Development and characterization of lyophilized cefpodoxime proxetil-Pluronic® F127/polyvinylpyrrolidone K30 solid dispersions with improved dissolution and enhanced antibacterial activity

The aim of this study was the development of hard-cellulose capsules containing cefpodoxime proxetil (CEF) (BCS Class II) loaded novel Pluronic® F127 (P127)/Polyvinylpyrrolidone K30 (PVP) solid dispersions (SDs) using ultrasonic probe induced solvent-lyophilization method for effective antibacterial treatment by means of improved saturated aqueous solubility, dissolution rate, reduced particle size, and wettability. SDs were evaluated for physical and solid-state analyses. The solubility of pure CEF was calculated as 0.269 ± 0.005 mg/mL, SDs formulated with P127/PVP exhibited increased solubility from 3.5- to 8-fold. Molecular distribution of CEF in SDs and formation of CEF loaded amorphous polymeric network were confirmed with morphological study, thermal analysis, Fourier-transform infrared spectroscopy (FT-IR), and 1H-NMR studies. Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), and Klebsiella pneumoniae (ATCC 700603) were used to investigate the antibacterial effectiveness of the SDs. The minimum inhibitory concentration (MIC) values of the P127/PVP SDs were found 2-8 times lower than the pure CEF. All SDs from hard-cellulose capsules exhibited significantly faster release than unprocessed CEF. The profiles of SDs and reference were detected to be dissimilar according to difference (f1) and similarity factor (f2). Hard-cellulose capsules containing CEF loaded P127/PVP SDs appear to be feasible alternative to commercially available CEF tablets for effective antibacterial therapy at lowest dose.

Taste-masking and colloidal-stable cubosomes loaded with Cefpodoxime proxetil for pediatric oral delivery

Drug administration failure has been often witnessed in pediatric due to children's resistance to take medicines with bitter taste. Taste-masking is the key requirement among the scanty drugs available for children. Solid taste-masking systems, such as tablets and capsules, are difficult to swallow for children. Therefore, a liquid taste-masking system based on lyotropic liquid crystalline nanoparticles (LLCNs) was developed in this study. Cefpodoxime proxetil (CFP), a typically bitter drug used as antibiotic in pediatric, was selected as the model drug, and the encapsulation of CFP into the LLCNs was envisaged to improve their taste. Pluronic F127 was added to improve the colloidal stability of CFP-LLCNs. The optimized CFP-LLCNs showed the particle size of 187.29 ± 4.12 nm and the encapsulation efficiency of 85.80%. The mesophase analysis by polarized light microscopy and small angle X-ray scattering confirmed the cubic phase of CFP-LLCNs. It showed a sustained-release profile well fitted to Higuchi model, indicating that diffusion and erosion were both responsible for the CFP release. The taste-masking ability of CFP-LLCNs was confirmed by electronic tongue, compared to CFP and commercial product. The colloidal stability was verified after 3 months storage in room condition (25 ± 2 °C, 70 ± 2%RH). To sum up, the taste-masking and colloidal-stable CFP-LLCNs showed great potential for pediatric oral delivery.

Evaluation of prophylactic antibiotic regimens on recurrence and mortality in spontaneous bacterial peritonitis

INTRODUCTION AND OBJECTIVES

Limited data describe current SBP epidemiology and specific secondary SBP prophylactic regimens, leading to variable prescribing practices. This work aims to compare 90-day and one-year SBP recurrence and mortality based on secondary SBP antibiotic prophylaxis regimens.

MATERIALS AND METHODS

We performed a retrospective cohort of patients >18 years with an SBP diagnosis from 2010 to 2015 at two academic institutions. Eligible patients had ascitic PMN counts ≥250cells/mm3 or a positive ascitic culture. Patients were compared based on secondary SBP prophylaxis regimens (i.e., daily, intermittent, or no prophylaxis).

RESULTS

Of 791 patients with ascitic fluid samples, 86 patients were included. Antibiotic prophylaxis included daily (n=34), intermittent (n=36), or no prophylaxis (n=16). Nearly half of SBP episodes had a positive ascitic fluid culture; 50% were gram-negative pathogens, and 50% were gram-positive pathogens. Daily and intermittent regimens had similar rates of recurrence at 90-days (19.4% vs. 14.7%, p=0.60) and one-year (33.3% vs. 26.5%, p=0.53). Similarly, mortality did not differ among daily and intermittent regimens at 90-days (32.4% vs. 30.6%, p=0.87) or one-year (67.6% vs. 63.9%, p=0.74). When comparing any prophylaxis vs. no prophylaxis, there were no differences in 90-day or one-year recurrence or mortality.

CONCLUSIONS

In patients with a history of SBP, our data indicate similar outcomes with daily, intermittent, or no secondary antibiotic prophylaxis. With available data, including ours, demonstrating a changing epidemiology for SBP pathogens, further data is required to determine if traditional approaches to secondary SBP prophylaxis remain appropriate.

Cefpodoxime proxetil as a therapeutic option in switching therapy for infective endocarditis in children: case reports and literature review

Infective endocarditis (IE) is uncommon in children, affecting predominantly subjects with congenital heart disease (CHD) and patients with indwelling central lines. The principles of antibiotic treatment in paediatric population are similar to those in adults. Prolonged intravenous administration of bactericidal rather than bacteriostatic agents is preferred. Outpatient intravenous therapy after initial treatment in the hospital may be considered only in selected patients. Partial oral treatment has been described in cases of left-sided, uncomplicated IE caused by common pathogens in adult patients. There are no guidelines or trials in paediatric population regarding switching therapy from intravenous to oral route. We present two cases of IE in children caused by uncommon pathogenic bacteria (Abiotrophia defectiva and Haemophilus parainfluenzae) successfully treated with oral third-generation cephalosporin - cefpodoxime proxetil after initial intravenous therapy. This paper provides observations on different therapeutic approach for IE in children as well as another potential use of cefpodoxime proxetil.

Levofloxacin versus Cefpodoxime for Antibacterial Prophylaxis in Allogeneic Stem Cell Transplantation

National guidelines recommend antimicrobial prophylaxis for allogeneic stem cell transplant patients during the pre-engraftment period because of increased infection risk during neutropenia. Fluoroquinolones have demonstrated lower rates of bacteremias and incidence of neutropenic fever, but there is limited evidence in the use of alternative antibacterials such as cefpodoxime. The primary objective of this study is to compare the rates of antibiotic prophylaxis failure between levofloxacin and cefpodoxime in allogeneic stem cell transplant recipients. Secondary objectives include comparing and characterizing number and type of infections, mortality at day 100 post-transplant, and hospitalizations for infectious causes in the first 100 days of transplant. This is a single-center, retrospective chart review of adult patients who received an allogeneic stem cell transplant from matched related and matched unrelated donors and antibacterial prophylaxis with levofloxacin or cefpodoxime from January 1, 2011, to October 1, 2014. A total of 142 patients were evaluated (71 levofloxacin, 71 cefpodoxime). Both levofloxacin and cefpodoxime groups had similar rates of neutropenic fever and antibiotic prophylaxis failure (58% versus 58%, P = NS). There were similar incidences of Clostridioides difficile and Multi-drug resistant (MDR) infections among both levofloxacin and cefpodoxime groups. Rates of infections, hospitalizations, and mortality in the first 100 days were similar among both groups. Cefpodoxime can be used as an alternative to levofloxacin for antibiotic prophylaxis in allogeneic stem cell transplant patients.

Disposition of ceftizoxime in Staphylococcal mastitis in Indian crossbred cows

Disposition of ceftizoxime was studied in Indian crossbred cows following a single IV dosing in field conditions. Six healthy lactating and six mastitic crossbred cows were assigned to two groups (Group 1 and Group 2). A single IV administration of ceftizoxime at the dose rate of 20mg/kg was administered to cows in both groups. Peak concentrations were recorded at 5min, decreasing sharply until 1h with plasma concentrations of 46.38±0.30μg/mL; concentrations were below detection limits at 24h. Ceftizoxime achieved peak concentrations at 96h and persisted up to 120h at a concentration of 36.71±0.96μg/mL in the milk of mastitic Indian crossbred cows. Staphylococcal colony count in acute mastitis was 52.33±4.98×10⁵ colony forming units/mL milk and no growth was detected at 96h post-dosing, indicating that ceftizoxime following single IV administration at 20mg/kg may be effective to treat acute staphylococcal mastitis.

