Pharmacological assessment of Co3O4, CuO, NiO and ZnO nanoparticles via antibacterial, anti-biofilm and anti-quorum sensing activities.

Infectious diseases have risen dramatically as a result of the resistance of many common antibiotics. Nanotechnology provides a new avenue of investigation for the development of antimicrobial agents that effectively combat infection. The combined effects of metal-based nanoparticles (NPs) are known to have intense antibacterial activities. However, a comprehensive analysis of some NPs regarding these activities is still unavailable. This study uses the aqueous chemical growth method to synthesize Co3O4, CuO, NiO and ZnO NPs. The prepared materials were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. The antibacterial activities of NPs were tested against Gram-positive and Gram-negative bacteria using the microdilution method, such as the minimum inhibitory concentration (MIC) method. The best MIC value among all the metal oxide NPs was 0.63 against Staphylococcus epidermidis ATCC12228 through ZnO NPs. The other metal oxide NPs also showed satisfactory MIC values against different test bacteria. In addition, the biofilm inhibition and antiquorum sensing activities of NPs were also examined. The present study presents a novel approach for the relative analysis of metal-based NPs in antimicrobial studies, demonstrating their potential for bacteria removal from water and wastewater.

Physical properties and pharmacological applications of Co3O4, CuO, NiO and ZnO nanoparticles.

Nano materials have found developing interest in biogenic approaches in the present times. In this study, metal oxide nanoparticles (NPs) such as cobalt oxide (Co3O4), copper oxide (CuO), nickel oxide (NiO) and zinc oxide (ZnO), were synthesized using a convenient and rapid method. The structural features of synthesized metal oxide NPs were studied using various microscopic and spectroscopic techniques like SEM, TEM, XRD, FTIR and EDX. The characterization results confirmed that the prepared NPs possess highly pure, unique and crystalline geometry with size ranging between 10 and 20 nm. The synthesized nanoparticles were successfully employed for pharmacological applications. Enzyme inhibition potential of NPs was evaluated against the urease and tyrosinase enzymes. The percent inhibition for the urease enzyme was observed as 80 to 90% by using Co3O4, CuO, NiO and ZnO NPs while ZnO NPs were found to have best anti-urease and anti-tyrosinase activities. Moreover, effective inhibition was observed in the case of ZnO NPs at IC50 values of 0.0833 and 0.1732 for urease and tyrosinase enzymes which were comparable to reference drugs thiourea and kojic acid. The lower the IC50 value, higher the free radical scavenging power. Antioxidant activity by DPPH free radical scavenging method was found moderately high for the synthesized metal oxide NPs while best results were obtained for Co3O4 and ZnO NPs as compared to the standard ascorbic acid. Antimicrobial potential was also evaluated via the disc diffusion and well diffusion methods. CuO NPs show a better zone of inhibition at 20 and 27 mm by using both methods. This study proves that the novel metal oxide NPs can compete with the standard materials used in the pharmacological studies nowadays.

Design and in vitro/in vivo Evaluation of Polyelectrolyte Complex Nanoparticles Filled in Enteric-Coated Capsules for Oral Delivery of Insulin.

Insulin is one of the most important drugs in the treatment of diabetes. There is an increasing interest in the oral administration of insulin as it mimics the physiological pathway and potentially reduces the side effects associated with subcutaneous injection. Therefore, insulin-loaded polyelectrolyte complex (PEC) nanoparticles were prepared by the ionic cross-linking method using protamine sulfate as the polycationic and sodium alginate as the anionic polymer. Taguchi experimental design was used for the optimization of nanoparticles by varying the concentration of sodium alginate, the mass ratio of sodium alginate to protamine, and the amount of insulin. The optimized nanoparticle formulation was used for further in vitro characterization. Then, insulin-loaded PEC nanoparticles were placed in hard gelatin capsules and the capsules were enteric-coated by Eudragit L100-55 (PEC-eCAPs). Hypoglycemic effects PEC-eCAPs were determined in vivo by oral administration to diabetic rats. Furthermore, in vivo distribution of PEC nanoparticles was evaluated by fluorescein isothiocyanate (FITC) labelled nanoparticles. The experimental design led to nanoparticles with a size of 194.4 nm and a polydispersity index (PDI) of 0.31. The encapsulation efficiency (EE) was calculated as 95.96%. In vivo studies showed that PEC-eCAPs significantly reduced the blood glucose level of rats at the 8th hour compared to oral insulin solution. It was concluded that PEC nanoparticles loaded into enteric-coated hard gelatin capsules provide a promising delivery system for the oral administration of insulin.

