• Proceedings of the PSK Conference
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• 2003.10b
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• pp.234.1-234.1
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• 2003

The effects of vehicles and penetration enhancers on the in vitro permeation of ketorolac tromethamine (KT) across excised hairless mouse skins were investigated. Among pure vehicles examined, propylene glycol monolaurate (PGML) showed the highest permeation flux, which was 94.3${\pm}$17.3 mg/cm$^2$/hr. Even though propylene glycol monocaprylate (PGMC) alone did not show high permeation rate, the skin permeability of DT was markedly increased by the addition of diethylene glycol monoethyl ether (DGME); the enhancement factors were 19.0 and 17.1 at 20 and 40% of DGME, respectively. (omitted)

• Clean Technology
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• v.17 no.3
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• pp.244-249
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• 2011

We synthesized low molecular-weight polymers bearing hydrophobic and hydrophilic parts in a chain through $CO_2$/propylene oxide copolymerization. When hydrophilic poly (ethylene glycol) bearing -OH group (s) at the end group (s) was added as a chain transfer agent in the $CO_2$/propylene oxide copolymerization catalyzed by a highly active catalyst, block polymers were formed. If poly (ethylene glycol) (PEG) bearing -OH group only at an end was fed, PEG-block-PPC diblock copolymer was obtained. When PEG bearing -OH group at both ends was fed, PPC-block-PEG-block-PPC triblock copolymer was obtained. We confirmed formation of block copolymers by $^1H$-NMR spectroscopy and GPC studies.

• Membrane Journal
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• v.14 no.3
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• pp.250-257
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• 2004

PEG(poly(ethylene glycol)) acrylate/PPG(poly(propylene glycol)) acrylate (PEG/PPG) was prepared using UV induced photopolymerization method to investigate gas permeation properties of the membrane. The effect of PPG content on the solubility, diffusivity, and permeability of $CO_2$, $O_2$, and $N_2$ in PEG/PPG membrane is reported at $25^{\circ}C$ and $35^{\circ}C$. PEG/PPG (9:1) membrane exhibits $CO_2$ permeability coefficient of 28.9 barrer and $CO_2$/$N_2$ pure gas selectivity of 57.9 at $25^{\circ}C$. Permeability coefficient of increased with increasing with PPG content in the membrane. PEG/PPG (5:5) membrane shows $CO_2$ permeability coefficient of 78.9 barrer and $CO_2$/$N_2$ pure gas selectivity of 33.2 at $25^{\circ}C$.

• Journal of Embryo Transfer
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• v.11 no.1
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• pp.35-40
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• 1996

This study was carried out to select the best cryoprotectant and to establish optimal concentration of the cryoprotectant in ultrarapid freezing of mouse 4-cell embryos and morulae, respectively. We investigated survival of ultrarapid frozen embryos according to various cryoprotectants such as glycerol, ethylene glycol, propylene glycol and dimethyl sulfoxide (DMSO). Suvival of the embryos frozen at different concentrations (3.0, 4.0 and 5.0 M) of indivisual cryoprotectant was also tested. Preimplantation developmental rate (96.3%, 83/86) of 4-cell mouse embryos treated with 4.0 M ethylene glycol after ultrarapid freezing and thawing was higher than those of other cryoprotectants (glycerol, propylene glycol and DMSO). In the ultrarapid freezing of mouse morulae, the highest developmental rate (98.8%, 89 /90) of the embryos to blastocysts was shown in the group of 5.0 M glycerol. Thus, these results demonstrate that 4.0 M ethylene glycol and 5.0 M glycerol are optimal for ultrarapid freezing of 4-cell mouse embryos and morulae, respectively.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.957-963
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• 1999

Effects of cryoprotectants on protein denaturation of soybean curd, tofu, during frozen storage were examined. A whole-coagulated non-press tofu was prepared by adding 2% of isolated soybean protein to soy milk in order to prevent loss of added cryoprotectants. The cryoprotectants added were glocose, glycerol, sorbitol, propylene glycol, and tripolyphosphate. The texture characteristics of soybean curds before and after frozen storage were measured by sensory evaluation and Texture analyzer, and the results were evaluated by response surface methodology (RSM). Glucose, glycerol, sorbitol, and sodium tripolyphosphate were effective as single cryoprotectant, and the mixtures of glucose and sodium tripolyphosphate, and sorbitol and propylene glycol were also effective in minimizing textural change during freezing. Overall, the mixture of cryoprotectants were more effective than single cryoprotectant. According to the RSM, the maximum effect of cryoprotectants in minimizing textural changes during freezing was obtained with the mixture of 2.1% glucose, 6.7% glycerol, 2.1% sorbitol, 0.4% propylene glycol, and 0.3% sodium tripolyphosphate. However, considering the sensory acceptability, the optimum use of cryoprotectants in frozen tofu was 1% glucose, 2% glycerol, 1% sorbitol, 0.2% propylene glycol, and 0.5% sodium tripolyphosphate.

