.Communicated by Ramaswamy H. Sarma.

Oral cephalosporin and β-lactamase inhibitor combinations for ESBL-producing Enterobacteriaceae urinary tract infections

ESBL-producing Enterobacteriaceae as uropathogens have given rise to a sizeable amount of global morbidity. Community and hospital surveillance studies continue to report increasing proportions of these organisms as causes of urinary tract infection (UTI). Due to limited treatment options and the presence of cross-resistance amongst oral antibiotics of different classes, patients often require IV therapy, thereby increasing healthcare costs and reducing the effectiveness of delivering healthcare. Oral cephalosporin antibiotics are well known for their ability to achieve high urinary concentrations, in addition to achieving clinical success for treatment of uncomplicated UTI with a drug-susceptible pathogen. Novel cephalosporin/β-lactamase inhibitor combinations have been developed and demonstrate good in vitro activity against ESBL-producing isolates. A pooled analysis of in vitro activity of existing oral cephalosporin/clavulanate combinations in ESBL-producing Enterobacteriaceae has shown MIC50s of 0.5-1, 0.125-1 and 0.25 mg/L for cefpodoxime, ceftibuten and cefixime, respectively. A novel cyclic boronic acid β-lactamase inhibitor, QPX7728, was able to produce MIC50 values of 0.5 and ≤0.06 mg/L when paired with cefpodoxime and ceftibuten, respectively. Other novel combinations, cefpodoxime/ETX0282 and ceftibuten/VNRX7145, have also demonstrated excellent activity against ESBL producers. Clinical trials are now awaited.

Prescribed drugs containing nitrogen heterocycles: an overview

Heteroatoms as well as heterocyclic scaffolds are frequently present as the common cores in a plethora of active pharmaceuticals natural products. Statistically, more than 85% of all biologically active compounds are heterocycles or comprise a heterocycle and most frequently, nitrogen heterocycles as a backbone in their complex structures. These facts disclose and emphasize the vital role of heterocycles in modern drug design and drug discovery. In this review, we try to present a comprehensive overview of top prescribed drugs containing nitrogen heterocycles, describing their pharmacological properties, medical applications and their selected synthetic pathways. It is worth mentioning that the reported examples are actually limited to current top selling drugs, being or containing N-heterocycles and their synthetic information has been extracted from both scientific journals and the wider patent literature.

Effect of food on the pharmacokinetics of oral cefuroxime axetil in dogs

Cefuroxime axetil pharmacokinetic profile was investigated in 12 Beagle dogs after single intravenous and oral administration of tablets or suspension at a dose of 20 mg/kg, under both fasting and fed conditions. A three-period, three-treatment crossover study (IV, PO under fasting and fed condition) was applied. Blood samples were withdrawn at predetermined times over a 12-hr period. Cefuroxime plasma concentrations were determined by HPLC. Data were analyzed by compartmental analysis. No statistically significant differences were observed between formulations and feeding conditions on PK parameters. Independently of the feeding condition, absorption of cefuroxime axetil after tablet administration was low and erratic. The drug has been quantified in plasma in 3 out of 6 and 5 out of 6 dogs in the fasted and fed groups. For this formulation, the bioavailability (F), peak plasma concentration (C_max ), and area under the concentration-time curve (AUC) of cefuroxime axetil were significantly enhanced (p < .05) by the concomitant ingestion of food (32.97 ± 13.47-14.08 ± 7.79%, 6.30 ± 2.62-2.74 ± 0.66 µg/ml, and 15.75 ± 3.98-7.82 ± 2.76 µg.hr/ml for F, C_max, and AUC in fed and fasted dogs, respectively), while for cefuroxime axetil suspension, feeding conditions affected only the rate of absorption, as reflected by the significantly shorter absorption half-life (T_½(a) ) and time to peak concentration (T_max ) (0.55 ± 0.27-1.15 ± 0.19 hr and 1.21 ± 0.22-1.70 ± 0.30 for T_½(a) and T_max in fed and fasted dogs, respectively). For cefuroxime axetil tablets, T > MIC (≤1 µg/ml) was <2 hr in fasted and ≈4 hr in fed animals, and for cefuroxime axetil suspension, T > MIC (≤1 µg/ml) was ≈5 hr and for T >MIC (≤4 µg/ml) was ≈2.5 hr for fasted and fed dogs, respectively. Cefuroxime axetil as a suspension formulation seems to be a better option than tablets. However, its short permanence in plasma could reduce its clinical usefulness in dogs.

