Cephalexin Concentration Research Articles

Optimization the Effects of Physicochemical Parameters on the Degradation of Cephalexin in Sono-Fenton Reactor by Using Box-Behnken Response Surface Methodology

This work aims to study the degradation process using Sono-Fenton reactor for the treating of pharmaceutical wastewater loaded with cephalexin. The degradation process was tested as a function of pH (3–11), concentration of degradation agent H2O2 (40–80 mg/L), metal catalyst agent Fe2+ (4–12 mg/L), reaction time (up to 100 min), and initial cephalexin concentration (50–100 mg/L). The effects of these parameters were tested and optimized by using Box-Behnken response surface methodology (RSM). All the experiments were performed with exposure to ultrasonic irradiation of a frequency of 130 kHz. According to the ANOVA results with a confidence level of 95%, a high regression and fitting values were obtained between the experimental degradation data of cephalexin and the RSM predicted model. This finding suggests that RSM is an extremely significant and accurate methodology to model the degradation process of cephalexin using Sono-Fenton reactor. Accordingly, the optimum degradation efficiency of 90% was obtained at conditions of pH 3, H2O2 concentration = 60 mg/L, Fe2+ concentration = 8 mg/L, cephalexin concentration = 50 mg/L, and reaction time = 60 min. Thus, the current study demonstrated that the Sono-Fenton reactor can be used effectively as an advanced oxidation treatment unit for degradation of cephalexin under optimized environmental conditions.

Nanocomposite optosensor of dual quantum dot fluorescence probes for simultaneous detection of cephalexin and ceftriaxone

An optosensor based on the fluorescence quenching of two different nanocomposite fluorescence probes was developed for simultaneous detection of cephalexin and ceftriaxone. The nanocomposite fluorescence probes were synthesized by incorporating graphene quantum dots (GQDs) and cadmium telluride quantum dots (CdTe QDs) in a molecularly imprinted polymer (MIP). The MIP-GQDs and MIP-CdTe QDs exhibited high emission fluorescence intensities at 440 and 575 nm, respectively. The mesoporous structure of the MIP layer provided recognition sites specific to the template analytes. At the optimum condition, the fluorescence intensities of the probes were quenched linearly as the concentrations of cephalexin and ceftriaxone increased from 0.10 to 50.0 μg L−1. The very low detection limits were 0.06 and 0.10 μg L−1 for cephalexin and ceftriaxone, respectively. The developed dual nanocomposite fluorescence probes were used for the detection of cephalexin and ceftriaxone in milk samples. The recoveries of cephalexin and ceftriaxone in four spiked milk samples ranged from 83.0 to 98.7% with RSD lower than 8%. This developed nanocomposite optosensor was highly sensitive and selective for trace detection of cephalexin and ceftriaxone in milk samples and produced results that were in good agreement with the results of HPLC analysis of the same samples.

Draft genome sequence of Xenophilus sp. E41 isolated from an activated sludge reactor treating wastewater with high cephalexin concentration.

This study reports the draft genome sequence of Xenophilus sp. E41, a strain resistant to multiple antimicrobials isolated from an activated sludge reactor treating wastewater with a high cephalexin concentration. Genomic DNA of Xenophilus sp. E41 was extracted and sequenced using an Illumina NovaSeq 6000 system. The generated sequence reads were assembled using MEGAHIT in combination with SOAPdenovo. Mauve and CompareM were used to align the Xenophilus sp. E41 genome to other draft genomes of the genus Xenophilus in order to determine their evolutionary relationships. The draft genome was annotated using the Rapid Annotation using Subsystem Technology (RAST) server and the nr database, whilst antimicrobial resistance genes (ARGs) were identified using the SARG 2.0 database, RAST server and nr database. Xenophilus sp. E41, with a genome length of 5919552bp, harbours seven types of ARGs involving resistance to β-lactams, tetracycline, aminoglycosides, sulfonamides, chloramphenicol, teicoplanin and bleomycin. No virulence factors or plasmids were identified. The genome sequence reported here will provide useful information for a better understanding of antimicrobial resistance profiles in this strain and the genus Xenophilus.