Simultaneous Determination of Amlodipine and Irbesartan in their Pharmaceutical Formulations by Square-Wave Voltammetry.

BACKGROUND: Hypertension is one of the most important health problems in the world and irbesartan and amlodipine are used in combination in various dosages for the treatment of high blood pressure. OBJECTIVE: The aim of this study is to develop a fast, easy, sensitive, accurate, and precise squarewave voltammetry method for simultaneous determination of irbesartan and amlodipine besylate from pharmaceutical formulations at a hanging mercury drop electrode. METHODS: In the applied method, since both active substances gave a peak at different potentials, no interference occurred between them. In optimization studies, Britton-Robinson buffer of pH 8.0 was chosen, in which the most appropriate peak shape and maximum peak current were observed. At the same time, as a result of instrumental parameter optimization to obtain reproducible results, 6 mV for scan increment, 30 mV for pulse amplitude, and 50 Hz for frequency were found suitable. RESULTS: As a result of the calibration studies of the optimized method, linear working ranges were determined as 1.00-13.08 µg mL-1 for irbesartan and 5.83-16.51 µg mL-1 for amlodipine besylate. Limit of detection and limit of quantitation values were respectively calculated as 0.63 and 1.00 µg mL-1 for irbesartan and 0.50 and 1.98 µg mL-1 for amlodipine besylate. The results of precision values (RSD) ranged from 0.67% to 2.31% for irbesartan and 0.65% to 1.49% for amlodipine besylate. Accuracy values were calculated as -0.15% to 1.63% for irbesartan and -0.07% to 3.78% for amlodipine besylate. The results obtained from the recovery studies ranged from 101.05% to 102.78% and from 98.88% to 102.20% for amlodipine besylate and irbesartan, respectively. CONCLUSION: After the validation studies of the developed method were carried out, it was successfully applied to pharmaceutical formulations containing these active substances.

Molecular Identification and Antimicrobial Activity of Vaginal Lactobacillus sp.

BACKGROUND: The genus Lactobacillus has recently been the focal point of researchers due to their ability to produce secondary metabolites with antimicrobial effects. OBJECTIVE: The aim of this study was to identify vaginal Lactobacillus sp. by analyzing 16S rRNA gene sequence, to investigate into antimicrobial activities of secondary metabolites produced by these isolates and to determine the quantities of lactic acid, acetic acid and hydrogen peroxide in secondary metabolites using High-Performance Liquid Chromatography. METHODS: Antimicrobial activities of secondary metabolites were investigated against test microorganisms using Agar Well Diffusion and Agar Spot Methods. RESULTS: According to the results, 18 L. crispatus, 17 L. gasseri, 5 L. jensenii, 4 L. vaginalis, 3 L. fermentum, 2 L. coleohominis, 1 L. saerimneri, 1 L. reuteri, 1 L. johnsonii and 1 L. helveticus were identified. Isolates were frequently found to be effective against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae RSKK 578 and Bacillus subtilis ATCC 6633. None of the isolates showed activity against Staphylococcus aureus ATCC 43300, S. epidermidis ATCC 12228, S. epidermidis ATCC 35984 and Candida albicans ATCC 10231. Secondary metabolites of all tested isolates contain hydrogen peroxide between 7.306 and 0.33 µg/µL range. CONCLUSION: It was found that the secondary metabolites of some isolates contained both acetic and lactic acid, while some of them contained either acetic or lactic acid.

Bioanalytical LC/MS study of potential bacterial transglycosylation inhibitors.