Preparation and evaluation of cefuroxime axetil gastro-retentive floating drug delivery system via hot melt extrusion technology

Cefuroxime Axetil (CA) is a poorly soluble, broad spectrum antibiotic which undergoes enzymatic degradation in gastrointestinal tract. The objective of the present study was to develop lipid-based gastro-retentive floating drug delivery systems containing CA using hot-melt extrusion (HME) to improve absorption. Selected formulations of CA and lipids were extruded using a twin screw hot-melt extruder. Milled extrudates were characterized for dissolution, floating strength, and micromeritic properties. Solid-state characterization was performed using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and hot-stage microscopy. In vitro characterization demonstrated that the formulations exhibited a sustained drug release profile for 12 h. All formulations showed desired floating and flow properties. Solid-state characterization revealed no phase separation and no chemical interactions between the drug and excipients. Based on in vitro study results, an optimized formulation (F8) was further evaluated for in vivo performance. Oral bioavailability (C_max and AUC_0-24h) of F8 was significantly higher than that of pure CA. This study describes the use of lipid-based gastro-retentive floating drug delivery systems to achieve desired sustained release profile for more complete dissolution which could potentially reduce enzymatic degradation. This study also highlights the effectiveness of HME technology to improve dissolution and bioavailability.

Pharmacological properties of oral antibiotics for the treatment of uncomplicated urinary tract infections

The therapeutic management of uncomplicated bacterial urinary tract infections (UTIs) is based on short-term courses of oral antibiotics. The preferred drugs are nitrofurantoin trimethoprim-sulfamethoxazole, fosfomycin trometamol, fluoroquinolones and β-lactam agents. The choice of agent for treating uncomplicated UTIs should be based on the pharmacokinetic characteristics of the molecule so that clinical benefit is optimized and the risk of antibacterial resistance is minimized. This article discusses the general pharmacokinetic-pharmacodynamic (PK/PD) aspects of antimicrobial chemotherapy, the PK/PD characteristics of oral antimicrobial agents for the treatment of uncomplicated UTIs and the pharmacological and therapeutic strategies for limiting or preventing bacterial resistance.

Complicated Intra-Abdominal Infections: The Old Antimicrobials and the New Players

Complicated intra-abdominal infections (cIAIs) are an important cause of morbidity and mortality worldwide. They are diagnosed when the initial abdominal organ infection has spread into the peritoneal space. Successful treatment relies on adequate source control and appropriate empiric antimicrobial therapy. Inappropriate antimicrobial therapy may result in poor patient outcomes and increases in healthcare costs. Current guidelines recommend several single and combination antimicrobial regimens; however, empiric antimicrobial treatment has been complicated by the increasing rates of resistant organisms, especially the extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. Additionally, the overuse of carbapenems to combat these resistant pathogens has contributed to the rise of carbapenemase-producing microorganisms, especially Klebsiella pneumoniae. This increasing resistance has prompted the development of novel antimicrobials like ceftazidime-avibactam and ceftolozane-tazobactam, whose activity extends to ESBL-producing microorganisms. Furthermore, the optimal duration of antimicrobial therapy is still unknown, and further research is necessary to find a definitive answer. This review will focus on antimicrobial therapies recommended by the current guidelines, the individual properties of these agents, appropriate duration of therapy, recent clinical trials, and place in therapy of the antimicrobial agents recently approved for the treatment of cIAIs.

No development of ciprofloxacin resistance in the Haemophilus species associated with pneumonia over a 10-year study

Background

The widespread overuse of antibiotics promotes the development of antibiotic resistance in bacteria, which can cause severe illness and constitutes a major public health concern. Haemophilus species are a common cause of community- and nosocomial-acquired pneumonia. The antibiotic resistance of these Gram-negative bacteria can be prevented through the reduction of unnecessary antibiotic prescriptions, the correct use of antibiotics, and good hygiene and infection control. This article examines, retrospectively, antibiotic resistance in patients with community- and nosocomial-acquired pneumonia caused by Haemophilus species.