Photocatalysis assisted by activated-carbon-impregnated magnetite composite for removal of cephalexin from aqueous solution

The simultaneous presence of antibiotics and bacteria in aqueous media has been recognized as an environmental threat, due to the enhancement of antibiotic resistance of bacteria. We synthesized an activated carbon impregnated magnetite composite (PAC/Fe3O4) and used it for removal of cephalexin (CEX) from aqueous solution via UV system. A series of batch experiments was carried out under various experimental conditions such as pH of solution (3–11), contact time (0–120 min), catalyst dosages (0.1–2 g/L) and initial CEX concentrations (10, 25, 50 and 100 mg/L). Some common isotherm models were used for study of CEX adsorption and finding the best model. In addition, kinetic studies of CEX photocatalytic removal were performed by fitting the experimental data on first-order and second-order models. Results of comparative studies showed that UV+PAC/Fe3O4 and UV+TiO2 systems, compared to UV/Fe3O4, naked Fe3O4, PAC/Fe3O4 and UV only, had more capability of removing CEX from aqueous solution, indicating PAC/Fe3O4 is effectively catalyzed by UV light. Furthermore, increasing catalyst dosages and decreasing initial CEX concentrations led to the enhancing photocatalytic removal of CEX from solution. The obtained results of kinetic studies also represent that among the studied models, second-order model with significant coefficient of correlation (R2) had higher ability than first-order model to fit the data of CEX removal. Finally, the findings of reusability tests, showed that the applied catalyst would be applicable for CEX removal, even after five consecutive cycles.

Photocatalytic Removal of Cephalexin by UV/ZnO Process from Aqueous Solutions

Background and Objectives: Conventional wastewater treatment plants are not able to remove effective drugs, such as antibiotics, so eliminating remaining antibiotics from the environment is important. The purpose of this study was to evaluate the efficacy of UV / ZnO photocatalytic process in removing antibiotic cephalexin from aqueous solutions. Materials and Methods: This is an experimental-applied study that was performed on a batch scale in a laboratory scale. The variables studied in this study included the initial pH of the solution (11, 9, 7, 5, 3), the dose of nanoparticles (1, 75/0, 0.5, 0.25, 0.1, 0.05 grams per liter), Reaction time (60-50-40-30-20-15-55 minutes) and initial concentration of pollutant (100, 50, 25, 10 mg / l) were investigated. Measurement of cephalexin in samples was performed using HPLC apparatus. Results: The results showed that by decreasing pH and reducing the initial concentration of cephalexin and increasing contact time, process efficiency increased. But with increasing nanoparticle dosages up to 0.1 grams per liter, the process efficiency increases and more than this amount is reduced. Conclusion: The results of this study showed that the use of UV / ZnO photocatalytic process in removing humic acid from aqueous solutions can be used as an effective method for cephalexin from aqueous solutions.

Occurrence and fate of most prescribed antibiotics in different water environments of Tehran, Iran

