Synthesis, characterization and assessment of antioxidant and antibacterial potential of dihydroquinoline-3-carboxylic acid and their metal derivatives.

Metal complexes of drug are used to inhibit growth of pathogenic microorganisms and reduces drug resistance. Moxifloxacin is a dihydroquinoline-3-carboxylic acid 4th generation fluoroquinolone antibiotic that has tendency to bind with metal ions. In current study four moxifloxacin-metal complexes i.e. Moxifloxacin-sliver (Moxi-Ag), Moxifloxacin-rhodium (Moxi-Rh), Moxifloxacin-titanium (Moxi-Ti) and Moxifloxacin-rubidium (Moxi-Rb) have been synthesized and evaluated for antibacterial activities against resistant microorganisms along with antioxidant effects. The structure elucidation was carried out using FTIR, 1H- NMR and UV-Vis spectroscopy. Agar well diffusion method and DPPH (1, 1- dipheny1-2-picrylhydrazyl) methods were used to study the antibacterial and antioxidant activity respectively. Both 1H NMR and FTIR spectra clearly showed that Moxi-metal complexes are formed due to change in their carboxyl stretching band in IR, H-2 and H-5 peak position in 1H NMR. All the Moxi-metal complexes showed distinguished antibacterial effects against both Gram-negative and Gram-positive bacteria as compared to drug which was found resistant against many microorganisms. Moxi-Rb and Moxi-Ag metal complexes showed higher antioxidant activity (IC50 values range from 8.26 - 9.19 µg/ml) than Moxi-Ti and Moxi-Rh metal complexes (IC50 range from 11.23 - 14.65 µg/ml).

Semicarbazones, thiosemicarbazone, thiazole and oxazole analogues as monoamine oxidase inhibitors: Synthesis, characterization, biological evaluation, molecular docking, and kinetic studies.

A series of semicarbazone, thiosemicarbazone, thiazole, and oxazole derivatives were designed, synthesized, and examined for monoamine oxidase inhibition using two isoforms, i.e., MAO-A and MAO-B. Among all the analogues, 3c and 3j possessed substantial activity against MAO-A with IC50 values of 5.619 ± 1.04 µM and 0.5781 ± 0.1674 µM, respectively. Whereas 3d and 3j were active against monoamine oxidase B with the IC50 values of 9.952 ± 1.831 µM and 3.5 ± 0.7 µM, respectively. Other derivatives active against MAO-B were 3c and 3g with the IC50 values of 17.67 ± 5.6 µM and 37.18 ± 2.485 µM. Moreover, molecular docking studies were achieved for the most potent compound (3j) contrary to human MAO-A and MAO-B. Kinetic studies were also performed for the most potent analogue to evaluate its mode of interaction with MAO-A and MAO-B.

Scanning electron microscopy (SEM) and atomic absorption spectroscopic evaluation of Raphanus sativus L. seeds grown in Pakistan.

Raphanus sativus L. (Brassicacae) possesses numerous health benefits due to presence of a host of secondary metabolites in its various parts. The present study investigated the nutritive value of Raphanus sativus (RS) seeds and seed oil. Proximate and physico chemical analysis were carried out by official AOAC (Association of Official Analytical Chemists) and AOCS (American oil chemist society) methods. Scanning electron microscopy (SEM) together with energy dispersive X-ray spectroscopy (EDS) described the surface morphology along with atomic elemental composition of the sample. Mineral contents were evaluated by Atomic absorption spectroscopy. Moisture content was 8.67±0.08% whereas protein, crude fiber, crude fat, carbohydrates, total ash values were reported as 20.13±0.15%, 7.86±0.15%, 32.27±0.25%, 27.32±0.85%, 3.75±0.02% respectively. EDS determined carbon, oxygen, magnesium, sulfur and potassium in seeds. All physico-chemical properties varied insignificantly for the two extraction methods, except for acid value and unsaponifiable matter, which were higher for Soxhlet's extracted oil than cold pressed oil. The mineral composition revealed potassium in the highest concentrations in seeds and seed oil i.e.1660.65±69.26 ppm and 47.80 ± 7.02 ppm respectively. The study suggested that the seed and seed oil could be a potential source of naturally originated raw material for the nutritive and pharmaceutical aid.

Determining the release kinetics of risperidone controlled release matrices to treat schizophrenia.