Methods

The demographic, clinical, and laboratory data of all patients with community- and nosocomial-acquired pneumonia caused by Haemophilus species were collected from the hospital charts at the HELIOS Clinic, Witten/Herdecke University, Wuppertal, Germany, within a study period from 2004 to 2014. Antimicrobial susceptibility testing was performed for the different antibiotics that have been consistently used in the treatment of patients with pneumonia caused by Haemophilus species.

Results

During the study period of January 1, 2004, to August 12, 2014, 82 patients were identified with community- and nosocomial-acquired pneumonia affected by Haemophilus species. These patients had a mean age of 63.8 ± 15.5 (60 [73.2 %, 95 % CI 63.6 %–82.8 %] males and 22 [26.8 %, 95 % CI 17.2 %–36.4 %] females). Haemophilus species had a high resistance rate to erythromycin (38.3 %), ampicillin (24.4 %), piperacillin (20.8 %), cefuroxime (8.5 %), ampicillin-sulbactam (7.3 %), piperacillin-sulbactam (4.3 %), piperacillin-tazobactam (2.5 %), cefotaxime (2.5 %), and levofloxacin (1.6 %). In contrast, they were not resistant to ciprofloxacin in patients with pneumonia (P = 0.016).

Conclusion

Haemophilus species were resistant to many of the typically used antibiotics. Resistance toward ciprofloxacin was not detected in patients with pneumonia caused by Haemophilus species.

Formulation design and evaluation of Cefuroxime axetil 125 mg immediate release tablets using different concentration of sodium lauryl sulphate as solubility enhancer

Cefuroxime axetil immediate release tablets were formulated by direct compression method with different percentages of sodium lauryl sulphate (SLS) such as 0.5, 1.0, 1.5 and also without SLS. Resulting batches of tablets were evaluated by both pharmacopeial and non-pharmacopeial methods to ascertain the physico-mechanical properties. Dissolution test were carried out in different medium like 0.07 M HCl, distilled water, 0.1M HCl of pH 1.2 and phosphate buffers at pH 4.5 and 6.8 to observe the drug release against the respective concentration of SLS used. Later, test formulations were compared by f1(dissimilarity) and f2(similarity) factors using a reference brand of cefuroxime axetil. Significant differences (p<0.05) in dissolution rate were recorded with the change in concentration of SLS in different media. Test formulation T3 containing 1% SLS was found to be best optimized formulation based on assay, disintegration, dissolution and similarity and dissimilarity factors.

Efficacy and Tolerability of Eight Antimicrobial Regimens in the Outpatient Treatment of Exacerbations of Chronic Obstructive Pulmonary Disease

BACKGROUND: Bacterial infections are considered as the most important cause of exacerbations in patients with chronic obstructive pulmonary disease.AIM: To compare the efficacy and tolerability of eight antibiotics empirically administered for outpatient treatment of exacerbations of COPD.METHODS: We performed an observational study including 343 COPD patients with probable bacterial exacerbation (Group A and Group B COPD patients) managed in an outpatient setting. Eight antibiotic regimens each used 10 days were evaluated: amoxicillin/clavulonic acid, doxycycline, cefuroxime, cefixime, clarithromycin, roxithromycin, ciprofloxacin, and moxifloxacin. All patients were followed up for 30 days, with an intermediate visits at 5, 7 and 10 days at which the duration of symptoms and the side-effects of the drug were evaluated.RESULTS: The clinical success rate varied from 69.8% with doxycycline to 80.9% with moxifloxacin. The mean time to relief of symptoms varied from 5.6 days with moxifloxacin to 6.3 days with amoxicillin/clavulonic acid. Significant increase of the post-treatment FEV1value was registered in all treatment groups. Relapse within the first 20 days was registered in the group receiving doxycycline, clarithromycin, and ciprofloxacin. The prevalence of the adverse events was low varying from 6.7% with cefuroxime to 11.3% with ciprofloxacin.CONCLUSION: Our findings suggest high clinical success rate and high safety of all studied regimens.

