Presently, the research using Zebrafish is expanding into areas such as pharmacology, clinical research as a disease model and interestingly in drug discovery. Mammalian models of absorption, distribution, metabolism and excretion (ADME)/pharmacokinetics and efficacy are expensive, laborious and consume large quantities of precious compounds. There is also increasing pressure to limit animal use to situations in which they are absolutely necessary, such as in preclinical toxicity and safety assessment. The use of Zebrafish in pharmaceutical research, drug discovery and development is mainly target screening, target identification, target validation and drug toxicity study. Zebrafish have recently entered the fray as a model animal for some human diseases. It has numerous attributes in toxicology studies and high throughput screening. The fish are more affordable, easier to keep, and faster to rise than mammals, giving a higher-throughput system. Perhaps surprisingly, genes that cause disease in zebrafish are similar to those in humans. Zebrafish being a non-mammalian, drugs can also be tested for toxicity and their potential therapeutic activity against the target more easily than in mammals. The Zebrafish embryo has become an important vertebrate model for assessing drug effects. It exhibits unique characteristics, including ease of maintenance and drug administration, short reproductive cycle and transparency that permits visual assessment of developing cells and organs. Using Zebrafish it is possible to obtain results quickly at lower costs. "Reducing failures early in development is far more important than filling a pipeline with poorly chosen late-stage products likely to fail, and fail expensively."

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In the present study a rapid, specific and economic UV spectrophotometric method has been developed using a solvent composed of methanol : water (80 : 20) to determine the montelukast sodium content in bulk and pharmaceutical dosage formulations. A pre-determined λmax at 344 nm, it was proved linear in the range of 5 to 30 µg/ml, and exhibited good correlation coefficient (R 2 = 0.999). This method was successfully applied to the determination of montelukast sodium content in five marketed brand the results were in good agreement with the label claims. The method was validated statistically and studies for linearity, precision, repeatability and reproducibility. The obtained results proved the method can be employed for the routine analysis of montelukast sodium in bulk as well as in the commercial formulations.

Bioanalysis is an essential part in drug discovery and development. Bioanalysis is related to the analysis of analytes (drugs, metabolites, biomarkers) in biological samples and it involves several steps from sample collection to sample analysis and data reporting. The first step is sample collection from clinical or preclinical studies; then sending the samples to laboratory for analysis. Second step is sample preparation and it is very important step in bioanalysis. In order to reach reliable results, a robust and stable sample preparation method should be applied. The role of sample preparation is to remove interferences from sample matrix and improve analytical system performance. Sample preparation is often labour intensive and time consuming. This guideline defines key elements necessary for the validation of bioanalytical methods. The guideline focuses on the validation of the bioanalytical methods generating quantitative concentration data used for pharmacokinetic and toxicokinetic parameter determinations. Guidance and criteria are given on the application of these validated methods in the routine analysis of study samples from animal and human studies. Measurement of drug concentrations in biological matrices (such as serum, plasma, blood, urine, and saliva) is an important aspect of medicinal product development. It is therefore paramount that the applied bioanalytical methods used are well characterised, fully validated and documented to a satisfactory standard in order to yield reliable results. This review provides an overview of bioanalytical method development and validation and main principles of method validation stages discussed. Keywords: Bioanalysis, Sample Preparation, Bioanalytical Method Development and Validation

Oxygen uptake while breathing cause’s free radical production and in addition to that environmental factors such as pollutants, smoke and certain chemicals also contribute to their formation. Reactive oxygen species is a collective term that includes all reactive forms of oxygen, including both oxygen radicals and several non-radical oxidizing agents that participate in the initiation and/or propagation of chain reaction. Free radicals are atoms, molecules or ions with unpaired electrons that are highly unstable and active towards chemical reactions with other molecules. Antioxidant is any substance that when present at low concentrations compared to those of an oxidizable substrate significantly delays or prevents oxidation of that substrate. Antioxidants block the process of oxidation by neutralizing free radicals. Antioxidant power of proanthocyanidins is 20 times greater than vitamin E and 50 times greater than vitamin C. Proanthocyanidins in Grape seeds have been shown to exhibit strong antioxidant, antimutagenic, anti-inflammatory, anticarcinogenic and antiviral activity. Keywords- Antioxidants, Grape seed, Proanthocyanidins, DPPH activity.

To develop a simple, cheap, accurate, and rapid Reverse Phase High Performance Liquid Chromatographic (RP-HPLC) method and validate as per ICH guidelines for estimation of Didanosine in pharmaceutical dosage forms. The separation was conducted by using mobile phase consisting of methanol: water in the ratio (30:70). The wavelength was found at 246nm. Agilent 1220 Infinity LC with ezchrome software is used for chromatographic determination. The separation was conducted by using Zebra Eclipse XDB-C-18 (4.6×250×5µm) at the flow rate of 1.0 ml/min using variable wavelength detector. The developed method resulted in didanosine eluting at 4.650 min. The method was found to be linear over the concentration range 2-12µg/ml with coefficient regression R2-0.997. Mean recovery was found to be in the range of 99.99%, during accuracy studies. The limit of detection (LOD) and limit of quantitiation (LOQ) was found to be 5 mg/ml and 16 mg/ml respectively. A cheap, accurate, precise, linear and rapid RP-HPLC method was developed and validated for the quantitative estimation of Didanosine as per ICH guidelines. Keywords:-RP-HPLC, Didanosine, Method Validation

Smart polymers are materials that respond to small external stimuli. These are also referred as stimuli responsive materials or intelligent materials. Smart polymers that can exhibit stimuli-sensitive properties are becoming important in many commercial applications. These polymers can change shape, strength and pore size based on external factors such as temperature, pH and stress. The stimuli include salt, UV irradiation, temperature, pH, magnetic or electric field, ionic factors etc. Smart polymers are very promising applicants in drug delivery, tissue engineering, cell culture, gene carriers, textile engineering, oil recovery, radioactive wastage and protein purification. The study is focused on the entire features of smart polymers and their most recent and relevant applications. Water soluble polymers with tunable lower critical solution temperature (LCST) are of increasing interest for biological applications such as cell patterning, smart drug release, DNA sequencing etc.