Synthesis of biologically active cefpodoxime and vanillin-based schiff base metal complexes with the detailed biological evaluations.

Schiff bases of existing antimicrobial drugs are an area, which is still to be comprehensively explored to improve drug efficiency against consistently resisting bacterial species. In this study, we have targeted a new and eco-friendly method of condensation reaction that allows the "green synthesis" as well as improved biological efficacy. The transition metal complexes of cefpodoxime with well-enhanced biological activities were synthesized. The condensation reaction product of cefpodoxime and vanillin was further reacted with suitable metal salts of [Mn (II), Cu (II), Fe (II), Zn (II), and Ni (II)] with 1:2 molar ratio (metal: ligand). The characterization of all the products were carried out by using UV-Visible, elemental analyzer, FTIR, 1H-NMR, ICP-OES, and LC-MS. Electronic data obtained by UV-Visible proved the octahedral geometry of metal complexes. The biological activities Schiff base ligand and its transition metal complexes were tested by using in-vitro anti-bacterial analysis against various Gram-negative, as well as Gram-positive bacterial strains. Proteinase and protein denaturation inhibition assays were utilized to evaluate the products in-vitro anti-inflammatory activities. The in vitro antioxidant activity of the ligand and its complexes was evaluated by utilizing the 2,2-diphenyl-1-picrylhydrazyl (DPPH) in-vitro method. The final results proved metal complexes to be more effective against bacterial microorganisms as compared to respective parent drug as well as their free ligands. Patch Dock, a molecular docking tool, was used to dock complexes 1a-5e with the crystal structure of GlcN-6-P synthase (ID: 1MOQ). According to the docking results, complex 2b exhibited a highest score (8,882; ACE = -580.43 kcal/mol) that is well correlated with a high inhibition as compared to other complexes which corresponds to the antibacterial screening outcomes.

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.

In vitro Spectroscopic studies on drug interaction of cefpodoxime proxetil and H2 receptor blockers.

One of the relatively advance 3rd generation cephalosporins, cefpodoxime proxetil, is being used all-around. Generally, these are used for the cure of infections allied to urinary and respiratory tract. These cephalosporins have showed a remarkable in vitro activity against many strains of bacteria which are resistant to other orally used active medicinal substances. It is the first oral 3rd generation cephalosporin to be used in the cure of skin infections. The practice of H2 receptor antagonists, concerning lots of treatments recommended in patients with different types of ulcers and allergic urticarial condition, is raising hazards of unwanted secondary outcomes and drug interactions. Learning of in-vitro interaction between cefpodoxime poxetil and H2 blockers (Ranitidine, Famotidine and Cimetidine) were examined applying UV/Visible spectrophotometry and Infrared spectrometry. In the existence of H2 receptor blockers, the cefpodoxime proxetil availability was found to be decreased in vitro only under specific conditions. Furthermore, complexes of Cefpodoxime proxetil-H2 receptor antagonists were manufactured approving the interaction of these drugs. Finally, the above mentioned spectrophotometric techniques were employed to examine the complexes formed (Cefpodoxime proxetil-cimetidine, cefpodoxime proxetil-famotidine and cefpodoxime proxetil-ranitidine).

Impact of different organic acids on solubility enhancement of cefpodxime proxetil immediate release tablet and its stability studies.

Cefpodoxime proxetil is a third generation cephalosporin antibiotic demonstrates pH dependent solubility and is highly soluble only in acidic pH. The purpose of this investigation was to design and develop immediate release tablets of cefpodoxime proxetil by direct compression method and determine the effect of different solid buffers (organic acids) such as fumaric acid (formulations F1-F4), maleic acid (formulations M1-M4) and citric acid (formulations C1-C4) by using cefpodoxime and acid in the ratios of 4:1, 2:1, 1:1 and 1:2 to achieve pH-independent release of the drug. Physical parameters and assay were found to be within the acceptable range as prescribed in USP 36 / NF 31. In vitro dissolution studies of each formulation were performed in distilled water, USP dissolution medium, HCl buffer solution of pH 1.2, phosphate buffer solutions of pH 4.5 and 6.8 to observe the drug release. The formulations F3, F4, M4 were selected for film coating on the basis of better drug release profile, to protect the drug from chemical degradation through hydrolysis. Film coated formulation F3, F4 and M4 showed a remarkable in vitro release of the drug (72.88±0.43 to 92.67±0.71%) within 30min of observation in all dissolution media and further evaluated by model independent and model dependent approaches. The drug release was found to be best fit to Weibull model as highest r2adjusted (0.924-0.998) and lowest AIC (18.416-54.710) values were obtained in all dissolution media. R Gui® applied for stability studies of F3 and F4 formulations, showing shelf lives of 28 & 27months at ambient and 33 months at accelerated temperatures. Formulation F4 was chosen as best formulation on the basis of physical properties, highest dissolution rate and stability studies.