The presence of most prescribed antibiotic compounds from four therapeutic classes (β-lactam, cephalosporins, macrolides, fluoroquinolones) were studied at two full-scale WWTPs, two rivers, thirteen groundwater resources, and five water treatment plants in Tehran. Analytical methodology was based on high performance liquid chromatography/tandem mass spectrometry after solid-phase extraction. Samples were collected at 33 sample locations on three sampling periods over four months from June to August 2016. None of the target antibiotics were detected in groundwater resources and water treatment plants, while seven out of nine target antibiotics were analyzed in two studied river waters as well as the influent and effluent of wastewater treatment plants at concentrations ranging from <LOQ to 926.32ng/L. Ciprofloxacin predominated in all analyzed influent (552.6–796.2ng/L) and effluent (127–248.7ng/L) samples of WWTP A, whereas cephalosporins including cephalexin (523.3–977.7ng/L) and cefixime (278.65 to 422.1ng/L) were the most abundant detected antibiotics in the influent and effluent of WWTP B. Aqueous phase removal efficiencies were assessed and ranged from 339.83% to 100% for the seven detected antibiotics. “Negative removals” were observed for erythromycin, azithromycin, and cefixime due to the deconjugation of conjugated metabolites via biological transformation in the studied WWTPs. From a statistical point of view, significant differences (p<0.05) were observed in the concentrations of cefixime, cephalexin, azithromycin, and erythromycin in the effluent of both studied WWTPs. Ciprofloxacin and cephalexin were the most abundant detected antibiotics in the two studied river waters. Statistical results revealed that there were significant differences in the concentrations of ciprofloxacin, azithromycin, and erythromycin (p<0.05) in Firozabad ditch (receiving WWTP effluent) and Kan River (non-receiving WWTP effluent) which demonstrated that WWTPs discharges could be an important source of antibiotics being released in water bodies.

A green one-pot synthesis of nitrogen and sulfur co-doped carbon quantum dots for sensitive and selective detection of cephalexin

The article reports a simple, economic, and green method for preparing water-soluble, nitrogen and sulfur co-doped carbon quantum dots via a one-step hydrothermal method. Pomegranate juice served as the carbon source, and the L-cysteine provided nitrogen and sulfur. Co-doped carbon dots were characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy techniques. The co-doped carbon dots served as fluorescent probes for sensitive and selective detection of cephalexin. Briefly, the co-doped carbon dot systems showed quenching of photoluminescence intensity in the presence of cephalexin. The decrease of fluorescence intensity made it possible to analyze cephalexin with satisfactory detection limits and linear ranges. The Sterne–Volmer plot showed a linear relationship (R2 = 0.998) between F0/F and the concentration of cephalexin over the range from 0.3 to 10 μmol L−1. The limit of detection (LOD) was estimated to be 1 × 10−7 mol L−1 (at a signal to noise ratio of 3). To validate the applicability, the described method was successfully applied for the detection of cephalexin in human urine and raw milk samples.

Sonolytic and photocatalytic (sonophotocatalytic) removal of cephalexin from aqueous solution: process optimization using response surface methodology (RSM)

Extensive use of pharmaceutical drugs has resulted in widespread use of antibiotic remedies in the environment and consequently has made a strong public concern worldwide. Present study aimed at assessing the possible effects of combined ultrasound (sonolysis) and UV/ZnO and UV/WO3 photocatalytic processes on the removal of cephalexin from aqueous solutions. A pilot-scale Plexiglas reactor with working volume of 1 L was used in this study. A constant frequency of 40 Hz was used in ultrasound processes. Effects of various experimental parameters on sonophotocatalytic degradation were investigated. These included 200–400 mg/L of ZnO, 100–200 mg/L of WO3, contact time of 60–120 min and cephalexin concentration of 50–100 mg/L. Response surface methodology was applied in the experimental design. Results showed that sonolytic degradation was not significantly effective and the maximum degradation rate reached 19.3. The maximum photocatalytic removal of UV/ZnO and UV/WO3 reached 66.5 and 78.6, respectively. The effect of cephalexin concentration on the efficiency of processes was negative, but contact time and catalytic dosage had direct effects on the process. This was carried out under optimal conditions, including antibiotic concentration of 50 mg/L, contact time of 120 min, 400 mg/L of ZnO and 200 mg/L of WO3. The ratio of BOD5/COD was calculated 0.31 and it ranged from 0 to 0.24 using UV/WO3 and UV/ZnO, respectively. The models of cephalexin removal from photocatalytic processes were quadratic (R2 = 0.966–0.982). Results revealed that successful combination of sonolytic and photocatalytic (sonophotocatalytic) treatments can strongly remove cephalexin from aqueous solutions. © 2017 Desalination Publications. All rights reserved.

