Browsing by Author "Wijayabandara, J."

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Development of three simple voltammetric techniques for detection of theophylline
(Sri Lanka Association for the Advancement of Science, 2008) Maduwanthi, S.A.N.; Pathiratne, K.A.S.; Wijayabandara, J.
The potential of employing the three voltammetric techniques; linear sweep voltammetry (LSV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV) using pyrolytic graphite working electrode for detection of theophylline (TP), a common drug used for treatment of respiratory diseases was investigated. Phosphate buffer at the concentration of 2.0 x 10-2 mol dm-3 and at the pH of 6.6 were found to be the best electrolytic medium for all three voltammetric techniques. TP was found to undergo an irreversible oxidation reaction producing concentration dependent reproducible anodic peak currents at the peak potentials of +0.995 V, +0.772 V and +0.785 V with respect to Ag(s) / AgCl(s) / Cl-(aq) reference electrode (+0.197 V vs. NHE) for the three techniques, LSV, DPV and SWV, respectively. The optimum scanning rate of working electrode potential for LSV was 100 mV s-1. The optimum scanning rates of working electrode potential and pulse height for DPV were 25 mV s-1 and 140 mV, respectively. The optimum pulse height and frequency for SWV were 110 mV and 50 Hz, respectively. Under optimum conditions, there were good linear relationships between anodic peak current and TP concentration for the three techniques. The linear concentration ranges for LSV, DPV and SWV were from 3.0 x 10 -4 mol dm-3 to 1.3 x 10-3 mol dm-3, 7.0 x 10-5 mol dm-3 to 8.0 x 10-4 mol dm-3 and 5.0 x 10-5 mol dm-3 to 1.1 x 10-3 mol dm-3, respectively. The limit of detection observed with LSV, DPV and SWV were 2.5 x 10-4 mol dm-3, 6.0 x 10 -5 mol dm-3 and 4.0 x 10-5 mol dm-3, respectively. The results obtained during an analysis of a commercial TP drug, theophylline sustained release uncoated tablets with the three techniques, LSV, DPV and SWV were found to exhibit percentage deviations of 4.8 %, 3.1 % and 2.7 %, respectively from the value given on the tablet. All three techniques have potentials for detecting TP in the therapeutic range of 10 to 20 mg dm-3.
Preparation and standardization of Thirasthawalu Churna
(Young Ayurveda Researchers' and Innovators' Symposium (YARIS – 2019), Institutional Research Committee, Gampaha Wickramarachchi Ayurveda Institute, University of Kelaniya, Yakkala, Sri Lanka, 2019) Fernando, K.A.B.; Wijayabandara, J.; Welivitigoda, C.; Jeewanthi, J.A.H.; Kumara, J.M.U.M.; Kumara, M.D.K.A.; Nilanika, C.; Ahila, A.
The world is witnessing an unprecedented growth in the usage of herbal products. Sri Lanka is also a mother hub for natural herbs based science. Herbal drug technology is used for converting botanical into medicines, and for standardization and quality control with proper integration of modern scientific techniques and traditional knowledge. WHO Specific guidelines are used for the assessment of the safety, efficacy, quality and purity throughout all phases of its cycle for global harmonization. An overview was done covering the different techniques involved in standardization of crude or finished compound drugs so far as macroscopic, microscopic, physical, chemical and biological methods. Standardization of the individual ingredients help to be responsible for the desired pharmacological effect. The study initiated with the preparation and standardization of the Thirasthawalu Churna. Thirasthawalu Churna was mentioned in Ola leaves manuscript No - 564. The herbal preparation consists of Perumkayam, Vadakaha, Rathnetul, Viyali Inguru, Asamodagam, Aralu, Suwadakottan and Thirasthavalu as ingredients and recommended in the treatment of Kusapilika (Abdominal cancer). The organoleptic characters such as color, taste, odor, smell and consistency for Aralu and Thirasthawalu were evaluated. Physicochemical parameters were determined as per WHO guidelines and reported as total ash, acid insoluble ash, moisture, pH, water soluble extractive, ethanol soluble extractive and Thin Layer Chromatography (TLC) developed for different solvent systems. Detection of TLC finger print profiles were carried under UV light at the wavelength of 254nm and 366nm and also color of the spots were recorded after derivate with Ethanol sulphuric acid regent. The procedures developed in the present study will serve as a protocol for the herbal preparation which minimizes batch to batch variation with assure safety, efficacy, quality and acceptability as an herbal that is used in Kusa pilika and Grahani. Further studies are needed to ensure standardization of other ingredients