Bacterial transglycosylation is an interesting target in antibiotic drug development. An in vitro transglycosylation assay was developed and used to search for possible inhibitors of Staphylococcus aureus Penicillin Binding Protein 2-mediated transglycosylation. Since the substrate, Lipid II, has no UV-chromophore, the assay relies on LC coupled to MS for analysis of the incubation mixtures. Extracts from Thymus sipyleus, Salvia verticillata, Salvia virgata and Oolong tea were tested, as well as epigallocatechin gallate and ursolic acid, which are chemical compounds derived from plants. Matrix effects hampered Lipid II quantification in samples treated with very high concentrations of extracts. None of these extracts or isolated compounds appeared to have inhibitory activities towards the transglycosylation function of Penicillin Binding Protein 2.

Multivariate optimization of separation conditions for simultaneous determination of acemetacin and chlorzoxazone in a pharmaceutical preparation by HPLC using response surface methodology.

A new, fast, accurate, precise, and sensitive RP-HPLC method for the simultaneous determination of acemetacin and chlorzoxazone has been developed. Response surface methodology with a central composite design was used to optimize the acetonitrile and ammonium acetate percentage in the mobile phase and pH of ammonium acetate. The optimum separation was achieved on a C18 column (250 x 4.6 mm id, 5 microm particle size) using the mobile phase methanol-acetonitrile-0.02 M ammonium acetate, pH 9.4 (25 + 35 + 40, v/v/v) at a flow rate of 1.5 mL/min; UV detection at 270 nm, and cyanocobalamin as an internal standard. This developed method was validated and successfully applied to a coated tablet pharmaceutical preparation.

Liquid chromatographic and spectrophotometric determination of diflucortolone valerate and isoconazole nitrate in creams.

A new RP-LC method and two new spectrophotometric methods, principal component regression (PCR) and first derivative spectrophotometry, are proposed for simultaneous determination of diflucortolone valerate (DIF) and isoconazole nitrate (ISO) in cream formulations. An isocratic system consisting of an ACE C18 column and a mobile phase composed of methanol-water (95 + 5, v/v) was used for the optimal chromatographic separation. In PCR, the concentration data matrix was prepared by using synthetic mixtures containing these drugs in methanol-water (3 + 1, v/v). The absorbance data matrix corresponding to the concentration data matrix was obtained by measuring the absorbances at 29 wavelengths in the range of 242-298 nm for DIF and ISO in the zero-order spectra of their combinations. In first derivative spectrophotometry, dA/dlambda values were measured at 247.8 nm for DIF and at 240.2 nm for ISO in first derivative spectra of the solution of DIF and ISO in methanol-water (3 + 1, v/v). The linear ranges were 4.00-48.0 microg/mL for DIF and 50.0-400 microg/mL for ISO in the LC method, and 2.40-40.0 microg/mL for DIF and 60.0-260 microg/mL for ISO in the PCR and first derivative spectrophotometric methods. These methods were validated by analyzing synthetic mixtures. These three methods were successfully applied to two pharmaceutical cream preparations.

Development and validation of spectrophotometric and high-performance column liquid chromatographic methods for the simultaneous determination of dienogest and estradiol valerate in pharmaceutical preparations.

Simultaneous determination of dienogest (DIE) and estradiol valerate (EST) in sugar-coated tablets was performed by using HPLC and spectrophotometry. In HPLC, the separation was achieved on an ACE C8 column using the mobile phase acetonitrile-NH4NO3 (0.03 M, pH 5.4; 70 + 30, v/v) at a flow rate of 2 mL/min. The detection wavelength was 280 nm, and cyproterone acetate was selected as an internal standard. The linearity range was 3.0-45.0 microg/mL for DIE and 18.0-100.0 microg/mL for EST. As spectrophotometric methods, two chemometric methods, principal component regression and partial least-squares, were developed. In the chemometric techniques, the concentration data matrix was prepared by using mixtures containing these drugs in methanol-water (3 + 1, v/v). The absorbance data matrix corresponding to the concentration data matrix in these methods was obtained by the measurement of absorbances in their zero-order spectra; then, the calibration was obtained by using the data matrix for the prediction of unknown concentrations of DIE and EST in their binary mixture. Working ranges were found as 2.0-24.0 microg/mL for DIE and 20.0-270.0 microg/mL EST in the methods. These three developed methods were validated and successfully applied to a pharmaceutical preparation, a sugar-coated tablet, and the results were compared with each other.