Advanced Materials Research Vol. 1060

Abstract: Methacrylic acid copolymers crosslinked with 0.25-16 % divinylbenzene were synthesized by free radical polymerization using benzoyl peroxide as an initiator. The products were washed, dried and passed through a 80-mesh sieve prior to determining their infrared spectra, swelling capacity in water and disintegrant efficacy for microcrystalline cellulose (MCC) placebo tablet. The crosslinked methacrylic acid and divinylbenzene copolymers were successfully prepared as indicated by IR spectra, yielding around 50-80 %. The sieved particles of copolymers were white to faint yellow. In contact with water, they hydrated and swelled, where their swelling capacity was lowered with increasing the level of crosslink (divinylbenzene) in the copolymer structure. The copolymer with 0.25 % crosslink caused the MCC tablet to disintegrate fastest (1.2 min), corresponding to its highest swelling capacity. The disintegration efficacy increased with an increase in copolymer concentrations, but decreased with an increase in compression forces.

Abstract: Hydrophile–lipophile balance (HLB) is a key parameter for formulation of emulsions. Recently, modified coconut oil (MCO) was successfully developed as antimicrobial oil and was attempted to use as active ingredient in emulsions. Therefore, the aim of this study was to determine the required HLB of MCO. The emulsions was produced with different ratios of emulsifier mixtures of Tween^® 80 and Span^® 80 , giving HLB from 4.3 to 15.0 and was investigated in respect of their emulsions stability. The result showed that an emulsion with HLB value of 12 demonstrated the most stable in terms of smallest droplet size and minimal size distribution. The stability was also later confirmed by centrifugation and temperature cycling. The emulsions which possessed HLB values closed to required HLB demonstrated minimal creaming and cracking upon accelerated stability study. In conclusion, this study could provide the guideline for formulation of the stable MCO emulsions which may be further developed into suitable dosage form.

Abstract: Binary solid dispersions of manidipine hydrochloride (MDP) and polyethylene glycol (PEG) 4000 are prepared by melting method. Drug loading and process temperature are varied in the range of 5-30% and 150-210°C, respectively. After melting, only the formulation using 5% MDP and process temperature of 210°C showed yellow clear solution and halo pattern of powder X-ray diffractograms with the absence of peaks. These results indicated that the higher process temperature (210°C) can melt all MDP powders and provide the amorphous product. Moreover, only the higher carrier content can change the crystalline form of MDP to the amorphous form. A clear, solid solution could not be prepared when the drug loading was higher than 5%. In this study, the melting technique avoiding the use of organic solvent was successfully applied to prepared binary solid dispersion.

Abstract: Melt reaction of poly (ethylene glycol) and alginic acid (guluronate-rich and mannuronate-rich) was studied. The poly (ethylene glycol) was end-capped with reactive amino group while the sodium alginate was converted to alginic acid before melt reaction. The melt reaction kinetics of poly (ethylene glycol) and alginic acid were monitored by differential scanning calorimetry. The reaction temperatures were ranged between 75 and 96 °C, below the degradation temperature of both parent polymers. The reactive amino group of poly (ethylene glycol) reacted with carboxyl group of alginic acid. The rate of reaction increased with reaction temperature.

Abstract: Poly(lactic acid) (PLA) has a variety of applications. It has been widely used in the biomedical and pharmaceutical fields due to its biocompatibility and biodegradability. Polyethylene glycol (PEG) is used as an inactive ingredient in the pharmaceutical industry as a solvent, plasticizer, surfactant, ointment base, suppository base, tablet lubricant and capsule lubricant. The aim of this study was to determine the effect of temperature change on PLA porous matrix film fabricating by solvent casting method with an addition of PEG400 to improve and increase the pore interconnectivity. Their mechanical properties such as tensile strength (TS) and % elongation at break (%E) and morphology were investigated. Porous films were prepared at 4 °C for 24 h and dry at room temperature for 24 h (4CRT), 4 °C for 24 h and dry at 60 °C for 24 h (4C60C), -20 °C for 24 h and dry at room temperature for 24 h (-20CRT), -20 °C for 24 h and dry at 60 °C for 24 h (-20C60C), -80 °C for 24 h and dry at room temperature for 24 h (-80CRT), and -80 °C for 24 h and dry at 60 °C for 24 h (-80C60C). 4C60C exhibited the highest strength and toughest, however all of samples showed the quite soft behavior. From topography study they displayed the different porous structure which sample of 4C60C displayed the smallest porous structure. Therefore, the temperature change between the fabrication processes affected the TS, %E and morphology structure of PLA porous matrix films.