Improvement of zeolite adsorption capacity for cephalexin by coating with magnetic Fe3O4 nanoparticles

The removal of cephalexin (CEX) from aqueous solution by natural zeolite (NZ) and magnetic Fe3O4 nanoparticles prepared and coated onto natural zeolite (CZ) was investigated. Magnetic Fe3O4 nanoparticles were synthesized by chemical precipitation of a Fe2+ and Fe3+ salts from aqueous solution by ammonia hydroxide solution. SEM images, XRD patterns, XRF spectroscopy, and FTIR spectroscopy were used to characterize the adsorbents. The maximum CEX removal efficiency was 28% and 93% for NZ and CZ, respectively, at optimized condition (pH7, an amount of adsorbent of 0.6g/L, a concentration of CEX of 40mg/L, contact time of 2h, and a temperature of 20°C). The isotherm adsorption of CEX onto both adsorbents was best fitted with Langmuir isotherm equation and the maximum adsorption capacity was 16.1 and 24.9mg/g for NZ and CZ, respectively. The kinetics followed is second order in nature and the intraparticle diffusion was the dominating mechanism. Thermodynamic parameters (∆G°>0 and ∆H°<0) showed the non-spontaneity and exothermic in nature of adsorption process. However, the results showed that the increasing of nitrate, carbonate, and hardness ions decreased the CEX removal efficiency by different trends but their effect can be ranked as nitrate<carbonate<hardness.

Pharmacokinetics of Immediate and Sustained Release Cephalexin Administered by Different Routes to Llamas (Lama glama).

We investigate the pharmacokinetics of two different cephalexin formulations administered to llamas by the intravenous (IV), intramuscular (IM), and subcutaneous (SC) routes, the minimum inhibitory concentration (MIC) of cephalexin against some Escherichia coli and staphylococci isolated from llamas, and we apply the PK/PD modelling approach, so that effective dosage recommendations for this species could be made. Six llamas received immediate (10 mg/kg, IV, IM, and SC) and sustained (8 mg/kg IM, SC) release cephalexin. Pharmacokinetic parameters were calculated by noncompartmental approach. Immediate release SC administration produced a significantly longer elimination half-life as compared with the IV and IM administration (1.3 ± 0.2 versus 0.6 ± 0.1 and 0.6 ± 0.1 h, resp.) and higher mean absorption time as compared with the IM administration (1.7 ± 0.5 versus 0.6 ± 0.4 h). Absolute bioavailability was in the range of 72–89% for both formulations and routes of administration. Cephalexin MIC90 values against staphylococci and E. coli were 1.0 and 8.0 μg/mL, respectively. Our results show that the immediate release formulation (10 mg/kg) would be effective for treating staphylococcal infections administered every 8 h (IM) or 12 h (SC), whereas the sustained release formulation (8 mg/kg) would require the IM or SC administration every 12 or 24 h, respectively.

Development and Evaluation of Sustained Release Dosage Form using Hydrophilic and Hydrophobic Materials