Prodrugs for masking bitter taste of antibacterial drugs--a computational approach

DFT calculations for the acid-catalyzed hydrolysis of several maleamic acid amide derivatives revealed that the reaction rate-limiting step is determined on the nature of the amine leaving group. Further, it was established that when the amine leaving group was a secondary amine, acyclovir or cefuroxime moiety the tetrahedral intermediate formation was the rate-limiting step such as in the cases of acyclovir ProD 1- ProD 4 and cefuroxime ProD 1- ProD 4. In addition, the linear correlation between the calculated and experimental rates provided a credible basis for designing prodrugs for masking bitter taste of the corresponding parental drugs which have the potential to release the parent drug in a sustained release fashion. For example, based on the DFT calculated rates the predicted t₁/₂ (a time needed for 50 % of the reactant to be hydrolyzed to products) for cefuroxime prodrugs, cefuroxime ProD 1- ProD 4, were 12 min, 18 min, 200 min and 123 min, respectively.

Increasing oral absorption of polar neuraminidase inhibitors: a prodrug transporter approach applied to oseltamivir analogue

Poor oral absorption is one of the limiting factors in utilizing the full potential of polar antiviral agents. The neuraminidase target site requires a polar chemical structure for high affinity binding, thus limiting oral efficacy of many high affinity ligands. The aim of this study was to overcome this poor oral absorption barrier, utilizing prodrug to target the apical brush border peptide transporter 1 (PEPT1). Guanidine oseltamivir carboxylate (GOCarb) is a highly active polar antiviral agent with insufficient oral bioavailability (4%) to be an effective therapeutic agent. In this report we utilize a carrier-mediated targeted prodrug approach to improve the oral absorption of GOCarb. Acyloxy(alkyl) ester based amino acid linked prodrugs were synthesized and evaluated as potential substrates of mucosal transporters, e.g., PEPT1. Prodrugs were also evaluated for their chemical and enzymatic stability. PEPT1 transport studies included [(3)H]Gly-Sar uptake inhibition in Caco-2 cells and cellular uptake experiments using HeLa cells overexpressing PEPT1. The intestinal membrane permeabilities of the selected prodrugs and the parent drug were then evaluated for epithelial cell transport across Caco-2 monolayers, and in the in situ rat intestinal jejunal perfusion model. Prodrugs exhibited a pH dependent stability with higher stability at acidic pHs. Significant inhibition of uptake (IC(50) <1 mM) was observed for l-valyl and l-isoleucyl amino acid prodrugs in competition experiments with [(3)H]Gly-Sar, indicating a 3-6 times higher affinity for PEPT1 compared to valacyclovir, a well-known PEPT1 substrate and >30-fold increase in affinity compared to GOCarb. The l-valyl prodrug exhibited significant enhancement of uptake in PEPT1/HeLa cells and compared favorably with the well-absorbed valacyclovir. Transepithelial permeability across Caco-2 monolayers showed that these amino acid prodrugs have a 2-5-fold increase in permeability as compared to the parent drug and showed that the l-valyl prodrug (P(app) = 1.7 × 10(-6) cm/s) has the potential to be rapidly transported across the epithelial cell apical membrane. Significantly, only the parent drug (GOCarb) appeared in the basolateral compartment, indicating complete activation (hydrolysis) during transport. Intestinal rat jejunal permeability studies showed that l-valyl and l-isoleucyl prodrugs are highly permeable compared to the orally well absorbed metoprolol, while the parent drug had essentially zero permeability in the jejunum, consistent with its known poor low absorption. Prodrugs were rapidly converted to parent in cell homogenates, suggesting their ability to be activated endogenously in the epithelial cell, consistent with the transport studies. Additionally, l-valyl prodrug was found to be a substrate for valacyclovirase (K(m) = 2.37 mM), suggesting a potential cell activation mechanism. Finally we determined the oral bioavailability of our most promising candidate, GOC-l-Val, in mice to be 23% under fed conditions and 48% under fasted conditions. In conclusion, GOC-l-Val prodrug was found to be a very promising antiviral agent for oral delivery. These findings indicate that the carrier-mediated prodrug approach is an excellent strategy for improving oral absorption of polar neuraminidase inhibitors. These promising results demonstrate that the oral peptide transporter-mediated prodrug strategy has enormous promise for improving the oral mucosal cell membrane permeability of polar, poorly absorbed antiviral agents and treating influenza via the oral route of administration.