Roultella ornithinolytica infection in infancy: a case of febrile urinary tract infection

Raoultella ornithinolytica is a Gram-negative, non-motile, encapsulated, aerobic bacillus belonging to the Enterobacteriaceae family. R. ornithinolytica is a not very common, but emergent causal agent of human infection, and its expression of beta-lactamase provides resistance to commonly used antibiotics. The pathogenetic potential of R. ornithinolytica isolates in human disease has become increasingly important. Several cases of hospital-acquired infection, mostly associated with invasive procedures, or in patients with co-morbidity caused by R. ornithinolytica, have been previously reported in the adult population. In pediatric population, two cases in immunocompromised children, one case in an infant with visceral heterotaxy and one case of catheter-related bacteraemia are described. Here, we present the first case of febrile urinary tract infection due to R. ornithinolytica in an 8-month-old infant, recovered from a previous febrile UTI caused by E. coli and without co-morbidity. The empiric therapy with ceftriaxone, followed by cefpodoxime proxetil, resolved symptoms: the clinical condition of the infant improved rapidly and the treatment eradicated urine from the R. ornithinolytica infection. Since other pathogens rather than R. ornithinolytica are usually identified in children with urinary tract infections, including Escherichia coli, Proteus, Klebsiella and Pseudomonas, the identification of this microorganism in our patient's urine was also unexpected.

Validated HPLC method for the pharmacokinetic study of oral extended-release cefpodoxime proxetil chitosan-alginate beads in rabbits

The aim of this study is to develop a simple and applicable HPLC method for the detection of cefpodoxime acid (CFA) in rabbit plasma after oral administration of cefpodoxime proxetil (CFP) loaded chitosan-alginate (CH-ALG) beads formulation. CFP is a prodrug that is deesterified in vivo to its active metabolite CFA to exhibit antibiotic activity. Chromatographic separation of CFA and internal standard (IS) was achieved by a RP18(C18), Phenomenax®100, (250×4.6mm) with the mobile phase consisting of (0.02mol/l (20mM) ammonium acetate solution and acetonitrile (92:8, v/v, pH=4.6) at a flow rate of 1.0ml/min. The method was validated according to the requirements of US-FDA guidelines for bioanalytical method validation. The linear regression analysis for the calibration plots showed good linear relationship (R2=0.9905) in the working concentration range of 0.5-50μg/ml. The limits of detection and quantification (S/N=3) were 0.069 and 0.136μg/ml. Plasma CFA levels were successfully determined in rabbit with satisfactory precision and accuracy. The analyte was found to be stable after a number of stability studies. The proposed HPLC method was successfully applied to pharmacokinetic study in rabbits for CFP loaded CH-ALG beads and marketed immediate release (IR) tablets. All pharmacokinetic parameters were assessed.

Endocarditis tricuspid sub-aigue of post abortion: report of a case

Tricuspid infective endocarditis is rare and represents five to 10% of all cases of infective endocarditis. It occurs predominantly in intravenous drug users, and patients with central venous catheters or intracardiac probes. We report on the case of subacute tricuspid infective endocarditis in a girl of 17 years. She had no particular cardiovascular history. She was admitted for a persistent fever with cachexy, cough and thoracic pains, and right heart failure that appeared one month after a clandestine abortion. Transthoracic echocardiography found several vegetations on the tricuspid valve with massive tricuspid regurgitation. The chest X-ray showed bilateral excavated lung abscesses and condensation areas. Blood culture was not done and broad-spectrum antibiotic therapy was given. She was apyretic after 10 days. However, the massive tricuspid regurgitation with right heart failure persisted. She was discharged from hospital after 40 days of treatment. Although rare, infective endocarditis is one of the more serious complications of gynaecological procedures, particularly clandestine abortion. Therefore any young girl with persistent fever must be suspected of clandestine abortion.

[Cutaneous infection with Aggregatibacter actinomycetemcomitans]

BACKGROUND

Aggregatibacter actinomycetemcomitans is a small, gram-negative, non-motile, coccobacillus. Aggregatibacter actinomycetemcomitans is known to cause periodontal disease and to be associated with actinomycosis.

CASE REPORT

We report a patient developed a chronic wound following trauma about the right heel. The lesion resolved after oral antibiotic therapy with cefpodoxime und surgical debridement. Bacterial cultures grew abundant Aggregatibacter actinomycetemcomitans, but no actinomyces species.

OBJECTIVE

The importance of Aggregatibacter actinomycetemcomitans in chronic wounds needs to be explored.

Pharmacokinetics and pharmacodynamics of oral and intravenous cefetamet in dog

The pharmacokinetic (PK) and pharmacodynamic (PD) properties of intravenously (IV) administered cefetamet-Na and per os (PO) administered cefetamet pivoxil were investigated in eighteen healthy dogs at three different dose levels. The three doses for IV cefetamet-Na were 95, 190 and 380 mg, while those for oral cefetamet pivoxil were 125, 250 and 500 mg (both equivalent to 90, 180 and 360 mg of cefetamet). An efficacy predictor, measured as the ratios of the time that the concentration of the free drug is over the MIC90 (T > MIC90) and the dosing interval (f% T > MIC90) of IV and PO administration were calculated. The PK parameters' maximum concentration (C max), half-life (t 1/2) and area under the curve (AUC0-t ) after three IV doses were 42.85 ± 11.79 μg/mL, 1.66 ± 0.36 h and 80.10 ± 28.92 mg h/L (95 mg); 93.50 ± 30.51 μg/mL, 1.47 ± 0.13 h and 1.47 ± 0.13 mg h/L (190 mg); 185.74 ± 113.83 μg/mL, 1.60 ± 0.38 h and 263.20 ± 73.27 mg h/L (380 mg). After PO administration, the C max, t 1/2 and AUC0-t at three doses were 9.25 ± 1.02 μg/mL, 1.79 ± 0.50 h and 31.90 ± 4.76 mg h/L (125 mg); 9.75 ± 1.77 μg/mL, 1.93 ± 0.65 h and 42.69 ± 8.93 mg h/L (250 mg); 15.55 ± 6.65 μg/mL, 2.02 ± 0.54 h, and 68.72 ± 24.11 mg h/L (500 mg). The IV f% T > MIC90 was greater than PO f% T > MIC90 when MIC90 was within the range of 0.25-256 mg/L.

[Phase I clinical trial on the safety of injectable cefetamet sodium with a single dose in healthy volunteers]

OBJECTIVE

To investigate the safety and maximum tolerable dosage of injectable cefetamet sodium Sixty healthy volunteers were enrolled in this study. with a single infusion in Chinese healthy volunteers.

METHODS

A double-blinded, randomized, placebo-controlled design was adopted. Eight dosages ranging from 100 mg to 5 000 mg were tested. The pharmacokinetics of the drug was analyzed using a Latin square three-cross self-controlled design, with 12 healthy volunteers receiving 500 mg, 1 000 mg and 2 000 mg of injectable cefetamet sodium in a randomized sequence. Blood and urine samples were collected and analyzed using high performance liquid chromatography with UV detection. The main pharmacokinetics parameters were calculated with DAS2.0 software.

RESULTS

59 healthy volunteers completed the tolerance tests. Clinical adverse reactions occurred in 22.73% of participants in the test group and 6.67% of participants in the placebo group; but the difference was not statistically significant. Common adverse events included infusion pain and dizziness. Rare adverse events such as palpitations, diarrhea and rash occurred in participants in the test group. All of the adverse reactions were mild. Abnormal laboratory test results occurred in 43.18% participants in the test group and 53.33% participants in the placebo group; again the difference was not statistically significant. Common abnormal laboratory test results included abnormal bowel flora, stool abnormalities, abnormal urine and elevated serum potassium. After a single infusion of 500 mg, 1 000 mg and 2 000 mg of injectable cefetamet sodium, peak concentration of the drug at 0.5 h reached (37.92 +/- 7.43), (74.90 +/- 10.67) and (148.54 +/- 31.63) mg/L, with areas under concentration-time curve of (72.08 +/- 14.98), (144.28 +/- 24.57) and (286.66 +/- 54.25) (mg x h)/L, respectively. Their elimination half-life was (2.03 +/- 0.38), (2.04 +/- 0.26), and (2.12 +/- 0.26) h, respectively. The disposition of cefetamet was presented as a two-compartment model with linear kinetics. The 24-hour urinary accumulation excretion was 76.6%-67.5%.

CONCLUSION

The maximum single tolerated dose of injectable cefetamet sodium is 5 000 mg. The pharmacokinetics is a two-compartment model with linear kinetics within a dose range 500-2 000 mg.

Impact of unlabeled French antibiotic guidelines on antibiotic prescriptions for acute respiratory tract infections in 7 Pediatric Emergency Departments, 2009-2012

From November 2009 to October 2012, implementation of guidelines, unlabeled by the French Agency of Health Products, changed the categories of antibiotics prescribed for acute respiratory tract infections in 7 pediatric emergency departments. During the study, 36,413 acute respiratory tract infections-related antibiotic prescriptions were prescribed. Amoxicillin prescriptions rose from 30.0% to 84.7%, while amoxicillin-clavulanate and cefpodoxime prescriptions decreased to 10.2% and 2.5%, respectively.