Susceptibility of cord blood antioxidant enzymes glutathione reductase, glutathione peroxidase and glutathione S-transferase to different antibiotics: in vitro approach.

Cord blood has numerous facilities for life and used in many different areas. Cord blood contains many different catalytic proteins including antioxidant enzymes. Here we purified human cord blood glutathione reductase (hcbGR), glutathione S-transferase (hcbGST) and human cord blood glutathione peroxidase (hcbGPx) from human cord blood erythrocytes and analyzed the inhibition effects of the antibiotics incorporating cefuroxime, ceftriaxone, ceftizoxime and cefoperazone, on these enzymes. K(I) values for the drugs ranged from 10.42 to 28.72 µM for hcbGR, 32.7 to 244.8 µM for hcbGPx, and 32.39 to 267.3 µM for hcbGST. Cefuroxime caused the highest inhibition on all enzymes with KI values of 10.42, 32.39, 32.7 µM for hcbGR, hcbGST, and hcbGPx, respectively. All drugs displayed non-competitive inhibition regardless of their structures. Since these drugs are often used during pregnancy, identification of possible undesired impacts on various parameters has a great importance for pharmacological and medical applications.

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, ß-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.

Technetium-99m-labeled ceftizoxime loaded long-circulating and pH-sensitive liposomes used to identify osteomyelitis.

Osteomyelitis is an infectious disease located in the bone or bone marrow. Long-circulating and pH-sensitive liposomes containing a technetium-99m-labeled antibiotic, ceftizoxime, (SpHL-(99m)Tc-CF) were developed to identify osteomyelitis foci. Biodistribution studies and scintigraphic images of bone infection or non infection-bearing rats that had been treated with these liposomes were performed. A high accumulation in infectious foci and high values in the target-non target ratio could be observed. These results indicate the potential of SpHL-(99m)Tc-CF as a potential agent for the diagnosis of bone infections.

Comparison of cefpodoxime proxetil release and antimicrobial activity from tablet formulations: complexation with hydroxypropyl-ß-cyclodextrin in the presence of water soluble polymer.

This study aims to prove the complexation of cefpodoxime proxetil (CP) by hydroxypropyl-ß-cyclodextrin (HP-ß-CD) in the presence of sodium carboxymethyl cellulose (Na CMC), and makes a comparison of commercial tablets by dissolution and antimicrobial activity studies. The CP--HP-ß-CD complex was prepared by kneading method and characterized by SEM, FTIR and DSC. The solubility method was used to investigate the effect of HP-ß-CD and Na CMC on the solubility of CP. The complex tablets were prepared using direct compression method. Dissolution studies were performed with complex tablets and commercial tablets in pH 1.2, 4.5, 6.8 and 7.4 buffer solutions. It was observed that complexation occurred in all formulations, and HP-ß-CD is able to increase CP solubility and dissolution rate of CP was improved from complex tablets, when compared with commercial tablets. Furthermore, the antimicrobial activity studies revealed that the CP--HP-ß-CD complex and complex tablets were shown to have more effective antimicrobial activity than commercial tablets. It is evident from the results that complexation with HP-ß-CD in the presence of Na CMC is feasible way to prepare a more efficient tablet formulation with improved dissolution and antimicrobial activity.

[Identification of impurity peaks in the HPLC chromatogram by LC-MS and two-dimensional chromatographic correlation spectroscopy].