Development and in vivo evaluation of gastroretentive delivery systems for cefuroxime axetil

The purpose of this investigation was to design and develop gastroretentive dosage form for cefuroxime axetil using floating tablet approach with various grades of hydroxypropyl methyl cellulose. Cefuroxime axetil is known to have low bioavailability, short half-life and is absorbed largely from upper GIT. Sodium bicarbonate was used in the dosage form as a source of carbon-di-oxide to maintain buoyancy. In vitro dissolution study results indicated non-Fickian diffusion controlled drug release mechanism and was best fitted into Korsmeyer-Peppas equation. In vivo radiographic studies conducted in five healthy human volunteers for optimized formulation indicated over 6 h retention of tablet in the stomach region. Reproducible physical parameters indicated that the current formulation could be easily scaled-up.

Antimicrobials in urogenital infections

Urinary tract infections (UTIs) and male genital infections are amongst the most prevalent infections. A prudent antibiotic policy therefore has a large impact on society. The clinical classification in uncomplicated cystitis, uncomplicated pyelonephritis, complicated UTI and genital infections is useful, also for the right choice of antibiotic treatment. In this regard pharmacokinetic and pharmacodynamic aspects have to be considered. Nowadays in uncomplicated cystitis antibiotics exclusively reserved for this indication are preferred, such as fosfomycin trometamol, nitrofurantoin and pivmecillinam, in order to reduce antibiotic pressure in this extremely frequent entity. In complicated UTI a broad bacterial spectrum has to be considered. Different antibiotic substances should be used for treatment, such as penicillins, with β-lactamase inhibitors, cephalosporins or carbapenems, fluoroquinolones, aminoglycosides or cotrimoxazole, if tested susceptible. For genital infections the pharmacokinetic properties of the antibiotics should especially be considered, such as in prostatitis, where mainly fluoroquinolones and macrolides show sufficient pharmacokinetic parameters for treatment of bacterial infections. Furthermore in genital infections fastidious organisms, such as Chlamydia or Mycoplasma spp. have to be considered with respect to their antimicrobial susceptibility.

Prodrugs available on the Brazilian pharmaceutical market and their corresponding bioactivation pathways

The aim of this paper was to emphasize the importance of prodrug design to therapy, by examining examples available on the Brazilian pharmaceutical market. The principles of prodrug design are briefly discussed herein. Examples of prodrugs from many important therapeutic classes are shown and their advantages relative to the drugs they are derived from are also discussed. Considering the importance of these therapeutic classes, from both therapy and economic standpoints, prodrug design is a very valuable aspect in the research of new drugs and for the pharmaceutical industry as a whole.

New semiphysiological absorption model to assess the pharmacodynamic profile of cefuroxime axetil using nonparametric and parametric population pharmacokinetics

Cefuroxime axetil is widely used to treat respiratory tract infections. We are not aware of a population pharmacokinetic (PK) model for cefuroxime axetil. Our objectives were to develop a semiphysiological population PK model and evaluate the pharmacodynamic profile for cefuroxime axetil. Twenty-four healthy volunteers received 250 mg oral cefuroxime as a suspension after a standardized breakfast. Liquid chromatography-tandem mass spectrometry was used for drug analysis, NONMEM and S-ADAPT (results reported) were used for parametric population PK modeling, and NPAG was used for nonparametric population PK modeling. Monte Carlo simulations were used to predict the duration for which the non-protein-bound-plasma concentration was above the MIC (fT(>MIC)). A model with one disposition compartment, a saturable and time-dependent drug release from the stomach, and fast drug absorption from the intestine yielded precise (r > 0.992) and unbiased curve fits and an excellent predictive performance. The apparent clearance was 21.7 liters/h (19.8% coefficient of variation [CV]) and the volume of distribution 38.7 liters (18.3% CV). Robust (>or=90%) probabilities of target attainment (PTAs) were achieved by 250 mg cefuroxime given every 12 h (q12h) or q8h for MICs of <or=0.375 mg/liter or <or=0.5 mg/liter, respectively, for the bacteriostasis target fT(>MIC) of >or=40% and for MICs of <or=0.094 mg/liter or <or=0.375 mg/liter, respectively, for the near-maximal-killing target fT(>MIC) of >or=65%. For the >or=40% fT(>MIC) target, the PTAs for 250 mg cefuroxime q12h were >or=97.8% for Streptococcus pyogenes and penicillin-susceptible Streptococcus pneumoniae. Cefuroxime at 250 mg q12h or q8h achieved PTAs below 73% or 92%, respectively, for Haemophilus influenzae, Moraxella catarrhalis, and penicillin-intermediate S. pneumoniae for susceptibility data from various countries. Depending on the MIC distribution, 250 mg oral cefuroxime q8h instead of q12h should be considered, especially for more-severe infections that require near-maximal killing by cefuroxime.