Cephalexin is a first generation cephalosporin antimicrobial agent with activity against Gram negative microorganisms. Oral therapy with cephalexin results in peak concentration in plasma of 18 mcg/mL after a dose of 500 mg. The usual oral or parenteral antibiotic regimen results in high peak levels that fall well below therapeutic concentration before administration of next dose. For Cephalexin, the plasma concentration above 1.0 mcg/mL is above the MIC in vitro for most of the susceptible microorganisms. These characteristics coupled with the short biological half life of 1 hour suggest that it is a rational candidate for a sustained release dosage form. Based on the pharmacokinetics, the sustained release tablet containing 375 mg Cephalexin monohydrate should release 78.3 mg of cephalexin initially within first 1 h and 46.7 mg of cephalexin per hour for next 5 h of in order to maintain plasma cephalexin concentration of 4.5 mg/L. The sustained release tablets were prepared by wet granulation technique containing HPMC K4M, K15M, K100M, K100LV, ethyl cellulose, Carbopol, Eudragit RS 100, Eudragit RL 100, and Eudragit L100. In vitro release profiles of optimized cephalexin matrix tablets containing HPMC, carbopol and eudragit has shown sustained release up to 6 hours. It was observed that the release rate was slower with higher quantities and higher viscosities of HPMC. The rate of drug release was found in the order HPMC K100LV < K4M < K15M < K100M. The rate of drug release was slower in case of carbopol 974P than carbopol 971P. The drug release from tablets containing eudragit L100 (pH dependent) and eudragits RL100, RS100 (pH independent) was studied. An inverse relation was observed between release of cephalexin and quantity of Eudragit. Eudragit L100 being pH dependent, solubilises at pH above 6. It shows retardant effect in acidic pH for initial two hours and faster release in alkaline pH. Formulations containing HPMC K4, K5, K7and K10, the dominant mechanism for drug release through HPMC based matrix systems may be anomalous (non-fickian) transport. For formulations containing carbopol namely C3 and C7 indicating that drug was released by anomalous transport. On the other hand Eudragit L100 containing formulation (E3) Super case II transport was found to be the release mechanism from matrix system.

Adsorption of cephalexin from aqueous solution using natural zeolite and zeolite coated with manganese oxide nanoparticles

In the present study the adsorption of Cephalexin (CEX) from aqueous solution using natural zeolite (NZ) and zeolite coated with manganese oxide nanoparticles (CZ) were investigated as a function of pH, shaking time, initial CEX concentrations, adsorbent dose, and competitive ions. Scanning electron microscope (SEM) images, X-ray diffraction (XRD) patterns, X-ray fluorescence (XRF) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were used to characterize the adsorbents. The maximum CEX removal efficiency was 28% and 89% for NZ and CZ, respectively, at pH7. The experimental isotherm data were analyzed by Freundlich, Langmuir, Redlich–Peterson, and Sips models. The results showed that Sips isotherm was the best model and the maximum adsorption capacity went from 16.1mg/g for the NZ to 24.5mg/g for the CZ, for 2g/L adsorbent dose. Comparison of these results with those obtained from previous literature suggested that CZ can be potentially used for CEX removal from aqueous solution. The kinetics of CEX adsorption with different initial concentrations were better fit by the pseudo-second-order model, with higher coefficient of determinations and more closely predicted uptake. Finally, the results showed that the intraparticle diffusion was the dominating mechanism.

Dissolution efficiency and bioequivalence study using urine data from healthy volunteers: a comparison between two tablet formulations of cephalexin

&lt;p&gt;The aim of the present study was to assess the bioequivalence of two cephalexin tablet formulations available in the Brazilian market (product A as reference formulation and product B as test formulation). Dissolution efficiency (DE%) was calculated for both formulations to evaluate their &lt;italic&gt;in vitro&lt;/italic&gt;biopharmaceutical features. The oral bioequivalence study was performed in twenty-four healthy volunteers in a crossover design. Single oral dose (tablet containing 500 mg of cephalexin) of each product was administered with two weeks of washout period. Urinary concentrations of cephalexin were measured by high-performance liquid chromatography (HPLC) method and pharmacokinetics parameters were estimated by urinary excretion data. The bioequivalence was determined by the following parameters: the cumulative amount of cephalexin excreted in the urine, the total amount of cephalexin excreted in the urine and the maximum urinary excretion rate of cephalexin. DE values of immediate-release cephalexin tablets (500 mg) were 68.69±4.18% for product A and 71.03±6.63% for product B. Regarding the dissolution test of the two brands (A and B) analysed, both were in compliance with the official pharmacopeial specifications, since the dissolution of both formulations was superior to 80% of the amount declared in the label after 45 minutes of test (A=92.09%±1.84; B=92.84%±1.08). The results obtained indicated that the products A and B are pharmaceutical equivalents. Confidence intervals for the pharmacokinetic parameters were in compliance with the international standards, indicating that products A and B can be considered bioequivalents and, therefore, interchangeable.&lt;/p&gt;