A novel qualitative analytical method by using two-dimensional chromatographic correlation spectroscopy techniques for recognizing impurity peaks of HPLC methods of quality control and LC-MS chromatographic system was established. The structures of major degradation products of ceftizoxime and cefdinir were identified by LC-MS and MassWorks application; the standard chromatographic and spectral data of the degradation impurities were obtained by high-performance liquid chromatography with diode array detection. The impurity peaks of two-dimensional chromatography were matched by comparison of spectra and calculating correlation coefficients. Peaks in chromatography can be identified accurately and rapidly in different chromatographic systems such as column and mobile phase changed. The method provides a new way and thought to identify the peaks in quality control of impurities without reference impurity substances.

Ceftizoxime loaded ZnO/L-cysteine based an advanced nanocarrier drug for growth inhibition of Salmonella typhimurium.

L-Cysteine coated zinc oxide (ZnO) nano hollow spheres were prepared as a potent drug delivery agent to eradicate Salmonella enterica serovar Typhimurium (S. typhimurium). The ZnO nano hollow spheres were synthesized by following the environmentally-friendly trisodium citrate assisted method and L-cysteine (L-Cys) conjugate with its surface. ZnO/L-Cys@CFX nanocarrier drug has been fabricated by incorporating ceftizoxime with L-Cys coated ZnO nano hollow spheres and characterized using different techniques such as scanning electron microscope (SEM), attenuated total reflection Fourier transform infrared (ATR-FTIR), and X-ray diffraction (XRD) etc. Furthermore, the drug-loading and encapsulation efficiency at different pH levels was measured using UV-vis spectrometer and optimized. A control and gradual manner of pH-sensitive release profile was found after investigating the release profile of CFX from the carrier drug. The antibacterial activity of ZnO/L-Cys@CFX and CFX were evaluated through the agar disc diffusion method and the broth dilution method, which indicate the antibacterial properties of antibiotics enhance after conjugating. Surprisingly, the ZnO/L-Cys@CFX exhibits a minimum inhibitory concentration (MIC) of 5 µg/ml against S. typhimurium is lower than CFX (20 µg/ml) itself. These results indicate the nanocarrier can reduce the amount of CFX dosed to eradicate S. typhimurium.

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.

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.

Computational design of new enzymes for hydrolysis and synthesis of third-generation cephalosporin antibiotics.

Engineering active sites in inert scaffolds to catalyze chemical transformations with unnatural substrates is still a great challenge for enzyme catalysis. In this research, a p-nitrobenzyl esterase from Bacillus subtilis was identified from the structural database, and a double mutant E115A/E188A was designed to afford catalytic activities toward the hydrolysis of ceftizoxime. A quadruple mutant E115A/E188A/L362S/I270A with enhanced catalytic efficiency was created to catalyze the condensation reaction of ethyl-2-methoxy-amino-2-(2-aminothiazole-4-yl) acetate with 7-amino-3-nor-cephalosporanic acid to produce ceftizoxime in a fully aqueous medium. The catalytic efficiencies of the computationally designed mutants E115A/E188A/L362S/I270A and E115A/Y118 K/E188 V/I270A/L362S can be taken as starting points to further improve their properties towards the practical application in designing more ecology-friendly production of third-generation cephalosporins.

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.

Cefpodoxime proxetil.

A comprehensive profile of cefpodoxime proxetil including the nomenclatures, formulae, elemental composition, appearance, uses, and applications. The methods which were developed for the preparation of the drug substance and their respective schemes are outlined. The physical characteristics of the drug including the ionization constant, solubility, X-ray powder diffraction pattern, differential scanning calorimetry, thermal behavior, and spectroscopic studies are included. The methods which were used for the analysis of the drug substance in bulk drug and/or in pharmaceutical formulations includes the compendial, spectrophotometric, electrochemical and the chromatographic methods. The other studies which was carried out on this drug substance are including the drug stability, pharmacokinetics, bioavailability, drug evaluation, comparison and several compiled reviews. Finally, more than two hundred references are listed at the end of this profile.

Isolation and characterization of side-products formed through ∆2-isomerization in the synthesis of cefpodoxime proxetil.