Adverse events associated with the use of oral cephalosporins/cephems

Historically, oral cephalosporins represent one of the most widely used and safest classes of antimicrobials available. Typical adverse events have included nausea, vomiting, diarrhea, and hypersensitivity reactions. Other more serious events such as pseudomembranous colitis, although infrequent, may occur. The exact type and incidence of adverse events varies depending on the cephalosporin being administered. Differences in adverse event profiles may also vary by age of the patient. Reactions are usually not severe and often do not require termination of therapy. The purpose of this review is to present to healthcare providers the historical safety profile of the most commonly used oral cephalosporins.

Pharmacokinetic and pharmacodynamic aspects of antimicrobial agents for the treatment of uncomplicated urinary tract infections

Uncomplicated urinary tract infections (UTI) are treated with beta-lactams, co-trimoxazole, quinolones and fosfomycin tromethamine. Due to increasing resistance of causative pathogens, antibiotics should be used by considering their pharmacodynamic and pharmacokinetic characteristics. beta-lactams have time-dependent activity and should not be used once-daily. Co-trimoxazole should be restricted due to increasing chemoresistance. Fluoroquinolones play a primary role in the treatment of serious and complicated infections. Fosfomycin tromethamine is active against most urinary tract pathogens. In vitro time-kill kinetics of fosfomycin against Escherichia coli and Proteus mirabilis showed primarily concentration-dependent activity, with a prolonged post-antibiotic effect (3.4 to 4.7h). Based on these results a single 3g dose of fosfomycin guarantees optimal efficacy against common uropathogens with an AUC(urine)/MIC ratio of 500.

Flupenthixol and cefotiam: effects on vitamin A metabolism in rats

We examined the alterations in vitamin A metabolism as a result of flupenthixol or cefotiam administration. The impact of these drugs on indices of vitamin A status was evaluated in Brown Norway and Long-Evans rats. Intramuscular drug administration for 28 d resulted in a decline in systemic retinol. Changes in circulating retinol with time for chronic dosing showed drug treatment (P<0.001) and time (P<0.03) to be significant factors, but rat strain (P=0.33) was not a significant factor. Flupenthixol was the most active retinol-lowering compound (P<0.005). At the end of the 28 d period, hepatic retinyl ester hydrolase activity was greater in drug-treated rats than in controls (P<0.05). With regard to effects on liver reserves: (1) flupenthixol treatment resulted in vitamin A depletion (P<0.05); (2) cefotiam treatment stimulated vitamin A accumulation; (3) distinctive patterns of retinol and its esters were seen in response to treatment. It is reasonable to assume that the drugs interfere with vitamin A in at least two ways: (1) lowering of plasma retinol, an early event in the interaction, may be caused by inhibition of hepatic holo-retinol-binding protein secretion or stimulation of clearance, or both; (2) when plasma retinol levels are persistently low, and as the hepatic deposits of the xenobiotics build up, there are changes in the vitamin A pool size and composition of the liver. Candidate enzymes are retinyl ester hydrolase and cytochrome P450. The relationship between these two events will be studied in further detail.

Oral telithromycin 800 mg once daily for 5 days versus cefuroxime axetil 500 mg twice daily for 10 days in adults with acute exacerbations of chronic bronchitis

The efficacy and safety of a 5-day regimen of 800 mg telithromycin once daily was compared with a standard 10-day regimen of 500 mg cefuroxime axetil twice daily in a multicentre, randomized, double-blind, parallel-group trial involving 376 patients with acute exacerbations of chronic bronchitis (AECB). In clinically evaluable patients (n = 282), post-therapy clinical cure rates were 86.4% with telithromycin and 83.1% with cefuroxime axetil. In bacteriologically evaluable patients (n = 53), eradication or presumed eradication of the pathogen was achieved in 76.0% and 78.6% of telithromycin and cefuroxime axetil patients, respectively. Adverse events were mostly mild; the most common were diarrhoea (12.8% versus 11.8%) and nausea (8.9% versus 3.2%) in telithromycin and cefuroxime axetil patients, respectively. The 5-day regimen of 800 mg telithromycin once daily was similar in efficacy and equally well tolerated as a 10-day regimen of 500 mg cefuroxime axetil twice daily in adults with AECB.