Risperidone is an atypical antipsychotic agent clinically used to treat schizophrenia, bipolar diseases, and autism. Usually, the frequency of doses is twice daily. In the present study, risperidone controlled release matrices formulated using hydrophilic and hydrophobic polymers. The tablets were prepared by direct compression. The pre-compression and post-compression properties were assessed, along with swelling studies. The morphology of particles observed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The stability study on the drug was performed using thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The optimized formulation was prepared with the help of hydrophilic polymer K100M (40% ratio). Furthermore, release kinetics had investigated. The release pattern of optimized formulation FT5 fitted best to zero-order kinetics and showed excellent release characteristics. The model-independent approach had been used, formulations FT6 and FT8 showed resemblance with FT5 in all three media, respectively. The once daily formulation of risperidone could be beneficial for schizophrenia patients and their caregivers and will improve patient compliance.

Immunomodulatory activity and chemical characterization of fixed oils obtained from different parts of Oxytropis glabra DC.

Oxytropis glabra DC. is a plant with enormous therapeutic vitality. In the present study a comparison of lipophilic profiling of different parts of O. glabra has been carried out by using gas chromatography-mass spectrometry. A total of 32 compounds have been identified from this plant, amongst which 31 have been identified for the first time. These compounds have been further confirmed from their Van den Dool and Kratz (I) Indices. Out of these 32 compounds, 18 have been identified from flower (80.94%), 15 from fruit (85.36%), 11 from leaves (66.35%) and 11 from root (45.96%). The major class of metabolite identified from different parts is fatty acid. Hydrocarbons have also been detected in flower and fruit but not in root and leaves. The extracts were screened for their immunomodulatory activity on whole blood cells. The root oil was found to be moderately active (IC50 32.3 µg/mL). At present only limited data is available on the phytochemical composition of O. glabra.

Pharmacokinetic and bioequivalence studies of immediate release diclofenac potassium tablets (50mg) in healthy volunteers.

This study was conducted with the aim to determine the pharmacokinetic and bioequivalence of diclofenac potassium 50 mg test (F4) tablet formulation with reference product (Caflam). Present study was single dose, randomized, two phase cross over design, conducted in 12 healthy Pakistani volunteers and planned in accordance with FDA guidelines. In this study a simple, selective, sensitive and reproducible HPLC procedure was developed and validated for the estimation of diclofenac potassium in plasma. The process was validated in the range of 50 - 0.05 µg.mL-1 and used in bioequivalence trial of two products. Multiple blood samples were collected at various time points (0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12 and 14 hr after treating volunteers with test (F4) and marketed reference brand. Plasma separation and deproteination were carried out with acetonitrile; samples (20µL) were injected using the validated HPLC method. Various pharmacokinetic parameters (compartmental and noncompartmental) were estimated using KineticaTM 4.4.1 (Thermo Electron Corp. USA). Bioequivalence among the products was established by calculating the 90% CI with log and non log transformed data for Cmaxcalc, Tmaxcalc, AUC0-∞, AUCtot and AUClast using two way ANOVA and Schirmann's Two one sided t- test. No significant difference was found between log and non-log data. The 90% confidence interval values using log transformed data for AUC0-∞ (0.997-1.024), AUCtot (1.004-1.031), AUClast (0.997 -1.024), Cmaxcalc (0.994-1.007) and Tmaxcalc (0.996-1.013) for the trial and reference products were found within the FDA acceptable limits of 0.8-1.25. Results were further verified by the Schirmann's one-sided t test. Results showed the bioequivalence of test and reference formulations. Both the products were well tolerated.

Decitabine nanoconjugate sensitizes human glioblastoma cells to temozolomide.

In this study, we developed and characterized a delivery system for the epigenetic demethylating drug, decitabine, to sensitize temozolomide-resistant human glioblastoma multiforme (GBM) cells to alkylating chemotherapy. A poly(lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) based nanoconjugate was fabricated to encapsulate decitabine and achieved a better therapeutic response in GBM cells than that with the free drug. After synthesis, the highly efficient uptake process and intracellular dynamics of this nanoconjugate were monitored by single-molecule fluorescence tools. Our experiments demonstrated that, under an acidic pH due to active glycolysis in cancer cells, the PLGA-PEG nanovector could release the conjugated decitabine at a faster rate, after which the hydrolyzed lactic acid and glycolic acid would further acidify the intracellular microenvironment, thus providing positive feedback to increase the effective drug concentration and realize growth inhibition. In temozolomide-resistant GBM cells, decitabine can potentiate the cytotoxic DNA alkylation by counteracting cytosine methylation and reactivating tumor suppressor genes, such as p53 and p21. Owing to the excellent internalization and endolysosomal escape enabled by the PLGA-PEG backbone, the encapsulated decitabine exhibited a better anti-GBM potential than that of free drug molecules. Hence, the synthesized nanoconjugate and temozolomide could act in synergy to deliver a more potent and long-term antiproliferative effect against malignant GBM cells.