Natural gum as mucoadhesive controlled release carriers: evaluation of cefpodoxime proxetil by D-optimal design technique

The present study deals with the development of mucoadhesive controlled release tablets of Cefpodoxime Proxetil to increase the gastric residence time and thus prolong drug release, reduce dosing frequency and improve oral bioavailability. Tablets were prepared using sodium alginate and karaya gum, a natural polymer, with a synthetic polymer hydroxypropylmethylcellulose (K100LV) and Karaya gum with HPMC K100LV in various ratios to optimize the drug release profile using D-Optimal technique. Pre- and post-compression parameters of tablets prepared with various formulations (S1-S9, C1-C9) were evaluated. The FTIR and DSC studies revealed that no physiochemical interaction between excipients and drug. The formulation S7 showed prolonged drug release, and the mechanism of drug release from the optimized formulation was confirmed using the Korsmeyer-Peppas model to be non-Fickian release transport and n value was found 0.605 indicating both diffusion and erosion mechanism from these natural gums. The optimized formulation showed mucoadhesive strength >35 g. An in vivo study was performed on rabbits using an X-ray imaging technique. The radiological evidence suggests that the tablets adheres (more than 10 hours) to a rabbit's stomach. No significant changes were found in the physical appearance, drug content, mucoadhesive study and in vitro dissolution pattern after storage at 40 °C/75% relative humidity for 3 months.

Multicenter, double-blind, randomized clinical trial of parenterally administered Cefoselis versus Cefepime for the treatment of acute bacterial infections

AIM

This study aims to evaluate the clinical efficacy and safety of intravenous Cefoselis injection for the treatment of acute moderate and severe bacterial infections.

PATIENTS AND METHODS

A multicenter, double-blind, randomized clinical trial was carried out using Cefepime as control. Patients received 1.0 g of either Cefoselis or Cefepime for moderate infections or 2.0 g for severe infections at an interval of 12 hours for 7 to 14 days. A total of 276 patients (138 with Cefoselis, 138 with Cefepime) with respiratory or urinary tract infections were enrolled in the study. Up to 137 and 124 patients receiving Cefoselis and 132 and 125 patients receiving Cefepime were eligible for the ITT (intent to treat) and PP (per protocol) analyses, respectively.

RESULTS

At the end of the treatment, the cure rates and effective rates were 59.68% (74/124) and 93.55% (116/124) with Cefoselis, and 56.00% (74/124) and 90.40% (116/124) with Cefepime. The bacterial eradication rates of the two groups were 90.32% and 93.85%, respectively. No statistical differences were observed on the above-mentioned parameters between the two groups (all p > 0.05). Adverse events, mainly mild aminotransferase elevation and mild leukopenia, were observed in 11.59% (16/138) and 13.77% (19/138) of patients with Cefoselis and Cefepime, respectively (p > 0.05).

CONCLUSIONS

Cefoselis is an effective and safe choice against acute moderate and severe respiratory infections and UTI (urinary tract infection).

Hinged circular fixator construct for correction of congenital metatarsal deformity in a foal

A five-week-old American Quarter Horse colt was presented for evaluation of a left hindlimb deformity and lameness. Radiographs of the left hindlimb revealed a varus deformity with recurvatum originating in the mid-diaphysis of the third metatarsal bone. Surgical correction was undertaken by performing an osteotomy through the centre of rotation of angulation located within the mid-diaphysis of the third metatarsal bone, and a four-ring hinged circular external fixator construct was applied. Distraction of the osteotomy site was performed over an 11 day period. Notable complications included failure of a fixation pin, infection of the surgical site, and temporary laxity of the supporting tendons and ligaments of the contralateral metatarsophalangeal joint. The fixator was maintained until there was sufficient bone formation to allow frame removal, 152 days after the initial surgery. Use of a hinged circular construct allowed for partial correction of the deformity with resultant lengthening and resolution of the lameness in this colt.

Self-nanoemulsifying drug delivery system of cefpodoxime proxetil containing tocopherol polyethylene glycol succinate

CONTEXT

Lipid based drug delivery systems have gained prominence in last decade for drugs with dissolution rate limited oral bioavailability.

OBJECTIVE

To improve the solubility, permeability and oral bioavailability of cefpodoxime proxetil, β-lactam antibiotic. It is BCS Class IV drug having solubility 400 µg/mL and 50% oral bioavailability.

MATERIALS AND METHODS

Self-nanoemulsifying drug delivery system (SNEDDS) using various surfactant and cosurfactants such as tween 80, tocopheryl polyethylene glycol succinate (TPGS), propylene glycol and Capmul MCM as oil phase were prepared. Ternary phase diagrams were constructed to identify stable microemulsion region. Percent transmittance studies helped to shortlist the surfactant-cosurfactant combination.

RESULTS AND DISCUSSION

Tween 80 and TPGS as surfactants and Capmul MCM as oil phase were found to produce stable nanoemulsions. Five formulations of SNEDDS had globule size of 55-60 nm and zeta potential of -4 to -11 mV. Self-emulsification time was between 221 and 370 s, while viscosity was dependent on composition of SNEDDS. Cloud point was above 70°C which indicated the retention of in vivo self-emulsifying properties. Average flux for cefpodoxime proxetil (CP) and SNEDDS was 0.104 and 0.985 µg/cm(2) min. Permeability was 19.72 and 206 for CP and SNEDDS. Liquid SNEDDS spray coated onto micropellets of microcrystalline cellulose (18-20#) were analysed by scanning electron microscope (SEM), self-emulsification and in vitro dissolution. A 5.36-fold increase in area under curve AUC(0-∞) was observed for CP-SNEDDS than plain drug. Minimum inhibitory concentration (MIC) was lower for SNEDDS. Liquid and SNEDDS micropellets were stable under accelerated conditions.

CONCLUSION

SNEDDS formulations led to improved oral bioavailability due to enhanced solubilization of selected drug.

Cefpodoxime proxetil-related hemolysis and acute interstitial nephritis

OBJECTIVE

We report a case of acute interstitial nephritis (AIN) and immune hemolytic anemia (IHA) associated with cefpodoxime therapy.

CASE SUMMARY

A patient with a recent history of cefpodoxime proxetil treatment presented with elevated serum creatinine, oliguria, nausea, vomiting, and dyspnea. Evidence of renal failure, abnormal urinalysis, and renal biopsy with inflammatory infiltrate in the interstitium confirmed a diagnosis of AIN. The patient subsequently developed IHA, which was confirmed by peripheral blood smear results and positive Coombs' test. The patient recovered after dialysis therapy and 2 days of intravenous methylprednisolone (500mg/day) followed by oral prednisolone (60 mg/day), which was rapidly tapered and stopped within 3 weeks.

CONCLUSIONS

To our knowledge, cefpodoxime-induced AIN and IHA are unprecedented. Physicians should be aware that drug-induced AIN and hemolysis can be associated with cefpodoxime proxetil.

Concurrent patient-partner treatment in pregnancy: an alternative to expedited partner therapy?

BACKGROUND

Concurrent patient-partner treatment (CPPT) is the provision of treatment to the index patient and their sexual partner(s) and appears to be an effective method of preventing repeat sexually transmitted infections. The objectives of the study were to determine whether CPPT reduces the prevalence of a positive test of cure (TOC) for chlamydia and/or gonorrhea infection in pregnant women.

METHODS

We conducted an observational cohort study of 241 pregnant women aged 15 to 40 years diagnosed with chlamydia and/or gonorrhea receiving prenatal care at an urban teaching hospital. Pregnant women and their sexual partner(s) received CPPT consisting of azithromycin and/or cefpodoxime for treatment of chlamydia and/or gonorrhea infection, respectively, or patient referral consisting of an antibiotic prescription to the pregnant woman and advice for partner screening and therapy. Odds ratios (ORs) and survival estimates were calculated by χ or Fisher exact test, multivariable logistic regression, and Kaplan-Meier.

RESULTS

Forty-five pregnant women with chlamydia and/or gonorrhea received CPPT and were less likely to have a positive TOC (OR = 0; P < 0.001) and repeat positive chlamydia infection (OR = 0; P = 0.12) compared with 196 women that were treated and counseled on the patient referral treatment strategy for their sexual partners. CPPT shortened the median time to cure (4.4 weeks, standard deviation = 2.3) versus standard patient referral (5.1 weeks, standard deviation = 5.2). There were no repeat positive chlamydia infections in the CPPT group compared with 19 (18.1%) in the patient referral group.

CONCLUSIONS

CPPT decreased the prevalence of a positive TOC for chlamydia infection among pregnant women.