Cefuroxime vs a dicloxacillin/chloramphenicol combination for the treatment of parapneumonic pleural effusion and empyema in children

The aim of this study was to evaluate the efficacy of cefuroxime, compared with the combination of dicloxacillin/chloramphenicol, for the treatment of children with parapneumonic pleural effusion or empyema. Forty patients, aged 3 months to 5 years, with pleural effusion or empyema were randomized to receive cefuroxime (100 mg/kg/day) IV (n=20) or chloramphenicol (100 mg/kg/day) plus dicloxacillin (200 mg/kg/day) IV (n=20). Both groups were similar in age, days of illness, clinical and radiological findings, and etiology. Most patients (70%) had an empyema at presentation. There was no difference in clinical outcomes, including days to defervescence, duration of respiratory distress, duration of chest tube drainage, and days to discharge from hospital. The complication rates were similar in both groups. Pleural thickening occurred in four patients, bronchopleural fistula in two, and loculated empyema in one patient of each treatment group. Adverse effects attributed to cefuroxime were mild and infrequent. These results suggest that cefuroxime is an effective and well-tolerated alternative for the treatment of children with pleural effusion and empyema.

Ecological effects on the oro- and nasopharyngeal microflora in children after treatment of acute otitis media with cefuroxime axetil or amoxycillin-clavulanate as suspensions

OBJECTIVE

To evaluate if the extent of normal microflora disturbances differed between treatment with amoxycillin-clavulanate administered in an active form and cefuroxime axetil administered as an inactive prodrug.

METHODS

Twenty-eight children, 0.5-5 years old, diagnosed with acute otitis media (AOM), were treated with either amoxycillin-clavulanate (13.3 mg/kg 3 times daily) or cefuroxime axetil (15 mg/kg twice daily) for 7 days. Saliva samples and nasopharyngeal swabs were collected before, directly after and 2 weeks after treatment. The saliva samples were quantitatively and qualitatively analyzed and the nasopharyngeal swabs were qualitatively analyzed. All isolated strains were tested for beta-lactamase production.

RESULTS

Both treatment regimens gave rise to similar alterations of the normal oropharyngeal microflora. In both groups, the amount of Streptococcus salivarius was significantly reduced (P < 0.05). The most common causative pathogens of acute otitis were S. pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. On the day of enrollment, approximately half of the patients, in both groups, were infected with more than one pathogen. The rate of infection or colonization with more than one potential pathogen was low on day 7 but recurred 2 weeks after treatment to similar levels as on day 0. The total number of patients with reinfection, recolonization or recurrence of pathogens on day 21 was 11/12 in the amoxycillin-clavulanate group and 4/7 in the cefuroxime axetil group. The most common beta-lactamase producer was M. catarrhalis.

CONCLUSION

The local high concentration of antibiotics in the oropharynx immediately after intake of antibiotic suspensions seem to have little or no impact on the extent of disturbance of the microflora in this region. Children of this age group seem prone to either reinfection, recolonization or persistence of pathogens within 2 weeks after treatment. Furthermore, co-infection with more than one pathogen seems common in children with AOM and infection with beta-lactamase producing microorganisms occurs frequently.

Clinical use of cefuroxime in paediatric community-acquired pneumonia

Cefuroxime has been recommended as a component of treatment for community-acquired pneumonia (CAP) in guidelines produced by several groups, including the US and British Thoracic Societies. It is effective in vitro against the major bacterial pathogens in CAP but it needs to be given with an agent that is active against Mycoplasma, Chlamydia or Legionella spp. if the presence of any of these organisms is suspected. Cefuroxime penetrates respiratory tissue effectively after either parenteral or oral administration, and it has a pharmacodynamic profile which suggests that adequate cover can be achieved with oral therapy for respiratory pathogens susceptible to cefuroxime concentrations of 4 mg/L or less. This break-point is applicable to oral monotherapy and to sequential therapy regimens for the treatment of pneumonia. Cefuroxime can be used either orally or parenterally and it is approved in many countries for the treatment of adult pneumonia by either route. The oral form, cefuroxime axetil, has been used extensively in the treatment of children aged over 3 months but its use in paediatric pneumonia has not been reviewed. The present review summarises clinical experience in the treatment of bacterial pneumonia, of varying severity, in children. The data show that children with severe pneumonia, including those with pleural effusion or complications, can be treated with a full course of intravenous cefuroxime therapy, whereas hospitalised children whose pneumonia stabilises rapidly after initial intravenous therapy can change to oral cefuroxime axetil after 24 to 72 hours and may be able to return home. Oral cefuroxime axetil was appropriate for patients with milder pneumonia managed either in hospital or at home.

