Dzulkefly Kuang Abdullah

Phase Behaviour, Formation and Characterization of Palm-Based Esters Nanoemulsion Formulation containing Ibuprofen

Palm-based esters, synthesized through enzymatic transesterification of palm oil fractions with oleyl alcohol have potential application in pharmaceutical formulations. The phase behaviour of palm-based esters containing ibuprofen with surfactant of different HLB values was investigated for topical delivery system. The surfactants were Tween 85, Tween 60 and Tween 80, and the palm-based esters were palm oil esters (POEs) and palm kernel oil esters (PKOEs). Ternary phase diagrams of palm-based esters: Ibuprofen/surfactant/water systems were constructed. Three distinct regions were observed in the phase diagrams; isotropic liquid region, L 1 , liquid crystalline region, L c and multiphase region, M. Nanoemulsions were prepared spontaneously by the addition of water to oil:ibuprofen/surfactant mixtures based on the ternary phase diagrams constructed. Formulations from the PKOEs:Ibuprofen/Tween 80/water systems were selected due to the presence of large isotropic liquid region, which suggested that this region was suitable to be used in producing nanoemulsions. Particle size analysis showed that the mean particle sizes of these formulations ranged from 10 nm to 70 nm. Zeta potential analysis for all formulations showed negative values from -4 to -8 mV. Stability studies showed that, after 4 h of stirring at room temperature (25°C), the formulations were stable under centrifugation test at 4000 rpm for 15 min. Stability under different storage temperature showed that at 25°C, the four formulations, F1, F2, F3 and F4 were stable with no phase separation for the duration of 1 month. However, when these formulations were stored at 45°C and 4°C, respectively, only F3 and F4 were observed to be stable. These two formulations have the potential to be used for topical delivery of ibuprofen.

Statistical Optimization of Process Parameters for Lipase-Catalyzed Synthesis of Triethanolamine-Based Esterquats Using Response Surface Methodology in 2-Liter Bioreactor

Lipase-catalyzed production of triethanolamine-based esterquat by esterification of oleic acid (OA) with triethanolamine (TEA) in n-hexane was performed in 2 L stirred-tank reactor. A set of experiments was designed by central composite design to process modeling and statistically evaluate the findings. Five independent process variables, including enzyme amount, reaction time, reaction temperature, substrates molar ratio of OA to TEA, and agitation speed, were studied under the given conditions designed by Design Expert software. Experimental data were examined for normality test before data processing stage and skewness and kurtosis indices were determined. The mathematical model developed was found to be adequate and statistically accurate to predict the optimum conversion of product. Response surface methodology with central composite design gave the best performance in this study, and the methodology as a whole has been proven to be adequate for the design and optimization of the enzymatic process.

Modification of palm kernel oil esters nanoemulsions with hydrocolloid gum for enhanced topical delivery of ibuprofen

Introduction During recent years, there has been growing interest in the use of nanoemulsion as a drug-carrier system for topical delivery. A nanoemulsion is a transparent mixture of oil, surfactant and water with a very low viscosity, usually the product of its high water content. The present study investigated the modification of nanoemulsions with different hydrocolloid gums, to enhanced drug delivery of ibuprofen. The in vitro characterization of the initial and modified nanoemulsions was also studied. Methods A palm kernel oil esters nanoemulsion was modified with different hydrocolloid gums for the topical delivery of ibuprofen. Three different hydrocolloids (gellan gum, xanthan gum, and carrageenan) were selected for use. Ternary phase diagrams were constructed using palm kernel oil esters as the oil, Tween 80 as the surfactant, and water. Nanoemulsions were prepared by phase inversion composition, and were gradually mixed with the freshly prepared hydrocolloids. The initial nanoemulsion and modified nanoemulsions were characterized. The abilities of the nanoemulsions to deliver ibuprofen were assessed in vitro, using a Franz diffusion cell fitted with rat skin. Results No significant changes were observed in droplet size (~16–20 nm) but a significant difference in polydispersity indexes were observed before and after the modification of nanoemulsions using gellan gum, carrageenan, and xanthan gum. The zeta potentials of the initial nanoemulsions (−11.0 mV) increased to −19.6 mV, −13.9 mV, and −41.9 mV, respectively. The abilities of both the initial nanoemulsion (T802) and the modified nanoemulsion to deliver ibuprofen through the skin were evaluated in vitro, using Franz diffusion cells fitted with rat skin. The in vitro permeation data showed that the modified nanoemulsion (Kp value of 55.4 × 10−3 cm · h−1) increased the permeability of ibuprofen 4.40 times over T802 (Kp value of 12.6 × 10−3 cm · h−1) (P < 0.05). Conclusion The modified nanoemulsion may be a promising vehicle to enhance the permeation of ibuprofen for topical delivery.

Forensic Characterization of Polycyclic Aromatic Hydrocarbons and Hopanes in Aerosols from Peninsular Malaysia

A forensic study on the characterization of polycyclic aromatic hydrocarbons (PAHs) and hopanes in atmospheric aerosols has been carried out on nine locations in peninsular Malaysia in July 2006. There were 18 individual PAHs and 16 individual hopanes detected in the samples. Total PAH concentrations ranged from 0.58 to 10.49 ng/m3, and hopanes ranged from 1.62 to 10.49 ng/m3. Source identification using diagnostic ratios suggests that the biomass burning and vehicular emissions are the main sources of PAHs in the samples. Additionally, the strong influence of crankcase oil incorporated in street dust was identified pointing out a significant source of hopanes in the study area.

INFLUENCE OF BATH TEMPERATURE AND PH VALUE ON PROPERTIES OF CHEMICALLY DEPOSITED CU4SNS4 THIN FILMS

Thin films of Cu4SnS4 semiconductors were prepared by chemical bath deposition technique in aqueous solutions. The effects of various bath temperatures (40, 50 and 60 °C) and pH values (pH 0.5, pH 1.0 and pH 1.5) on growth of films were reported. The structure and morphology characteristics of thin films of Cu4SnS4 grown on indium tin oxide glass substrates were investigated by X-ray diffraction and atomic force microscopy techniques. The optical properties were measured to determine the transition type and band gap value. The thin films produced were found to be polycrystalline with orthorhombic structure. The X-ray diffraction data showed that the most intense peak at 20 = 30.2° which belongs to (221) plate of Cu4SnS4. The films deposited at 50 °C were found to have the best photoresponse activity and smaller crystal size. At pH 1.5, the film showed well-covered entire substrate surface and the highest absorption values in AFM and optical study, respectively. The best condition to prepare good quality thin films can be carried out at 50 °C with pH 1.5. The bandgap value was found to be 1.4 eV with direct transition.