A multicentric, open label, randomised, postmarketing efficacy study comparing multidose of lincomycin hydrochloride capsule 500 mg with multidose cefpodoxime proxetil tablet 200 mg in patients with tonsillitis, sinusitis

Tonsillitis causes considerable short and medium term morbidity, and can be recurrent. Sinusitis can be acute (less than 4 weeks), subacute (4-8 weeks) or chronic (8 weeks or more). To study the comparative efficacy and safety of multidose treatments of lincomycin hydrochloride 500 mg capsules against cefpodoxime proxetil 200 mg tablets on its outcome in the Indian scenario are the aims and objective of the study. A total of 41 tonsillitis, sinusitis cases of either gender aged above 18 years were enrolled in the study. The diagnosis of sonsillitis, sinusitis was made based on examination of symptoms and throat swab. A randomised treatment of either lincomycin hydrochloride 500 mg capsules or cefpodoxime proxetil 200 mg tablets twice daily for five days alongwith other concomitant medications depending on related symptoms was given to 40 patients. At the end of study, all patients were re-evaluated and the response rate was assessed. The most common clinical symptoms were body temperature, headache, throat pain, postnasal discharge, mucopus, odynophagia, sinus tenderness, nasal congestion, pharyngeal congestion and tonsillar congestion. The overall response rate of lincomycin hydrochloride in all the symptoms except headache was more effective than cefpodoxime proxetil. Out of 100% (n = 20) patients in each group, 67.89% in lincomycin and 52.27% in cefpodoxime patients achieved complete relief, in all the clinical symptoms. The study suggests that lincomycin hydrochloride capsules, a conventional antibiotic indicates effective treatment for relief from tonsillitis and sinusitis, as compared to new third generation antibiotic.

Dose escalation of intravenous irinotecan using oral cefpodoxime: a phase I study in pediatric patients with refractory solid tumors

BACKGROUND

Administration of an oral cephalosporin allowed advancement of the dosage of oral irinotecan. This study investigates whether administration of an oral cephalosporin increases the maximum tolerated dose (MTD) of intravenous irinotecan.

PROCEDURE

Irinotecan was administered intravenously on Days 1-5 and Days 8-12 of a 21-day cycle with continuous oral cefpodoxime starting 2 days prior to irinotecan. Cohorts of 3-6 pediatric patients with refractory solid tumors were enrolled at 4 dosage levels, starting at the single-agent irinotecan MTD of 20 mg/m(2) /dose.

RESULTS

The 17 evaluable patients received 39 courses of therapy. None of the patients treated with 20 mg/m(2) /dose experienced dose-limiting toxicity (DLT). One of six patients treated at 30 mg/m(2) /dose experienced dose-limiting neutropenia. Two of three patients treated with 45 mg/m(2) /dose and two of five treated with 40 mg/m(2) /dose experienced dose-limiting diarrhea, with associated dehydration and anorexia. Two unconfirmed partial responses were observed after one course in a patient with Ewing sarcoma and one with paraganglioma. A child with refractory neuroblastoma had disease stabilization through 12 courses of therapy. Median (range) systemic exposure to SN-38 at the MTD (30 mg/m(2) /dose) was 67 ng-h/mL (36 to 111 ng-h/mL).

CONCLUSIONS

The MTD of intravenous irinotecan administered on a protracted schedule was increased by 50% from 20 to 30 mg/m(2) /dose with the addition of oral cefpodoxime. The most prominent DLT remained diarrhea. High interpatient variability in irinotecan pharmacokinetics was observed; however, SN-38 exposure at the MTD was greater than most reported exposures with the 20 mg/m(2) dosage.

Cefpodoxime vs ciprofloxacin for short-course treatment of acute uncomplicated cystitis: a randomized trial

CONTEXT

Although fluoroquinolones remain the most reliable urinary antimicrobial, resistance rates have increased and effective fluoroquinolone-sparing antimicrobials are needed.

OBJECTIVE

To determine whether cefpodoxime is noninferior to ciprofloxacin for treatment of acute cystitis.

DESIGN, SETTING, AND PATIENTS

Randomized, double-blind trial of 300 women aged 18 to 55 years with acute uncomplicated cystitis comparing ciprofloxacin (n = 150) with cefpodoxime (n = 150); patients were from a student health center in Seattle, Washington, and a referral center in Miami, Florida. The study was conducted from 2005 to 2009 and outcomes were assessed at 5 to 9 days and 28 to 30 days after completion of therapy. Intent-to-treat and per-protocol analyses were performed; 15 women in the ciprofloxacin group and 17 women in the cefpodoxime group were lost to follow-up.

INTERVENTIONS

Patients were given 250 mg of ciprofloxacin orally twice daily for 3 days or 100 mg of cefpodoxime proxetil orally twice daily for 3 days.

MAIN OUTCOME MEASURES

Overall clinical cure (defined as not requiring antimicrobial treatment during follow-up) at the 30-day follow-up visit. Secondary outcomes were clinical and microbiological cure at the first follow-up visit and vaginal Escherichia coli colonization at each follow-up visit. The hypothesis that cefpodoxime would be noninferior to ciprofloxacin by a 10% margin (ie, for the difference in the primary outcome for ciprofloxacin minus cefpodoxime, the upper limit of the confidence interval would be <10%) was formulated prior to data collection.

RESULTS

The overall clinical cure rate at the 30-day visit with the intent-to-treat approach in which patients lost to follow-up were considered as having clinical cure was 93% (139/150) for ciprofloxacin compared with 82% (123/150) for cefpodoxime (difference of 11%; 95% CI, 3%-18%); and for the intent-to-treat approach in which patients lost to follow-up were considered as having not responded to treatment, the clinical cure rate was 83% (124/150) for ciprofloxacin compared with 71% (106/150) for cefpodoxime (difference of 12%; 95% CI, 3%-21%). The microbiological cure rate was 96% (123/128) for ciprofloxacin compared with 81% (104/129) for cefpodoxime (difference of 15%; 95% CI, 8%-23%). At first follow-up, 16% of women in the ciprofloxacin group compared with 40% of women in the cefpodoxime group had vaginal E coli colonization.

CONCLUSIONS

Among women with uncomplicated cystitis, a 3-day regimen of cefpodoxime compared with ciprofloxacin did not meet criteria for noninferiority for achieving clinical cure. These findings, along with concerns about possible adverse ecological effects associated with other broad-spectrum β-lactams, do not support the use of cefpodoxime as a first-line fluoroquinolone-sparing antimicrobial for acute uncomplicated cystitis.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00194532.

Pharmacokinetics of cefpodoxime in plasma and subcutaneous fluid following oral administration of cefpodoxime proxetil in male beagle dogs

Pharmacokinetics of cefpodoxime in plasma (total concentration) and subcutaneous fluid (free concentration using microdialysis) was investigated in dogs following single oral administration of prodrug cefpodoxime proxetil (equivalent to 5 and 10 mg/kg of cefpodoxime). In a cross over study design, six dogs per dose were utilized after a 1 week washout period. Plasma, microdialysate, and urine samples were collected upto 24 h and analyzed using high performance liquid chromatography. The average maximum concentration (C(max) ) of cefpodoxime in plasma was 13.66 (±6.30) and 27.14 (±4.56) μg/mL with elimination half-life (t(1/2) ) of 3.01 (±0.49) and 4.72 (±1.46) h following 5 and 10 mg/kg dose, respectively. The respective average area under the curve (AUC(0-∞) ) was 82.94 (±30.17) and 107.71 (±30.79) μg·h/mL. Cefpodoxime was readily distributed to skin and average free C(max) in subcutaneous fluid was 1.70 (±0.55) and 3.06 (±0.93) μg/mL at the two doses. Urinary excretion (unchanged cefpodoxime) was the major elimination route. Comparison of subcutaneous fluid concentrations using pharmacokinetic/pharmacodynamic indices of fT(>MIC) indicated that at 10 mg/kg dose; cefpodoxime would yield good therapeutic outcome in skin infections for bacteria with MIC(50) upto 0.5 μg/mL while higher doses (or more frequent dosing) may be needed for bacteria with higher MICs. High urine concentrations suggested cefpodoxime use for urinary infections in dogs.

Pharmacokinetics of cefpodoxime proxetil with special reference to biochemical parameters, tissue residue, and spermatozoa motility in rats

BACKGROUND

Cefpodoxime is a semisynthetic third generation cephalosporin analogue with a relatively broader spectrum of antimicrobial activity against gram negative and gram positive organisms. This is attributed to their somewhat increased resistance to degradation by the betalactamase. Cefpodoxime shows good activity against Klebsiella pneumonia, many members of enterobactericeae and almost all strains of Escherichia coli. It is extensively used in human beings against infections caused by susceptible organisms for a prolonged period and even without its judicious indication. Though various researchers have worked on the pharmacokinetic aspects of the drug, its effects on biochemical parameters and spermatozoa activity are scarcely available in literature.

AIM

To determine the oral kinetic ( blood and tissue) after single therapeutic dose of cefpodoxime proxetil (20mg/kg oral bid 7 days) in rats of either sex on tissue half life and certain biochemical parameters such as glucose, hemoglobin, protein, ALT, AST and other parameters like tissue residue, sperm count and spermatozoa motility in male rats.

