Validation and development of RP-HPLC method for quantification of glibenclamide in rat plasma and its application to pharmacokinetic studies in wistar rats.

Herein, we report a novel, simple, specific, accurate and cost-friendly validated reverse phase-high performance liquid chromatographic (RP-HPLC) method for the quantification of second generation sulphonylurea based antidiabetic drug, glibenclamide (GLB) in rat plasma and its application to calculate pharmacokinetic parameters in wistar rats. The internal standard used was flufenamic acid. The chromatographic separation was conducted on C18 column (250 mm × 4.6 mm x 5 µm, Agilent-Zorbax, SB) using isocratic elution with mobile phase containing Acetonitrile: Water (1:1; v/v) pH adjusted to 4.0 with 0.03 % glacial acetic acid and detected by photo-diode array as detector. Calibration curves made in the rat plasma were linear in the range of 50-1200 ng/ml with r2 = 0.998. The LLOQ was 40 ng/ml. This method was effectively applied for pharmacokinetic studies of Glibenclamide following administration through oral route as solid dispersion formulation to Wistar rats. Several methods are available in the literature which can be employed for the quantification of Glibenclamide but such methods are tedious, provide lower sensitivity, less simultaneous resolution and are time-consuming. Therefore the present methods suits best for the quantification of Glibenclamide from Wistar rats.

Simultaneous quantification of losartan potassium and its active metabolite, EXP3174, in rabbit plasma by validated HPLC-PDA.

Herein, we report a novel, accurate and cost-effective validated analytical method for the quantification of losartan potassium and its active metabolite, EXP 3174, in rabbit plasma by reversed-phase high-performance liquid chromatography. Valsartan was used as an internal standard. The method was validated as per International Conference on Harmonization guidelines. The analytes were extracted in rabbit plasma using liquid-liquid extraction technique and analyzed at 247 nm after separation through a reverse-phase C18 column. The isocratic mobile phase used is a mixture of acetonitrile, water and glacial acetic acid in the ratio of 60:40:1 v/v/v maintained at pH 3.4. All calibration curves showed a good linear relationship (r > 0.995) within the test range. Precision was evaluated by intra- and interday tests with RSDs <1.91% and accuracy showed validated recoveries of 86.20-101.11%. Based on our results, the developed method features good quantification parameters and can serve as an effective quality control method for the standardization of drugs.

Recent trends using natural polymeric nanofibers as supports for enzyme immobilization and catalysis.

All the disciplines of science, especially biotechnology, have given continuous attention to the area of enzyme immobilization. However, the structural support made by material science intervention determines the performance of immobilized enzymes. Studies have proven that nanostructured supports can maintain better catalytic performance and improve immobilization efficiency. The recent trends in the application of nanofibers using natural polymers for enzyme immobilization have been addressed in this review article. A comprehensive survey about the immobilization strategies and their characteristics are highlighted. The natural polymers, e.g., chitin, chitosan, silk fibroin, gelatin, cellulose, and their blends with other synthetic polymers capable of immobilizing enzymes in their 1D nanofibrous form, are discussed. The multiple applications of enzymes immobilized on nanofibers in biocatalysis, biosensors, biofuels, antifouling, regenerative medicine, biomolecule degradation, etc.; some of these are discussed in this review article.

Green Synthesis, Spectroscopic Characterization and Biomedical Applications of Carbon Nanotubes.

Carbon nanotubes are nano-sized cylindrical chicken wire-like structures made of carbon atoms. Carbon nanotubes have applications in electronics, energy storage, electromagnetic devices, environmental remediation and medicine as well. The biomedical applications of carbon nanotubes can be owed to features like low toxicity, non-immunogenicity, high in vivo stability and rapid cell entry. Carbon nanotubes have a great prospect in the treatment of diseases through diagnostic as well as therapeutic approaches. These nanostructures are interesting carriers for delivery and translocation of therapeutic molecules e.g. proteins, peptides, nucleic acids, drugs, etc. to various organs like the brain, lungs, liver, and pancreas. Commonly used methods to synthesize carbon nanotubes are arc discharge, chemical vapor deposition, pyrolysis, laser ablation etc. These methods have many disadvantages such as operation at high temperature, use of chemical catalysts, prolonged synthesis time and inclusion of toxic metallic particles in the final product requiring additional purification processes. In order to avoid these setbacks, various green chemistry-based synthetic methods have been devised, e.g., those involving interfacial polymerization, supercritical carbon dioxide drying, plant extract assisted synthesis, water- assisted synthesis, etc. This review will provide a thorough outlook of the eco-friendly synthesis of carbon nanotubes reported in the literature and their biomedical applications. Besides, the most commonly used spectroscopic techniques used for the characterization of carbon nanotubes are also discussed.