• Archives of Pharmacal Research
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• v.25 no.3
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• pp.392-399
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• 2002

The effects of vehicles and penetration enhancers on the in vitro permeation of melatonin through dorsal hairless mouse skin were investigated. Propylene glycol laurate (PGL), isopropyl myristate (IPM), propylene glycol monolaurate (PGML) and propylene glycol monocaprylate (PGMC) showed high permeation fluxes and PGL, PGML and PGMC decreased lag time significantly. In both of the binary co-solvents of diethylene glycol monoethyl ether (DGME)-PGL and DGME-IPM, the highest fluxes were achieved at 20% of DGME, which were $10.5{\pm}1.5$ and $9.1{\pm}2.4{\;}{\mu\textrm{g}}/cm^2/h$, respectively. Among fatty acids used as a permeation enhancer, capric acid and oleic acid in DGME-PGL (80:20 v/v) showed relatively high enhancing effects. Capric acid also shortened the lag time of melatonin from $2.4{\pm}0.7{\;}to{\;}1.3{\pm}0.2{\;}h$. Oleic acid, however, failed to shorten the lag time. Therefore, for effective solution formulations in terms of permeation flux and lag time, capric acid-containing DGME-PGL (80 : 20 v/v) could be used to enhance the skin permeation of melatonin.

• Journal of the Korean Society of Tobacco Science
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• v.27 no.1 s.53
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• pp.31-39
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• 2005

This study was conducted to evaluate the characterization of the pyrolysis products of propylene glycol(PG) and glycerine alone and together with tobacco. The weight change of the samples during the pyrolysis was measured by a thermal analyzer(STD-2960). The pyrolysis products were determined by GC/MS after pyrolysis using a curie-point pyrolyzer(CPP, $220^{\circ}C,\;420^{\circ}C,\;650^{\circ}C,\;and\;920^{\circ}C$) and a double-shot pyrolyzer(DSP, $220^{\circ}C,\;420^{\circ}C,\;650^{\circ}C,\;and\;800^{\circ}C$), respectively. The pyrolysis products from tobacco with and without the addition of PG($2\%$) and glycerine($2\%$ were assayed for its pyrolytic behavior. The results showed that a dramatic change in weight of PG and glycerine was observed at $175^{\circ}C\;and\;249^{\circ}C$, respectively. PG and glycerine showed different patterns for their pyrolysis products according to the method of pyrolysis. Namely, the change rate in pyrolysis with DSP was much higher than that of CPP at above $650^{\circ}C$. The major pyrolysis products of PG were propene, acetaldehyde, propanal, and acetol; the major pyrolysis products of glycerine were 2-propenal, 2-propenol, acetol, and acetic acid. In the pyrolysis experiments of tobacco added PG and glycerine, the pyrolysis products of PG and glycerine weren't detected additionally, except for diethyleneglycol diacetate. From these results, it can be concluded that the PG and glycerine added to tobacco would not be expected to pyrolyse extensively during smoking.

• Polymer(Korea)
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• v.30 no.2
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• pp.152-157
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• 2006

Anionic or Zwitter-ionic waterbone polyurethanes (WPU) based on mixtures of hydroxy terminated poly-butadiene and poly(propylene glycol) were prepared and their physical properties were characterized. Particle size of WPU increased with increasing the content of HTPB. It was observed that the microphase separation of soft segments and hart segments increased with increasing the content of HTPB in the WPUs. Zwitter-ionic WPU showed stronger hydrogen bonds between molecules than anionic WPU after drying. Polyurethane films obtained after drying of WPUs exhibit besmechanical properties when the HTPB content among polyols for WPUs were 25wt%. It is postulated that such mechanical properties resulted from different microphase separation of soft segments and hard segments of polyurethane films obtainec after drying of WPUs.

• Polymer(Korea)
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• v.39 no.2
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• pp.247-255
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• 2015

Poly(1,2-propylene glycol adipate) (PPA) was used as an environmentally friendly plasticizer in flexible poly(vinyl chloride) (PVC). Thermal, mechanical, and rheological properties of the PVC/PPA blends were characterized by differential scanning calorimetry, dynamic mechanical analysis, tensile test, scanning electron microscopy and small amplitude oscillatory shear rheometry. The results showed that PPA lowered the glass transition temperature of PVC. The introduction of PPA could decrease tensile strength and Young's modulus of the PVC/PPA blends; however, elongation-at-break was dramatically increased due to the plastic deformation. The plasticization effect of PPA was also manifested by the decrease of dynamic storage modulus and viscosity in the melt state of the blends. The results indicated that PPA had a good plasticizing effect on PVC.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.201-212
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• 2003

The heartwood extract of Artocarpus lakoocha Roxb., which contains a potent tyrosinase inhibitor oxyresveratrol, was evaluated for its melanin-reducing efficacy in both guinea pigs and human volunteers. After 4 week-daily application of the extract dissolved in propylene glycol to the back of guinea pigs, significant reduction in melanin content was detected, with the effect greater than 3% kojic acid and solvent propylene glycol (P < 0.05). The extract was subsequently tested in female volunteers (3 groups of 20 subjects) using a parallel clinical trial with self-control. The first group received the A. lakoocha solution in propylene glycol whereas the second and the third group respectively received 0.25% licorice extract and 3% kojic acid in the same solvent. The subject in each group twice daily applied the test solution on one arm whereas the remaining arm was applied with only propylene glycol (self-control) for 12 weeks. The A. lakoocha extract was found to be the most effective agent, giving the shortest onset of significant whitening after only 4 weeks of application (P < 0.05), followed by 3% kojic acid (8 weeks) and 0.25% licorice extract (10 weeks). The whitening effect also increased with time, with the highest extent observed with A. lakoocha at week 12. The in vitro antityrosinase activity of A. lakoocha extract decreased with time upon storage at room temperature but could be stabilized by a combination of several antioxidants. In conclusion, the heartwood extract of A. lakoocha appeared to have promising potential for use as an effective and economical skin-whitening agent.