Technological failures caused by cephalexin in set-type sheep’s milk yogurt

Given their broad spectrum, cephalosporins are used for combating mastitis in dairy species. Many cephalosporins, such as cephalexin, have not been authorized for use in lactating sheep and because veterinary drugs for use in small species are lacking, the regulations of several countries allow extra-label use. Incorrect use of extra-label tools may cause residues in milk, and could negatively affect public health by provoking technological failures in the dairy fermenting processes. The effects of cephalexin, at concentrations close to its European Maximal Residue Limit (MRL), have been studied in set-type yogurts made from sheep’s milk. Milk was fortified at different cephalexin concentrations and stored yogurts were evaluated in acidification, textural parameters and microbial evolution terms. The results showed that cephalexin concentrations equal to or below its MRL could mainly inhibit normal Streptococcus thermophilus growth and provoke some alterations to acidity parameters, which were more marked in the L(+)-lactic acid isomer.

Supported liquid membranes with feed dispersion for recovery of Cephalexin

Pertraction through supported liquid membranes with feed dispersion (SLM-FD) has been proposed and studied for simultaneous removal and recovery of Cephalexin from aqueous solutions using a commercially available hollow-fiber module and the carrier Aliquat 336. The feed dispersion, formed by dispersing the feed solution in the organic membrane solution with a mixer, flowed through the shell side of the module, forming the SLM in the nanoporous hollow fibers. Various parameters were investigated including the feed-to-organic volume ratio, initial Cephalexin concentration, Aliquat 336 concentration in the organic membrane solution, KCl concentration in the strip phase, shell side feed-dispersion flow rate, and lumen side strip-solution flow rate. The results showed that an excess of counter ion, KCl, was needed for facilitated transport and that the shell side and lumen side flow rates had little effects on mass transfer performance. The mass transfer process of SLM-FD was elucidated, and a mathematical model was developed to describe the process. Based on this model, both the theoretical and experimental overall mass transfer coefficients were obtained as a function of Aliquat 336 concentration. These mass transfer coefficients were in reasonably good agreement. The average overall mass transfer coefficient obtained was significantly larger than (about 1.7 times) that attained by using the supported liquid membrane with strip dispersion (SLM-SD). In addition, the SLM-FD was shown to be superior to the solvent extraction process in terms of Cephalexin removal from the feed solution.

Supported liquid membranes with organic dispersion for recovery of Cephalexin

Supported liquid membranes with organic dispersion (SLM-OD) have been proposed and investigated for simultaneous removal and recovery of Cephalexin from aqueous solutions by using the carrier Aliquat 336 and a commercially available hollow-fiber module (HFM). The organic dispersion, formed by dispersing a small amount of organic membrane solution in the feed solution with a mixer, flowed through the shell side of the HFM. Investigated various parameters including organic-to-feed volume ratio, Aliquat 336 concentration, initial Cephalexin concentration, KCl concentration, shell-side organic dispersion flow rate, and lumen-side strip solution flow rate. The mass transfer mechanism of the SLM-OD technique was elucidated, and a mathematical model was developed to calculate the overall mass transfer coefficient. The results showed that the overall mass transfer coefficient increased with an increase of organic-to-feed volume ratio or increase of Aliquat 336 concentration, but reduced with the increase of initial Cephalexin concentration. Furthermore, the results indicated that the lumen and shell side flow rates had little effects on mass transfer performance and that an excess amount of KCl was necessary for the facilitated transport. The fractional mass transfer resistances of SLM-OD were calculated based on the resistance-in-series model, showing that the extraction reaction resistance was greatly reduced. In addition, the SLM-OD was shown to be superior to the supported liquid membranes with strip dispersion (SLM-SD) in terms of the improvement of mass transfer performance and the reduced volume requirement of the organic membrane solution.