MATERIALS AND METHODS

For kinetic studies,24 Wister rats of either sex, 3 months of age, (180-210 gm) were used.(Group I-IV; n=6) Blood samples collected from each animal of Group IV through heart puncture at 0 hour to serve as predrug control. All the group (I-IV) received cefpodoxime proxetil 20 mg/kg once orally as a single dose. At the end of 1,4,12 and 24 hour post oral administration, GroupI,II,III and IVwere utilized for kinetic studies. Blood samples were collected from each animal and vital organs viz brain, lung, liver, spleen, kidney and heart were dissected out for drug analysis and determination of weight. For biochemical parameters, tissue residue and spermatozoa motility, twelve male rats were randomly divided into Groups A and B (n=6) Group B received cefpodoxime (20mg/kg orally bid 7 days) while Group A served as control. Biochemical parameters [Blood glucose, protein, Aspartate transaminase(AST), Alanine transaminase(ALT)and hemoglobin] were measured at 0 and 7 th day while sperm count (total,live and dead)and mean organ weight (study and control group) and tissue residue of drug were evaluated at the end of treatment. Absorption of cefpodoxime was observed at 2 hour and reached a maximum at 4 hour and persisted in blood till 24 hour. Elimination half life in lung was highest followed by heart, liver, kidney and spleen while t½ k in plasma was very low suggesting more affinity of cefpodoxime for tissues than blood.

RESULTS AND CONCLUSION

Blood glucose, protein, AST and ALT activities were not significantly altered but the hemoglobin level and total and live sperm count decreased significantly in the study group compared to the control group. Residual level of cefpodoxime was highest in liver followed by kidney and other study organs. Therefore, the drug should be used in human beings judiciously and further study on human subjects is warranted.

Pharmacokinetics, protein binding, and tissue distribution of orally administered cefpodoxime proxetil and cephalexin in dogs

OBJECTIVE

To determine the effect of protein binding on the pharmacokinetics and distribution from plasma to interstitial fluid (ISF) of cephalexin and cefpodoxime proxetil in dogs.

ANIMALS

6 healthy dogs.

PROCEDURES

In a crossover study design, 25 mg of cephalexin/kg or 9.6 mg of cefpodoxime/kg was administered orally. Blood samples were collected before (time 0) and 0.33, 0.66, 1, 2, 3, 4, 6, 8, 10, 12, 16, and 24 hours after treatment. An ultrafiltration device was used in vivo to collect ISF at 0, 2, 4, 6, 8, 10, 12, 16, and 24 hours. Plasma and ISF concentrations were analyzed with high-pressure liquid chromatography. Plasma protein binding was measured by use of a microcentrifugation technique.

RESULTS

Mean plasma protein binding for cefpodoxime and cephalexin was 82.6% and 20.8%, respectively. Mean ± SD values for cephalexin in plasma were determined for peak plasma concentration (Cmax, 31.5±11.5 μg/mL), area under the time-concentration curve (AUC, 155.6±29.5 μg•h/mL), and terminal half-life (T½, 4.7±1.2 hours); corresponding values in ISF were 16.3±5.8 μg/mL, 878±21.0 μg•h/mL, and 3.2±0.6 hours, respectively. Mean±SD values for cefpodoxime in plasma were 33.0±6.9 μg/mL (Cmax), 282.8±44.0 μg•h/mL (AUC), and 5.7±0.9 hours (T1/2); corresponding values in ISF were 4.3±2.0 μg/mL, 575±174 μg•h/mL, and 10.4±3.3 hours, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Tissue concentration of protein-unbound cefpodoxime was similar to that of the protein-unbound plasma concentration. Cefpodoxime remained in tissues longer than did cephalexin.

Enhancement of bioavailability of cefpodoxime proxetil using different polymeric microparticles

Poorly water-soluble drugs such as cefpodoxime proxetil (400 μg/ml) offer a challenging problem in drug formulation as poor solubility is generally associated with poor dissolution characteristics and thus poor oral bioavailability. According to these characteristics, preparation of cefpodoxime proxetil microparticle has been achieved using high-speed homogenization. Polymers (methylcellulose, sodium alginate, and chitosan) were precipitated on the surface of cefpodoxime proxetil using sodium citrate and calcium chloride as salting-out agents. The pure drug and the prepared microparticles with different concentrations of polymer (0.05-1.0%) were characterized in terms of solubility, drug content, particle size, thermal behavior (differential scanning calorimeter), surface morphology (scanning electron microscopy), in vitro drug release, and stability studies. The in vivo performance was assessed by pharmacokinetic study. The dissolution studies demonstrate a marked increase in the dissolution rate in comparison with pure drug. The considerable improvement in the dissolution rate of cefpodoxime proxetil from optimized microparticle was attributed to the wetting effect of polymers, altered surface morphology, and micronization of drug particles. The optimized microparticles exhibited excellent stability on storage at accelerated condition. The in vivo studies revealed that the optimized formulations provided improved pharmacokinetic parameter in rats as compared with pure drug. The particle size of drug was drastically reduced during formulation process of microparticles.

Physicochemical and pharmacokinetic characterization of a spray-dried cefpodoxime proxetil nanosuspension

Cefpodoxime proxetil (CP) is a prodrug, the third generation cephem-type broad-spectrum antibiotic administered orally. However, CP was found to be a poorly water-soluble drug with low bioavailability when orally administered. In the present investigation, the spray-dried cefpodoxime proxetil nanosuspension (SDN) was prepared. The physicochemical properties were characterized by rheological evaluation, particle size measurement and its distribution, dynamics of reconstitution, in-vitro dissolution testing, surface morphology, surface area and pore size measurements. The pharmacokinetic study of SDN, in comparison to a marketed cefpodoxime proxetil for oral suspension (MS), was also performed in rabbits after a single oral dose. It was found that SDN exhibited a significant decrease in t(max), a 1.60-fold higher area under curve (AUC) and 2.33-fold higher maximum plasma concentration (C(max)) than MS.

Switch therapy in full-term neonates with presumed or proven bacterial infection

This case-control study of full-term newborns with presumed or proven bacterial infection compared the efficacy, safety and tolerability of switch antibiotic therapy and traditional completely intravenous antibiotic administration. there were 36 newborns treated with switch therapy (i.v. ampicillin + sulbactam combined with i.v. amikacin for 3 days followed by oral cefpodoxime proxetil for 5 days); there were 72 full-term newborns with the same characteristics as controls who received i.v. ampicillin + sulbactam combined with i.v. amikacin for 3 days followed by i.v. ampicillin + sulbactam alone for a further 5 days. the results showed that full-term newborns with presumed or proven bacterial infection initially treated with intravenous antibiotics can be switched to oral antibiotics after 3 days' therapy if physical and laboratory data indicate the disappearance of infection, thus significantly reducing the length of stay in the neonatal intensive care unit and significantly increasing breastfeeding, without having any negative clinical impact.

The comparative plasma pharmacokinetics of intravenous cefpodoxime sodium and oral cefpodoxime proxetil in beagle dogs

The pharmacokinetic properties of cefpodoxime, and its prodrug, cefpodoxime proxetil, were evaluated in two separate studies, one following intravenous (i.v.) administration of cefpodoxime sodium and the second after oral (p.o.) administration of cefpodoxime proxetil to healthy dogs. After cefpodoxime administration, serial blood samples were collected and plasma concentrations were determined by high performance liquid chromatography (HPLC). A single i.v. administration of cefpodoxime sodium at a dose of 10 mg cefpodoxime/kg body weight resulted in a cefpodoxime average maximum plasma concentration (Cmax) of 91 (+/-17.7) microg/mL, measured at 0.5 h after drug administration, an average half-life (t1/2) of 4.67 (+/-0.680) h, an average AUC(0-infinity) of 454 (+/-83.1) h.microg/mL, an average V(d(ss)) of 151 (+/-27) mL/kg, an average Cl(B) of 22.7 (+/-4.2) mL/h/kg and an average MRT(0-infinity) of 5.97 (+/-0.573) h. When dose normalized to 10 mg cefpodoxime/kg body weight, cefpodoxime proxetil administered orally resulted in Cmax of 17.8 +/- 11.4 microg/mL for the tablet formulation and 20.1 +/- 6.20 microg/mL for the suspension formulation and an average AUC(0-LOQ) of 156 (+/-76.1) h.microg/mL for the tablet formulation and 162 (+/-48.6) h.microg/mL for the suspension formulation. Relative bioavailability of the two oral formulations was 1.04 (suspension compared with tablet), whereas the absolute bioavailability of both oral formulations was estimated to be approximately 35-36% in the cross-study comparison with the i.v. pharmacokinetics. Combined with previous studies, these results suggest that a single daily oral dose of 5-10 mg cefpodoxime/kg body weight as cefpodoxime proxetil maintains plasma concentrations effective for treatment of specified skin infections in dogs.