In the synthesis of cephalosporin antibiotics, esterified in 4-position, the ∆2-isomerization is a well-known side reaction proceeding under basic conditions. In this work, we investigated the ∆2-isomerization of the esterified cefpodoxime proxetil. Due to the R-configuration and S-configuration of the stereogenic center in the side chain in 4-position, there are two starting materials being diastereomeric to each other. Furthermore, an additional stereogenic center is formed in the isomerization step, thus leading to four possible products. To the best of our knowledge, in this work for the first time the ∆2-isomerization of the two isolated diastereomers of AMCA proxetil, a precursor of cefpodoxime proxetil, as a starting material is reported. It has been shown, that each diastereomer only reacts to one of the two possible ∆2-diastereomers. The synthesis, isolation and characterization of (R)-diastereomers as well as (S)-diastereomers of ∆2-AMCA proxetil and cefpodoxime proxetil, respectively, are presented.

99m Tc-Ceftizoxime: Synthesis, characterization and its use in diagnosis of diabetic foot osteomyelitis.

INTRODUCTION: The diagnosis of diabetic foot osteomyelitis is crucial and challenging for the proper management of diabetic foot. 99m Tc labelled Ceftizoxime was used as a non-invasive diagnostic agent for diabetic foot osteomyelitis. METHODS: Ceftizoxime [CFT], a third generation cephalosporin, was used in a simple and direct method for the synthesis of 99m TcO4 - labelled infection imaging agent with stannous chloride as reducing agent. Its radiochemical purity was checked by thin Layer chromatography. Partition co-efficient was measured with phosphate buffer and chloroform. The radiochemical complex was injected to control and infected animal model for 3 hours in-vivo localization studied with the help of dual head gamma camera. The labelled complexes were injected to 5 patients of known type II diabetes mellitus suspected of diabetic foot osteomyelitis. All patients underwent dynamic and static 99m Tc-MDP and 99m Tc-CFT scans. RESULTS: The synthesized radio labelled complex was 98.8% pure, with hydrophilic character. When injected to animal model, at 120 minutes, 49.3% was localized in foci of infection with 3.35% in liver and excretion through kidney. Human studies were interpreted as true or false positive and true or false negative based on bone histopathology/culture and clinical follow-up. We found that of 5 patients, 2 were true positive, 2 as true negative with no false positive or negative and 01 patient had soft tissue infection. CONCLUSION: This study showed that 99m Tc-CFT labelled complex could be used for detection of diabetic foot osteomyelitis; however, further confirmation of results with a larger patient population would be optimal.

Preparation & characterization of solid inclusion complex of cefpodoxime proxetil with beta-cyclodextrin.

Cefpodoxime proxetil (CPDX-PR) is an oral cephalosporin antibiotic with poor aqueous solubility and bioavailability. Effect of beta-cyclodextrin on aqueous solubility and dissolution rate of cefpodoxime proxetil was evaluated by the formation of solid inclusion complexes in 1:2 molar ratio of drug: cyclodextrin. Phase solubility study was carried out whereby a typical B's type curve was obtained thus, indicating a 1:2 stoichiometric ratio for optimum complex formation. Solid inclusion complexes in 1:2 molar ratios were prepared by using methods such as physical mixture, solvent evaporation and freeze drying. Prepared complexes were characterized by fourier transform infrared spectroscopy (FT-IR) differential scanning calorimetry (DSC), powder x-ray diffraction (PXRD) and scanning electron microscopy (SEM). Results of in vitro studies appraised of an increased solubility and dissolution rate of cefpodoxime proxetil on complexation with beta- cyclodextrin (P < 0.05) as compared to CPDX-PR alone. Amongst the complexes prepared by different methods, the complex prepared by freeze drying showed the highest dissolution rate (P< 0.01). The in vitro antimicrobial activity of cefpodoxime proxetil and its freeze dried complex (1:2) was studied against both antibiotic-susceptible and antibiotic-resistant clinical isolates of Neisseria gonorrhoeae. The freeze dried complex (1:2) inhibited all penicillin-susceptible strains and penicillinase-producing strains at 0.015 microg/ml concentration. Chromosomally resistant strains which were not responsive to penicillin were inhibited by the complex at 0.125 microg/ml concentration. The study revealed that complexation of cefpodoxime proxetil with beta-cyclodextrin effectively enhanced the aqueous solubility and in vitro antibacterial activity.

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.