PLGA-PEG nano-delivery system for epigenetic therapy.

Efficient delivery of cytidine analogues such as Azacitidine (AZA) into solid tumors constitutes a primary challenge in epigenetic therapies. We developed a di-block nano-vector based on poly(lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) for stabilization of the conjugated AZA under physiological conditions. With equimolar drug content, our nano-conjugate could elicit a better anti-proliferative effect over free drug in breast cancer both in vitro and in vivo, through reactivation of p21 and BRCA1 to restrict cell proliferation. In addition, we applied single-molecule fluorescence tools to characterize the intracellular behavior of the AZA-PLGE-PEG nano-micelles at a finer spatiotemporal resolution. Our results suggest that the nano-micelles could effectively enrich in cancer cells and may not be limited by nucleoside transporters. Afterwards, the internalized nano-micelles exhibit pH-dependent release and resistance to active efflux. Altogether, our work describes a delivery strategy for DNA demethylating agents with nanoscale tunability, providing a cost-effective option for pharmaceutics.

Development and validation of an HPLC-UV method for the determination of gatifloxacin in bulk material, pharmaceutical formulations, human plasma and metal complexes.

A simple reversed phase HPLC method was developed for the quantitative determination of gatifloxacin (GTX) in the bulk material, pharmaceutical formulations and human serum using Mediterranea C18 (25 x 0.46 mm, 5 mm) column. The mobile phase, acetonitrile, methanol and water (40:40:20 v/v pH 2.7 adjusted by phosphoric acid), was delivered at a flow rate of 1.0 ml/min. The eluent was monitored using spectrophotometric detection at 286 nm. The method is specific to GTX and able to resolve the drug peak from formulation excipients and metal impurities. The method is accurate (99.18-101.87%), precise (intra-day variation 0.14-1.67% and inter-day variation 0.32-1.80%) and linear within the range 0.1-25 microg/ml (R2=0.999) concentration and was successfully used in monitoring left over drug in drug-metal complexes. The detection limit of GTX at a signal-to-noise ratio of 3 was 1.73 ng/ml in human plasma while quantification limit in human serum was 5.77 ng/ml. The proposed method is applicable to routine analysis of GTX in pharmaceutical formulations as well as in human plasma samples.

Identification of anti-inflammatory and other biological activities of 3-carboxamide, 3-carbohydrazide and ester derivatives of gatifloxacin.

BACKGROUND: Seventeen 1,4-dihydroquinoline-3-carboxamide and 1,4-dihydroquinoline-3-carbohydrazide derivatives of gatifloxacin have been prepared with a facile one step synthesis aiming to improve antibacterial, antifungal and immunological activities. The methodology allows the introduction of a variety of substituents such as amines, alcohol, phenol, amides and alkyl halides into the core structure of gatifloxacin. RESULTS: The analog N-(3-aminophenyl)-1-cyclopropyl-6-fluoro-8-methoxy-7-(3-methylpiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxamide has been identified as a potentially excellent anti-inflammatory agent, which exhibited highly potent effects on the oxidative burst activity of whole blood phagocytes (IC50 <12.5 µg mL-1), neutrophils (IC50 <0.1 µg mL-1) and macrophages phagocytes (IC50 <3.1 µg mL-1) as well as potent T-cell proliferation inhibitory effect (IC50 3.7 µg mL-1) while having comparable antibacterial activity to gatifloxacin. Another analog, 1-cyclopropyl-6-fluoro-8-methoxy-7-(3-methylpiperazin-1-yl)-4-oxo-N-phenyl-1,4-dihydroquinoline-3-carbohydrazide has tremendous T-cell proliferation inhibitory effect IC50 <3.1 µg mL-1 as compared to prednisolone, whereas, 3,5-dihydroxyphenyl1-cyclopropyl-6-fluoro-8-methoxy-7-(3-methylpiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylate and 2-hydroxyphenyl-1-cyclopropyl-6-fluoro-8-methoxy-7-(3-methylpiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylate envision good inhibitory activity on T-cells proliferation (IC50 6.8 & 8.8 µg mL-1 respectively). CONCLUSIONS: The structural modification at carboxylic group has resulted in improved anti-inflammatory activities with comparable antibacterial activity to gatifloxacin. We believe that C3 structural modifications of gatifloxacin are definitely important in bringing major immunomodulatory changes in these compounds.