Kakatiya University

About: Kakatiya University is a education organization based out in Warangal, India. It is known for research contribution in the topics: Aryl & Antibacterial activity. The organization has 2062 authors who have published 2241 publications receiving 27040 citations.

Natural products derived from plants as a source of drugs

Abstract: 10.4103/2231-4040.104709 Nature, the master of craftsman of molecules created almost an inexhaustible array of molecular entities. It stands as an infinite resource for drug development, novel chemotypes and pharmacophores, and scaffolds for amplification into efficacious drugs for a multitude of disease indications and other valuable bioactive agents. Since time immemorial, natural products have been the backbone of traditional system of healing throughout the globe, and have also been an integral part of history and culture. Although the use of bioactive natural products as herbal drug preparations dates back hundreds, even thousands, of years ago, their application as isolated and characterized compounds to modern drug discovery and development started only in the 19th century. It has been well documented that natural products played critical roles in modern drug development, especially for antibacterial and antitumor agents. Even though popularity of the synthetic products increased due to its production cost, time effectiveness, easy quality control, stringent regulation and quick effects, but their safety and efficacy was always remained questionable, resulting in the dependence on the natural products by more than 80% of the total population in the developing world, because of its time tested safety and efficacy. A huge number of natural product-derived compounds in various stages of clinical development highlighted the existing viability and significance of the use of natural products as sources of new drug candidates.

Preparation, characterization and in vitro release kinetics of clozapine solid lipid nanoparticles.

Abstract: Clozapine, a lipophilic antipsychotic drug, has very poor oral bioavailability (<27%) due to first pass effect. Solid lipid nanoparticle (SLN) delivery systems of clozapine have been developed using various triglycerides (trimyristin, tripalmitin and tristearin), soylecithin 95%, poloxamer 188 and charge modifier stearylamine. Hot homogenization of melted lipids and aqueous phase followed by ultrasonication at temperature above the melting point of lipid was used to prepare SLN dispersions. Particle size and zeta potential were measured by photon correlation spectroscopy (PCS) using Malvern Zetasizer. Process and formulation variables have been studied and optimized. Differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) studies were performed to characterize state of drug and lipid modification. In vitro release studies were performed in 0.1 N HCl, double-distilled water and phosphate buffer, pH 7.4, using modified Franz diffusion cell. Stable SLN formulations of clozapine having mean size range of 60-380 nm and zeta potential range of -23 to +33 mV were developed. More than 90% clozapine was entrapped in SLN. DSC and PXRD analysis showed that clozapine is dispersed in SLN in an amorphous state. The release pattern of drug is analyzed and found to follow Weibull and Higuchi equations.

Pharmacokinetics, tissue distribution and bioavailability of clozapine solid lipid nanoparticles after intravenous and intraduodenal administration.

Abstract: Clozapine, a lipophilic effective atypical antipsychotic drug, has very poor oral bioavailability (<27%) due to first pass effect. Clozapine solid lipid nanoparticles have been developed using various triglycerides (trimyristin, tripalmitin and tristearin), soylecithin 95%, poloxamer 188 and stearylamine as a positive charge inducer by hot homogenization followed by ultrasonication method. Particle size and charge measurements were made with Malvern Zetasizer. Pharmacokinetics of clozapine incorporated in solid lipid nanoparticles (SLNs), after intravenous (i.v.) administration to conscious male Wistar rats were studied. The aim of this research was to find out whether the bioavailability of clozapine can be improved by administering clozapine SLN duodenally to rats. Tissue distribution studies of clozapine SLN and suspension were carried out in Swiss albino mice. Average size and zeta potential of SLNs of different lipids with stearylamine ranged from 96.7+/-3.8 to 163.3+/-0.7 nm and 21.3+/-1.3 to 33.2+/-0.6 mV, respectively. AUC((0-infinity)) was increased (up to 2.91-fold) and clearance was decreased (up to 2.93-fold) when clozapine entrapped in SLNs with stearylamine were administered intravenously. Bioavailability of clozapine SLNs were 2.45- to 4.51-fold after intraduodenal administration compared with that of clozapine suspension. In tested organs, the AUC and MRT of clozapine SLNs were higher than those of clozapine suspension especially in brain and reticuloendothelial cell-containing organs. These results indicate that SLN are suitable drug delivery system for the improvement of bioavailability of lipophilic drugs such as clozapine.

A Novel Approach for Motion Artifact Reduction in PPG Signals Based on AS-LMS Adaptive Filter

Abstract: The performance of pulse oximeters is highly influenced by motion artifacts (MAs) in photoplethysmographic (PPG) signals. In this paper, we propose a simple and efficient approach based on adaptive step-size least mean squares (AS-LMS) adaptive filter for reducing MA in corrupted PPG signals. The presented method is an extension to our prior work on efficient use of adaptive filters for reduction of MA in PPG signals. The novelty of the method lies in the fact that a synthetic noise reference signal for an adaptive filtering process, representing MA noise, is generated internally from the MA-corrupted PPG signal itself instead of using any additional hardware such as accelerometer or source-detector pair for acquiring noise reference signal. Thus, the generated noise reference signal is then applied to the AS-LMS adaptive filter for artifact removal. While experimental results proved the efficacy of the proposed scheme, the merit of the method is clearly demonstrated using convergence and correlation analysis, thus making it best suitable for present-day pulse oximeters utilizing PPG sensor head with a single pair of source and detector, which does not have any extra hardware meant for capturing noise reference signal. In addition to arterial oxygen saturation estimation, the artifact reduction method facilitated the waveform contour analysis on artifact-reduced PPG, and the conventional parameters were evaluated for assessing the arterial stiffness.

Synthesis of silver nanoparticles by chemical and biological methods and their antimicrobial properties

Abstract: Biogenic synthesis of nanoparticles offers an attractive alternate to chemical synthesis methods. Various hazard free, eco-friendly methods of synthesis of silver nanoparticles are in operation. In chemical reduction methods, the reducing agent is a chemical solution, whereas in biological ones, the collection of enzymes, especially nitrate reductase, plays this role. The highest antibacterial activity of silver nanoparticles synthesised by chemical and biological methods was found in Staphylococcus aureus and Escherichia coli. The paper aims to discuss some fundamental issues about non-biological methods and benefits about biological methods for silver nanoparticles synthesis and their antibacterial studies.