Assessment of infant development during an 18-month follow-up after treatment of infections in pregnant women with cefuroxime axetil

BACKGROUND

Choices of antibacterial for infections in pregnancy are limited because of potential risks to the fetus, particularly in the early months. However, infections may result in preterm labour or other problems and so treatment is needed. Increasingly, resistance is reported among common pathogens to older agents, such as ampicillin or amoxicillin, that have been widely used in pregnancy.

OBJECTIVE

To assess the safety and efficacy of cefuroxime axetil in the treatment of infections during pregnancy.

DESIGN

This was a retrospective analysis of case records for women who were treated with cefuroxime axetil at some point during pregnancy.

SETTING

Patients were treated at one centre in Lubliniec, Poland in 1996 and 1997.

PATIENTS AND PARTICIPANTS

The study included 78 women aged 19 to 38 years (mean 26 years) and their 80 infants.

MAIN OUTCOME MEASURES AND RESULTS

Efficacy in treating maternal infections was assessed, and the physical and mental development of children born to treated mothers was evaluated for at least 18 months after birth. 13 women were treated in the first trimester, 19 in the second trimester and 46 in the third trimester. There were no abnormalities causing concern in terms of physical or mental development in any of the children, and no abnormality that was attributable to the treatment the mother had received.

CONCLUSIONS

The results add clinical support for the use of cefuroxime axetil in pregnancy if an antibacterial is needed, thus offering an alternative if antibacterial resistance to older agents is an issue for the pregnant mother.

Clinical and microbiological efficacy of single dose cefuroxime prophylaxis for dental surgical procedures

In a prospective controlled randomised trial of 59 patients the effect of a single dose of cefuroxime before multiple tooth extractions on the clinical findings and occurrence of bacteraemia was studied. In one group 1.5 g cefuroxime was administered intravenously 10 min before start of surgery. A total of 118 blood samples were collected after 10 and 40 min. The cefuroxime group had a significantly lower rate of bacteraemia (33%) compared with the control group (86%). The predominant bacteria were gram-positive cocci. Fifty four different strains of bacteria were isolated, of which most were susceptible to cefuroxime. However seven strains which were susceptible to cefuroxime in vitro, were isolated from blood cultures of the treated group. Serum concentrations of cefuroxime ranged from 52.3 to 141.6 mg/l at 10 min and 32.6 to 91.8 mg/l at 40 min with a mean of 78.6 and 55.1 mg/l respectively. The only other factor which had a significant influence on the rate of bacteraemia was the number of extracted teeth. Oral hygiene and periodontal status did not significantly affect bacteraemia. There were no wound infections in any of the groups. During these dental interventions, sufficient plasma levels of antibiotic prevented bacteraemia. Selected patients might benefit from single-dose-prophylaxis with cefuroxime in preparation for dental surgery.

Stereoselective absorption and hydrolysis of cefuroxime axetil diastereomers using the Caco-2 cell monolayer model

Cefuroxime axetil, the orally active prodrug of cefuroxime is marketed as a 1:1 mixture of two diastereomers designated as R (1'R, 6R, 7R) and S (1'S, 6R, 7R). Prodrug hydrolysis is thought to occur during intestinal absorption, however little is known concerning the relative availability of cefuroxime from each isomeric form. The Caco-2 cell monolayer model was used to examine the possible stereoselectivity of absorption by measuring the accumulation and epithelial transport rate in the apical to basolateral direction of cefuroxime and cefuroxime axetil following application of the mixture (1.0 mM) or individual diastereomers (0.5 mM0 of cefuroxime axetil. Cefuroxime appearance in the basolateral chamber was in the order: mixture > R > S following application of the prodrug. The accumulation of unchanged cefuroxime axetil was S > R irrespective of the form applied, i.e. individual diastereomer or the mixture. Such stereoselective differences in both absorption and/or hydrolysis may contribute to the observed oral bioavailability (30-50%) of cefuroxime in vivo.