Effect of dosing and dosing frequency on the efficacy of ceftizoxime and the emergence of ceftizoxime resistance during the early development of murine abscesses caused by Bacteroides fragilis and Enterobacter cloacae mixed infection

The efficacy of beta-lactams is thought to be dependent on the time that the unbound concentrations exceed the MIC (fT>MIC). However, the pharmacokinetic/pharmacodynamic index (PDI) that correlates best to the selection of resistance is not yet clear. The selection of ceftizoxime (CZX)-resistant Enterobacter cloacae mutant strains during the development of murine mixed-infection abscesses was studied to determine the PDI that is important for the emergence of resistance and the PDI value needed for the prevention of resistance. Studies were carried out 24 h after inoculation with Bacteroides fragilis ATCC 23745 and E. cloacae 22491. Six to 1,536 mg of CZX/kg of body weight/day given every 2 h (q2h), q4h, q6h, or q8h was started 30 min before inoculation and continued for 24 h. Resistant mutants were isolated to determine mutant frequencies (MF). The fT>MIC varied from 9 to 98% for E. cloacae, the peak concentration (unbound fraction) was 0.6 to 578 mg/liter, and the area under the concentration-time curve (unbound fraction) (fAUC) was 1.9 to 553 mg.h/liter. The fAUC-to-MIC ratio best explained the in vivo efficacy. CZX-resistant B. fragilis and E. cloacae mutants were isolated from untreated controls at an MF of 10(-5) to 10(-7). The MF of resistant B. fragilis did not increase during therapy. The selection of resistant E. cloacae strains at an MF of 10(-1) to 10(-2) was related to the fT>MIC and the ratio of fAUC to MIC following an inverse U shape. However, the ratio of fAUC to MIC was the stronger driver of resistance. The highest MFs were 0.7 to 0.9 at an fAUC-to-MIC ratio of approximately 250. We conclude that the ratio of fAUC to MIC is the PDI that correlated best to the in vivo efficacy of CZX and probably also to the emergence of resistant E. cloacae mutants. An fAUC-to-MIC ratio of 1,000 was needed to prevent the emergence of this resistance.

Design and evaluation of self-nanoemulsifying drug delivery systems (SNEDDS) for cefpodoxime proxetil

Self-nanoemulsifying drug delivery systems (SNEDDS) were developed with the objective to overcome problems associated with the delivery of cefpodoxime proxetil (CFP), a poorly bioavailable high dose antibiotic having pH dependant solubility. Solubility of CFP in oily phases and surfactants was determined to identify components of SNEDDS. Various surfactants and co-surfactants were screened for their ability to emulsify selected oily phases. Ternary phase diagrams were constructed to identify area of nanoemulsification for the selected systems. The influence of CFP and the pH of dilution medium on the phase behavior of selected system were assessed. The globule size of optimized CFP SNEDDS in various dissolution media was determined to check the effect of pH on its behavior. The optimized CFP SNEDDS needed surfactant content less than 40% and yielded nanoemulsion of mean globule size 170 nm, which was not affected by the pH of dilution medium. The optimized SNEDDS released CFP completely within 20 min irrespective of the pH of dissolution medium.

Investigation on physicochemical and biological differences of cefpodoxime proxetil enantiomers

Cefpodoxime proxetil (CP) is a prodrug of cefpodoxime acid (CA), and is supplied as racemic mixture of R- and S-enantiomers. CP has only 50% absolute bioavailability, and the reasons responsible for low bioavailability remain poorly understood. The present work ascertains physicochemical and biological properties of individual isomers of CP and explores their capacity to optimize delivery of CP. Both isomers showed similar pH stability behavior, but R-isomer was more susceptible to enzymatic metabolism compared to S-isomer, when incubated with enzymes collected from various segments of GIT. Based on the in vitro and in vivo results, use of S-isomer for development of a dosage form such as gastro-retentive dosage form can improve oral bioavailability of CP.

Once-daily tablet formulation and in vitro release evaluation of cefpodoxime using hydroxypropyl methylcellulose: a technical note

Decreasing the dose frequency of cefpodoxime proxetil increases patient compliance; patients prefer to take the drug once daily. It also improves the rate of bacterial killing and hastens the cure from the indications, and therefore increases compliance. The hydrophilic matrix of HPMC controlled the cefpodoxime proxetil release effectively for 24 hours; hence, the formulation can be considered as a once-daily sustained-release tablet of cefpodoxime proxetil. The formulation showed acceptable pharmacotechnical properties and assay requirements. In vitro dissolution studies indicated a sustained-release pattern throughout 24 hours of the study that was comparable to the theoretical release profile. Drug release kinetics indicated that drug release was best explained by Higuchi’s equation, as these plots showed the highest linearity (r 2=0.9734), but a close relationship was also noted with zero-order kinetics (r 2=0.9708). Korsmeyer’s plots indicated ann value of 0.57, which was indicative of an anomalous diffusion mechanism or diffusion coupled with erosion; hence, the drug release was controlled by more than one process. Hixson-Crowell plots indicated a change in surface area and diameter of the tablets with the progressive dissolution of the matrix as a function of time.

[Treatment of acute maxillary sinusitis in adults. Comparison of cefpodoxime-proxetil and amoxicillin-clavulanic acid]

OBJECTIVE

The aim was to demonstrate the equivalence of the clinical efficacy and safety of cefpodoxime-proxetil (200 mg bid for 5 days) to that of amoxicillin-clavulanic acid (1 g/125 mg bid for 8 days) in adults with acute maxillary sinusitis.

METHOD

In this prospective, multicenter, centrally-randomized, open-label study, 73 general practitioners and 11 ear, nose, and throat specialists included 512 patients with unilateral acute maxillary sinusitis.

RESULTS

The clinical success rates at day 12-19 in the per-protocol population (primary analysis) were 92.3% (215/233) in the cefpodoxime-proxetil group and 93.6% (204/218) in the amoxicillin-clavulanic acid group. The 95% confidence interval of [6.5%; 3.9%] demonstrated that cefpodoxime-proxetil was not inferior to amoxicillin-clavulanic acid. Cure rates at follow-up (day 25-30) were 90.6% and 92.7%, respectively. Results were similar in the intent-to-treat population. Compliance was significantly better in the cefpodoxime-proxetil group (99.2% versus 95.5%; p=0.011). Tolerance was also significantly better: 1.2% (3/247) of cefpodoxime-proxetil patients reported a treatment-related adverse event, compared with 10.7% (26/244) in the amoxicillin-clavulanic acid group (p<0.001). Most events were gastrointestinal and of mild to moderate intensity.

CONCLUSION

In this study, a 5-day course of cefpodoxime-proxetil at 200 mg bid was as clinically effective as amoxicillin-clavulanic acid 1 g/125 mg bid for 8 days with a significantly better safety profile and compliance.

Tissue penetration of cefpodoxime into the skeletal muscle and lung in rats

PURPOSE

The aim of this study was to investigate the pharmacokinetics of cefpodoxime in interstitial tissue fluids (skeletal muscle and lung) in rats by microdialysis, and to examine the relationship between free drug levels in plasma and in tissues.

METHODS

Cefpodoxime was administered to anesthetized male Wistar rats as single intravenous bolus of 10 or 20 mg/kg and constant infusion of 260 microg/h with a loading dose. The protein binding of cefpodoxime in rat plasma was determined using ultrafiltration.

RESULTS

The average protein binding of cefpodoxime in rat plasma was 38%. The half-lives in plasma, muscle and lung were similar (approximately 5 h). After constant rate infusion, the free concentrations in the muscle and the lung were almost identical, but lower than total and free plasma concentrations. The data were modeled simultaneously using a two-compartmental body model.

CONCLUSIONS

Free interstitial levels of cefpodoxime in muscle and lung tissue are very similar. Since muscle is more accessible than lung, free muscle concentrations may serve as a good surrogate for unbound concentrations in lung.

Disposition of orally administered cefpodoxime proxetil in foals and adult horses and minimum inhibitory concentration of the drug against common bacterial pathogens of horses

OBJECTIVES

To determine the disposition of orally administered cefpodoxime proxetil in foals and adult horses and measure the minimum inhibitory concentrations (MICs) of the drug against common bacterial pathogens of horses.

ANIMALS

6 healthy adult horses and 6 healthy foals at 7 to 14 days of age and again at 3 to 4 months of age.

PROCEDURE

A single dose of cefpodoxime proxetil oral suspension was administered (10 mg/kg) to each horse by use of a nasogastric tube. In 7- to 14-day-old foals, 5 additional doses were administered intragastrically at 12-hour intervals. The MIC of cefpodoxime for each of 173 bacterial isolates was determined by use of a commercially available test.