Removal of Cephalexin Antibiotic and Heavy Metals from Pharmaceutical Effluents using Bacillus subtilis Strain

Removal of Cephalexin Antibiotic and Heavy Metals from Pharmaceutical Effluents using Bacillus subtilis Strain The rapid development of pharmaceutical industries resulted from producing huge amounts of pharmaceutical effluents. These wastes contain several types of toxins including heavy metals and pharmaceutical compounds, which have high toxicity for human and environment. The traditional technologies are not effective to remove both antibiotic compounds and heavy metals. Besides that, these techniques are associated with toxic by-products. Therefore, this study aimed to investigate the potential of Bacillus subtilis strain isolated from sewage effluent for the biodegradation of cephalexin and bioaccumulation of heavy metal ions simultaneously. The efficiency of B. subtilis to remove cephalexin and heavy metals was investigated by the inoculation 6 log10 CFU mL-1 of this strain into sewage effluents containing cephalexin and different concentrations of heavy metals to simulate the pharmaceutical effluents. The results revealed that B. subtilis removed 80% of Ni2+ ions, 85% of Cu2+ and Zn2+ ions, 66% of Pb2+ ions and 88% of Cd2+ ions as well as exhibited the potential to biodegrade of cephalexin by 27, 22 and 21% at 10 mg L-1 of Ni2+, Cu2+ and Zn2+ ions. It can be concluded that B. subtilis strain might be used as an alternative technology for removing heavy metals and antibiotics from pharmaceutical effluents.

Application ofl-cysteine capped core–shell CdTe/ZnS nanoparticles as a fluorescence probe for cephalexin

l-Cysteine capped CdTe/ZnS NPs were prepared in an aqueous system and the fluorescence intensity was significantly reduced when the concentration of cephalexin increased, which proves a good probe for determination of cephalexin in pharmaceutical fields.

Optimization studies for catalytic ozonation of cephalexin antibiotic in a batch reactor

This study examines the effect of pH of solution, cephalexin (CEX) concentration, and O 3 dosage on removal of CEX by catalytic ozonation. All three parameters were found to exert a significant effect on the removal of cephalexin and on the enhancement in biodegradability of solution. The operating conditions were optimized using response surface methodology (RSM) and artificial neural network (ANN). Both RSM and ANN models were found capable of predicting removal of CEX during catalytic ozonation. Simultaneous optimization of two responses (chemical oxygen demand (COD) removal and CEX removal) was carried out using genetic algorithm based multiobjective optimization. Non-dominated Pareto optimal solutions provided the range of optimum conditions for the catalytic ozonation process. The optimized values of pH (9.7), ozone supply (34.5 mg/L), and CEX concentration (33.6 mg/L) using GA multiobjective optimization corresponded to complete conversion of CEX with 72% removal of COD.

Development of cephalexin-loaded poly(ethyl cyanoacrylate) colloidal nanospheres

Abstract This article considers the preparation and physicochemical characterization of a novel colloidal formulation of the β-lactam antibiotic cephalexin, loaded in poly(ethyl cyanoacrylate) colloidal nanospheres. The drug was loaded by means of drug incorporation in the interior of poly(ethyl cyanoacrylate) particles during the polymerization of the respective monomer in aqueous medium. The obtained colloids were characterized by scanning electron microscopy, dynamic and electrophoretic light scattering, Fourier transform infrared and nuclear magnetic resonance spectroscopy. It was found that the drug loading efficiency depends on the initial concentration of monomer and cephalexin in the polymerization medium. The average size of cephalexin-loaded particles was around 400 nm and did not depend significantly on the concentrations of drug and monomer. Drug-loaded particles with drug content as high as 21% (w/w) were prepared. The drug release kinetics was studied in physiological phosphate-buffered saline. It was found that a biexponential model could describe well the experimental release kinetics.