Abstract: Menthol was used as sublimate eutectic compound to prepare the volatile eutectic solvent by mixing with camphor, borneol or N-Ethyl-5-methyl-2-(1-methylethyl) cyclohexanecarboxamide (WS-3). The system of menthol:camphor, menthol:borneol and menthol:WS-3 in various ratio (1:9 to 9:1) was characterized. The 5:5 menthol:camphor system showed the highest evaporation rate. Ibuprofen dissolved in eutectic solvent was used as internal phase of emulsion whereas tween80 was used as emulsifier. Eutectic solvent was evaporated to induce the transformation of emulsion droplet to small particle. Eutectic could be used as solvent for preparing small size suspension (14.81±0.44 µm) without organic solvent used.

Abstract: This work was aimed to develop thermally crosslinked chitosan/PVA nanofiber mats. The CS/PVA nanofibers were fabricated using elctrospinning process. The appropriate crosslinking temperatures and crosslinking times in order to thermally crosslinked CS/PVA nanofiber and physicochemical properties of the thermally crosslinked nanofibers were investigated. The morphology of the nanofiber mats was investigated by scanning electron microscopy (SEM). The water insolubilization and FTIR were employed to evaluate the success of crosslinking. Increasing the crosslinking time and temperature, the crosslink was increased, thus causing a decrease of water solubilization. The temperature and time for successful crosslinking were 180-200 °C and 0.5-5 h, respectively.

Abstract: Seven groups of herbal drinks including gum karaya, Indian gooseberry, Noni Indian mulberry, cat's whiskers, prickly-leaved elephant's foot, black galingale, and Ling zhi mushroom contain a variety of bioactive compounds such as polysaccharides, terpenes, saponins, and flavonoids. The extracts of these plants have several biological activities such as analgesic, anti-inflammatory, antibacterial, antioxidant and chemoprotective activities that can promote health. The popular uses of herbal drinks in Thailand raise the question about safety of their products, especially for heavy metal contamination. The concentrations of heavy metals such as As, Pb, Cu, Zn, Fe, and Cd in twenty one samples from seven groups of herbal drinks were determined by ICP-MS. None of herbal drinks passed the permissible limits under the Notification of Ministry of Public Health (No. 214) B.E. 2543 (2000) Re: Beverages in Sealed Container by the virtue of the Food Act B.E. 2522 (1979), Thailand. Moreover, the concentrations of Pb and Zn in all analyzed samples were higher than the permissible limits. The concentrations of Fe in almost all analyzed samples as well as the concentrations of As, Cd, and Cu in some analyzed samples were higher than the permissible limits. The levels of heavy metals found in this study raise concerns, not only for the safety of Thai consumers, but also the quality of herbal drinks available in Thailand.

Abstract: A combination of liquid-liquid extraction (LLE), column chromatography (CC) and gas chromatography-flame ionization detector (GC-FID) were performed to analyze different monolaurin (ML) concentrations in the solution preparations composed of modified coconut oil (MCO). LLE with dichloromethane has been used for the first time to extract ML from solution preparations. The resulting extract was individually purified by CC using silica gel to remove other interfering excipients. ML was detected by TLC and quantified using GC-FID. The combination method is simple and inexpensive and might be used with solution preparations composed of MCO.

Abstract: The phytotoxic effects of leaves and seeds from Annona squamosa extracts on lettuce (Lactuca sativa L.) seeds and Mimosa pigra were evaluated. A. squamosa leaf dichloromethane extracts reduced germination and seedling growth of lettuce seeds. In field study, A. squamosa leaf dichloromethane extracts was applied on M. pigra after growing. Fresh weight of M. pigra was decreased with increasing concentrations of leaf dichloromethane extracts. These results suggest that dichloromethane extracts from leaves of A. squamosa may have growth inhibitory substances. Thus, our study indicated that leaf dichloromethane extracts have phytotoxic activity which could be utilized as bioherbicide for future weed control.