RESULTS

In 7- to 14-day-old foals, mean +/- SD time to peak serum concentration (Tmax) was 1.7 +/- 0.7 hours, maximum serum concentration (Cmax) was 0.81 +/- 0.22 microg/mL, and elimination half-life (harmonic mean) was 7.2 hours. Disposition of cefpodoxime in 3- to 4-month-old foals was not significantly different from that of neonates. Adult horses had significantly higher Cmax and significantly lower Tmax, compared with values for foals. The MIC of cefpodoxime required to inhibit growth of 90% of isolates for Salmonella enterica, Escherichia coli, Pasteurella spp, Klebsiella spp, and beta-hemolytic streptococci was 0.38, 1.00, 0.16, 0.19, and 0.09 microg/mL, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Oral administration at a dosage of 10 mg/kg every 6 to 12 hours would appear appropriate for the treatment of equine neonates with bacterial infections.

Cefoselis, a ?-lactam antibiotic, easily penetrates the blood-brain barrier and causes seizure independently by glutamate release

Cefoselis is a widely used beta-lactam antibiotic, but occasionally induces seizures and convulsion in elder and renal failure patients. However, beta-lactams are known not to pass through the blood-brain barrier (BBB). In this study, we examined the BBB penetration of cefoselis in normal and renal failure rats by means of brain microdialysis. Cefoselis was dose-dependently appeared in brain extracellular fluid in proportion to its blood level. The elimination constant from brain extracellular fluid (apparent) was slightly lower than that from blood. These results indicated that cefoselis might penetrate the BBB or be discharged by a certain transport system. In contrast to the result of cefoselis, cefazolin, a leading drug of cephalosporins, could not be detected in the brain extracellular fluid after an intravenous injection. In renal dysfunction rats, the elimination half-lives of cefoselis from both blood and brain were extensively prolonged. This would be one of responsible factors inducing seizures seen in patients. However, the additional factor, such as decrease in brain function related to aging, would be involved in seizures in patient received cefoselis, because an extremely high dose was required to induce seizures even in renal failure rats. A local administration of cefoselis into the hippocampus through the microdialysis probe caused a striking elevation of extracellular glutamate, with a minimum increase in gamma-aminobutyric acid (GABA). However, a systematic cefoselis administration via the tail vein did not elevate extracellular glutamate and GABA concentrations in the hippocampus of renal failure rats that exhibited marked seizures. These results suggested that not the stimulation of glutamate release, but the blockade of GABA receptors might be responsible for the seizure induced by cefoselis.

Comparative study of the effects of ceftizoxime, piperacillin, and piperacillin-tazobactam concentrations on antibacterial activity and selection of antibiotic-resistant mutants of Enterobacter cloacae and Bacteroides fragilis in vitro and in vivo in mixed-infection abscesses

The effects of ceftizoxime (CZX), piperacillin (PIP), and PIP-tazobactam (PT) concentrations on the antibacterial activity and selection of resistant mutants of Bacteroides fragilis and Enterobacter cloacae were investigated in vitro in a mixed-culture anaerobic time-kill study and in vivo in a mixed-infection abscess model. Mixed cultures were incubated for 24 h with 0.125 to 512 micro g of CZX per ml or 0.125 to 2,048 micro g of PIP or PT per ml. Mice were treated every 2 h for 24 h with CZX at 6 to 1,536 mg/kg/day or with PIP or PT at 24 to 6,144 mg/kg/day starting 30 min before inoculation with different B. fragilis-E. cloacae combinations. There was a good correlation between the in vitro and in vivo activities of the antibiotics and their MICs obtained with high inocula (10(8) CFU/ml). The respective 50% effective doses (milligrams per kilogram per day) with B. fragilis and E. cloacae 22491 were 771 and 521 for CZX, 416 and 643 for PIP, and 85 and 554 for PT, and with the B. fragilis-E. cloacae 032349 combination, they were 81 and 21 for CZX and 77 and 766 for PT. Resistant mutants of E. cloacae 22491 were preferentially selected in vitro with 2 to 64 micro g of CZX per ml and in vivo with CZX at 12 to 384 mg/kg/day. There was no preferential selection of CZX-resistant B. fragilis or E. cloacae 032349. For CZX-resistant E. cloacae 22491, we found a 16- to 512-fold increase in the MIC of CZX and increased MICs of other expanded-spectrum cephalosporins, owing in part to the production of a stably derepressed cephalosporinase. In vitro and in vivo, PT did not select resistant mutants of E. cloacae and B. fragilis. Results demonstrate the adverse microbiological outcome of choosing an expanded-spectrum cephalosporin like CZX for empirical treatment of mixed infections involving a susceptible Enterobacter strain.

Improvement of cefpodoxime proxetil oral absorption in rats by an oil-in-water submicron emulsion

Absolute bioavailability of cefpodoxime proxetil is both limited by its low solubility in aqueous solution and its intraluminal hydrolysis. The oil-in-water submicron emulsion was proven to be effective in protecting the prodrug from the enzymatic attack in rabbit intestinal washings. The aim of the study was to perform a pharmacokinetic study in conscious rats to confirm o/w submicron superiority in comparison to other oral formulations (hydro-alcoholic solution, suspension and coarse emulsion). The pharmacokinetic study was performed in conscious rats implanted with permanent aortic catheters. A parenteral solution of cefpodoxime was injected via this catheter, and oral formulations were administered orally. The cefpodoxime plasma level was performed by a HPLC validated method. The pharmacokinetic parameters, t1/2, Cmax, tmax, AUC and absolute bioavailability (F) were determined with a non-compartmental analysis. The results show a significant increase of F for submicron emulsion (97.4%) between the other oral formulations. No significant difference of F was found between the other oral formulations, even with the coarse o/w emulsion. The o/w submicron emulsion made the enhancement of the absolute bioavailability of cefpodoxime proxetil possible. This benefit could be explained by the low droplet size of the submicron emulsion which improve the absorption process of the prodrug.

A multicentric study to evaluate efficacy and safety of cefetamet pivoxyl in lower respiratory tract infections in Indian patients

This multicentric, open label, non-comparative study was designed to evaluate the extended spectrum of third generation oral cephalosporin, cefetamet pivoxyl in the treatment of patients with lower respiratory tract infections. This study was conducted among 111 patients with clinical, radiological and bacteriological findings consistent with the diagnosis. After obtaining written informed consent, patients were given cefetamet 500 mg tablet twice a day for 7 days. Cefetamet consistently decreased all clinical signs and symptoms at post-therapy visit. All the treated patients were either cured or improved. Cefetamet was well tolerated with a low incidence of drug related adverse events. The findings of this study indicate that cefetamet pivoxyl was well tolerated and is suitable option for the treatment of patients with lower respiratory tract infection.

Intracerebroventricular injection of the antibiotic cefoselis produces convulsion in mice via inhibition of GABA receptors

A majority of beta-lactam antibiotics (e.g., cephalosporins and penicillins) have convulsive activity to a greater or lesser extent. (6R,7R)-3-[[3-Amino-2-(2-hydroxyethyl)-2H-pyrazol-1-ium-1-yl]methyl]-7-[(Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetylamino]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate monosulfate (cefoselis), a newly developed injectable beta-lactam antibiotic with activity against methicillin-resistant Staphylococcus aureus (MRSA), might induce convulsions if cerebral concentrations become highly elevated. In the present study, we examined whether or not cefoselis had convulsive activity after direct brain administration, and we attempted to clarify the pharmacological mechanism of action. When cefoselis was injected into the lateral ventricle of the mouse brain at doses higher than 20 microg/animal, it produced convulsions dose-dependently. Cefoselis (50 microg/animal)-induced convulsions were prevented by pretreatment with 5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801), diazepam and phenobarbital (ED(50) values (mg/kg) of 0.78, 1.59 and 33.0, respectively), but not by carbamazepine or phenytoin. When the effects of these anticonvulsants on the convulsions induced by intracerebral injection of bicuculline methiodide (BMI) or N-methyl-D-aspartate (NMDA) were investigated, the inhibitory profile of anticonvulsants on cefoselis-induced convulsions was similar to those induced by BMI (125 ng/animal) but differed markedly in their inhibitory activity on NMDA (100 ng/animal)-induced convulsions, which were not inhibited by diazepam. These results suggest that cefoselis may be convulsive at higher concentrations through a mechanism involving inhibition of gamma-aminobutyric acid (GABA)(A) receptors.

Spinal epidural abscess successfully treated with percutaneous, computed tomography-guided, needle aspiration and parenteral antibiotic therapy: case report and review of the literature

OBJECTIVE AND IMPORTANCE

We describe a case of a posterior spinal epidural abscess that was successfully treated with percutaneous, computed tomography-guided, needle aspiration and parenteral antibiotic therapy.

