Advances in Science and Technology Vol. 121

Abstract: Clove oil is a volatile oil that is extracted from clove buds of Syzygium aromaticum. It was reported for antibacterial and antifungal activities. Microemulsions (ME) are a stable emulsion system composed of oil, surfactant mixture (SM, surfactant and co-surfactant) and water. In this study clove oil-loaded microemulsions (CM) were fabricated using Tween 20 as surfactant. Co-surfactants used in CM were ethanol and isopropanol. CM with different concentrations of clove oil (10-50% w/w) and SM (40-80% w/w) at Tween 20:co-surfactant ratios of 1:2 were formulated and characterized for their physico-chemical properties. All CM was clear liquid with thermodynamic stability. The size of all CM prepared from both ethanol and isopropanol was less than 100 nm. At lower oil and SM concentrations, the CM was o/w ME. When the concentration of oil or SM increased, the conductivity values decreased to less than 10 μS/cm indicating that the obtained CM was w/o ME. All CM formulations exhibited strong antioxidant activity as tested by the DPPH scavenging method (92.79 - 94.95% inhibition). Changing the type of co-surfactants (ethanol or isopropanol) or changing the oil to co-surfactant ratio did not significantly alter the antioxidant activity. Therefore, considering both physicochemical properties and antioxidant activity of CM, the CM containing 10% clove oil is the recommended formulation for commercial development.

Abstract: Andrographolide (AGP), a major component of Andrographis paniculata (Burm.f.) Nees (AP), has several biological activities. Nevertheless, poorly water solubility and low bioavailability of AGP lead to decrease clinical benefits. Therefore, this study aims to develop of AP extract-chitosan solid dispersion using central composite design (CCD) to enhance AGP release. AP crude extract was obtained by Soxhlet extractor using 85%v/v ethanol as a solvent extraction. Then, AP extract, chitosan, and poloxamer 188 in the concentrations provided by CCD was spray dried. The in-vitro release of AP extract-chitosan spray dried powder was studied by dissolution equipped with enhancer cell in 200 ml of 50%v/v methanol at 37°C and 50 rpm of paddle speed. Samples were withdrawn at 0.25-96 hours and then determined AGP by UV spectrophotometer at 224 nm. The results of CCD indicated that %ethanol and %AGP from concentrated AP extract had significant (P < 0.05) effect on the concentration of AGP released at 5 hours. The optimum formulation composed of %ethanol of 18.25, %AGP in extract of 0.38, and %poloxamer 188 of 0.17 resulted in more AGP concentration at 5 hours than 50 μg/mL. Release kinetic study revealed that %release of the optimal formulation was best fitted to first order kinetic. In powder X-ray diffraction, intensity of AGP characteristic peaks in the optimal formulation decreased by 7.17-25.69 times compared with AGP standard. It was concluded that the optimal formulation of AP extract-chitosan solid dispersion could improve AGP release due to changing crystalline AGP to amorphous state.

Abstract: Antibiotic-resistant has emerged without new drug challenges. Polymyxin B (PMB) was the last resort therapy for multiple-drug resistant Gram-negative bacteria. However, the toxicity of PMB including nephrotoxicity (61%) and neurotoxicity (7%) was dose-limitation. PMB-based sodium deoxycholate sulfate (SDCS) formulations were prepared in the 2-different mole ratios of SDCS to PMB (5:1 and 10:1). Particle size, zeta-potential, and drug content were evaluated. The biocompatibility of PMB formulations was investigated with normal human primary renal proximal tubule epithelial cells (PCS-400-010), human kidney epithelial cell lines (HEK 293T/17), human kidney cell lines (WT 9-12), macrophage-like cells (RAW 264.7) and red blood cells (RBC). PMB formulations had smaller particle sizes and lower zeta-potential when compared to PMB. PMB content presented from 97-100% after lyophilization. PMB-SDCS formulations revealed lower toxicity to cell lines than PMB, especially SDCS: PMB (5:1) and low lysis of RBC. PMB-SDCS mixture had better biocompatibility than those PMB and SDCS alone.