CLINICAL PRESENTATION

A 48-year-old man experienced acute pain in the paralumbar region for 1 week, followed by gait disturbance and micturition difficulty. Laboratory studies demonstrated leukocytosis and hyperglycemia. Blood cultures yielded Staphylococcus aureus. Magnetic resonance imaging scans of the thoracolumbar spine revealed a posterior spinal epidural abscess located between L2 and the lower cervical spine.

INTERVENTION

The patient's low back pain persisted despite 10 days of antibiotic therapy. Therefore, percutaneous, computed tomography-guided, needle aspiration was performed. The low back pain was relieved dramatically and immediately after the procedure. The spinal epidural abscess completely resolved after 6 weeks of antibiotic treatment.

CONCLUSION

Surgical decompression and antibiotic therapy are the treatments of choice for patients with spinal epidural abscesses. Selected patients may be treated nonsurgically. Rarely, percutaneous drainage of the abscess has been reported to be helpful. Our case suggests that percutaneous, computed tomography-guided, needle aspiration might be a rational alternative to surgical decompression for treatment of spinal epidural abscesses.

Interstitial tissue concentrations of cefpodoxime

Microdialysis is a technique that allows the measurement of concentrations of free antibiotic in tissue. The free antibiotic concentration is responsible for the antibacterial effect at the target site. We used microdialysis in animal and human studies to investigate the tissue penetration of cefpodoxime. In the animal study, total plasma and free muscle and lung concentrations of cefpodoxime were measured after male Wistar rats had received either 10 mg/kg or 20 mg/kg i.v. cefpodoxime over 5 h or a continuous i.v. infusion of 260 microg/h cefpodoxime after a loading dose of 6 mg/kg. Free muscle concentrations of cefpodoxime were similar to free lung concentrations and therefore provided a surrogate measure of cefpodoxime concentrations at the pulmonary target site. In an open, randomized, two-way crossover, single-dose study in six healthy male volunteers, total plasma and free muscle concentrations were measured after a single oral dose of cefpodoxime 400 mg or cefixime 400 mg. The total plasma concentrations of each antibiotic were similar and higher than free muscle concentrations. The tissue penetration of cefpodoxime was, however, greater than that of cefixime, as shown by two-fold higher peak free muscle concentrations after dosing with cefpodoxime than with cefixime (2.1 mg/L versus 0.9 mg/L). In addition, the area under the curve for tissue (AUC(t)) of cefpodoxime (400 mg) was more than double that of cefixime (400 mg), based on free antibiotic concentrations (15.4 mg x h/L versus 7.3 mg x h/L). These findings indicate that, taking into account pharmacokinetic/pharmacodynamic considerations, cefpodoxime is likely to be more efficacious than cefixime, due to its greater tissue penetration.

The excretion of cephem antibiotics into saliva is inversely associated with their plasma protein-binding activities

BACKGROUND

The excretion of medicated drugs into saliva may disturb the oral environment and antibiotic excretion into saliva appears to be regulated by many factors that have not been fully explored.

METHODS

Excretion of four cephem antibiotics into saliva was examined in healthy volunteers and rats, using high-performance liquid chromatography, and the relationship between excretion levels and plasma protein-binding activities of the antibiotics was investigated.

RESULTS

Following addition of 50 microgram/ml of each antibiotic to human plasma, protein binding rates (PBRs) of cefuzonam (CZON, molecular weight (MW): 535.58), cefotaxime (CTX, MW: 477.45), flomoxef (FMOX, MW: 518.45) and cefozopran (CZOP, MW: 551.99) were 87.8 +/- 1.2, 70.8 +/- 0.8, 36.2 +/- 0.5 and 8.3 +/- 0.3%, respectively. In rat plasma, PBRs of the four antibiotics were 94.0 +/- 0.5, 62.1 +/- 1.4, 54.0 +/- 0.8 and 6.0 +/- 0.8%, respectively. Similar PBRs were observed when the antibiotic concentration was increased to 100 and 200 microgram/ml. CZOP was most rapidly excreted into saliva and had the highest concentration in saliva among the tested antibiotics, while the plateau level of CZON was the lowest. The excreted levels of each antibiotic in saliva, when locally perfused through the rat facial artery, were inversely associated with each PBR. Similarly, the ratios of antibiotic concentration in saliva to rat plasma were almost constant for each antibiotic, revealing an inverse relationship with PBRs.

CONCLUSION

These results appear to indicate that low molecular weight antibiotics are excreted into saliva through passive diffusion, inversely relating to their PBRs, and that high concentrations of antibiotics in the saliva have the potential to change the oral ecological environment.

Linezolid versus ceftriaxone/cefpodoxime in patients hospitalized for the treatment of Streptococcus pneumoniae pneumonia

Intravenous (i.v.) to oral linezolid (600 mg twice daily for both, with optional aztreonam) and a cephalosporin regimen (i.v. ceftriaxone 1 g twice daily followed by oral cefpodoxime 200 mg twice daily) were compared for the treatment of community-acquired pneumonia (CAP), with emphasis on patients with Streptococcus pneumoniae. This multicenter, randomized, open-label trial was conducted in 27 countries in 6 continents. Efficacy was assessed 12-28 d following treatment. Clinical and laboratory safety assessments were evaluated; isolates for microbiologic assessments were identified primarily by sputum or blood culture. In all treated patients (linezolid, n = 381; ceftriaxone/cefpodoxime, n = 366), linezolid had a higher clinical cure rate than ceftriaxone/cefpodoxime (83.0% vs. 76.4%, respectively; p = 0.040). S. pneumoniae was isolated in 73.2% (186/254) of patients at baseline, with similar eradication rates in the linezolid and ceftriaxone/cefpodoxime groups (88.7% vs. 89.9%, respectively; p = 0.830). Linezolid had a superior clinical cure rate (93.1% vs. 68.2%; p = 0.021) in patients with S. pneumoniae bacteremia. Logistic regression analyses revealed that linezolid-treated patients with bacteremia, pleural effusion, cardiac comorbidities, diabetes or abnormal white blood cell counts had significantly better outcomes than cephalosporin-treated patients. Both regimens were well tolerated, although the incidence of drug-related adverse events was higher in the linezolid group than in the ceftriaxone/cefpodoxime group (21.3% vs. 11.2%, respectively; p = 0.0002). In summary, empiric i.v./oral linezolid was more effective than ceftriaxone/cefpodoxime in patients hospitalized with CAP, with comparable cure rates in S. pneumoniae pneumonia and higher cure rates in pneumonia complicated by bacteremia.

AS-924, a novel, orally active, bifunctional prodrug of ceftizoxime: physicochemical properties, oral absorption in animals, and antibacterial activity

AS-924 is an oral prodrug of the antibiotic ceftizoxime (CTIZ), a parenteral use cephalosporin. This novel prodrug, produced by esterifying CTIZ with a lipophilic pivaloyloxymethyl (POM) group and introducing a water soluble L-alanyl group, is expected to increase the bioavailability and thereby, augment the antibacterial activity of CTIZ in vivo compared with existing prodrugs. To study the effect of the L-alanyl group in AS-924 on its bioavailability, the plasma concentration profiles of CTIZ in dogs were examined following the dosing of AS-924 and CTIZ-POM, in powder form, after pretreatment with the antacid ranitidine, and following the dosing of AS-924 after pretreatment with a gastrointestinal motility stimulant metoclopramide or suppressant scopolamine butylbromide. The absorption rate of AS-924 was constant under these different conditions due to its unique balance of lipophilicity and water solubility. CTIZ is as antibacterially active as pre-existing oral cephalosporins against Gram-positive clinical isolates, while being more active against all Gram-negative isolates-particularly Enterobacteriaceae and Haemophilus influenzae. A simulation model for the eradication profile of bacteria in computer programmed pharmacokinetic (PK) system was carried out to study the antibacterial action of CTIZ in human. CTIZ was proven to eradicate Streptococcus pneumoniae and H. influenzae effectively, while cefpodoxime (CPOD), the active moiety of CPOD proxetil, eradicated S. pneumoniae, but not H. influenzae. These results confirm that, AS-924 is a potent oral antibiotic and would be expected to be clinically effective and efficient.

Effects of food intake and age on the pharmacokinetics of AS-924, a novel ester-type cephem antibiotic. Comparison with cefpodoxime proxetil

The effects of food intake and age on intestinal absorption of AS-924, a novel prodrug-type cephem antibiotic, were examined in 16 healthy adult volunteers (eight young volunteers and eight elderly volunteers) by the cross-over method, using cefpodoxime proxetil (CPOD-PR) as the control drug. The gastrointestinal absorption of AS-924 and CPOD-PR was increased slightly by food intake and the extent of increase was slightly greater after administration of CPOD-PR. The absorption of AS-924 was not affected by age, whereas intestinal absorption of CPOD-PR increased with age. In conclusion, these results confirmed that AS-924 has the unique characteristics as a novel prodrug and that its absorption is less likely to be affected by food intake and age.