Abstract: Colistin has its problem with nephrotoxicity despite its capability for combatting multi-drug resistant gram-negative bacteria. Sodium deoxycholate sulfate (SDCS) has been shown to increase the safety profile of nephrotoxic drugs. This study aimed to explore the antimicrobial activity of colistin-SDCS versus free colistin against P. aeruginosa and investigate their cytotoxicity on kidney cells. The colistin micelles were formulated with SDCS followed by lyophilization and their properties were analyzed. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of colistin were determined using the broth microdilution method. The static time-kill kinetics were also employed to monitor the bactericidal activity of formulation over time. The cytotoxicity of formulations was analyzed using MTT colorimetric assay against kidney cells. The colistin-SDCS dry-powder was stable after reconstitution and resulted in 240 to 297 nm in particle size with the zeta potential of -22.8 to -23.4 mV. The colistin-SDCS formulations showed similar antibacterial activity against P. aeruginosa to pure colistin. MIC and MBC were 7.81 and 15.63 µg/mL, respectively. The static-time kill results displayed slightly better bactericidal activity at 24 h. The viability of kidney cells exposure to colistin-SDCS micelle was higher than that of pure colistin.

Abstract: Ocular drug delivery by topical application is the most popular for the treatment of ocular diseases. However, a number of inherent anatomical and physiological ocular barriers limit the bioavailability of the drug administered by topical application. To overcome this limitation, dissolving polymeric microneedles (dMNs) have been used to create transport pathways and enhance the permeability of ocular drugs with minimal invasion. The aim of this study was to design and evaluate Optimized dMNs for ocular delivery of a hydrophilic drug using a computational design strategy. Polyvinyl alcohol/hyaluronic acid mixture was used as the dMN-forming polymers. A micromolding technique was used to fabricate the dMNs. The dMNs were evaluated for physical appearance using a digital microscope, mechanical strength using a texture analyzer. Moreover, the dissolution time, penetration depth, and permeation study on the porcine corneal tissues were investigated. The results showed that the optimal dMNs formulation was 20%PVA and 5%HA in a 1:5 weight ratio. The physical appearance showed conical microneedles with an average 601.23 ± 1.01 μm in height and 300.02 ± 0.23 μm in the base width. The optimal dMNs showed a maximum tolerance force of about 33.70 ± 0.30 N and created micro-channels on corneal tissues surface with the depth about 134.71±16.51 μm. The optimal dMNs can be completely dissolved in the corneal tissue within 3 min with high % permeation and flux of fluorescein sodium about 10.10 ± 0.55% and 14.21 ± 1.45 μg/cm²/h, respectively. In conclusion, the optimal dMNs showed high efficiency to enhance ocular delivery of the hydrophilic drug with safe and minimal invasion for ocular tissue.

Abstract: The aim of this work was to develop and validate RP-HPLC method for quantification of 4 major polyphenolic compounds of mulberry leaf infusion. The mulberry leaf samples were extracted by simulation of tea infusion beverage preparation. HPLC-DAD analysis combined with column C-18 150 mm x 4.6 mm, 2.7 μm was used to determine bioactive polyphenols such as chlorogenic acid, caffeic acid, rutin, and quercetin. The optimal conditions involved the flow rate of mobile phase at 0.3 ml/min with gradient elution of 0.1% formic acid in water and methanol, column temperature at 35 °C, 2 μl injection volume, and the detection wavelength at 320 nm (chlorogenic acid and caffeic acid) and 360 nm (rutin and quercetin). The retention times of chlorogenic acid, caffeic acid, rutin, and quercetin were 25.68, 28.03, 33.97 and 39.11 minutes, respectively. Analysis of four bioactive compounds was found to be linear with a correlation coefficient > 0.99 each at the tested concentration. All other validation parameters that represented accuracy and precision met the AOAC requirements. The developed analytical method was specific, robust, and accurate for simultaneous determining the stated compounds in mulberry leaf extracted with hot water. Moreover, this method could provide the chromatographic profiles of specific cultivar from specific source that could be used to control the quality of mulberry leaf tea products. Different cultivars and different origins of mulberry leaf in this study were also found to present different content of chlorogenic acid, caffeic acid, and rutin. No quercetin was found in the studied samples.