• Proceedings of the Botanical Society of Korea Conference
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• 2001.04a
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• pp.14-14
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• 2001

• Journal of Pharmaceutical Investigation
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• v.31 no.4
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• pp.225-232
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• 2001

The present study was carried out to observe the effect of liposome dispersed gel formulation (Lipogel) on topical delivery of ascorbyl palmitate (AsP). Neutral and negatively charged MLV liposomes containing AsP were prepared with dimyristoylphosphadtidylcholine (DMPC) and dicetyl phosphate (DCP), and dispersed to poloxamer gel matrix. In the hydrolysis study in rat's skin homogenates, AsP hydrolyzed to ascorbic acid (AsA) according to the first-order kinetics with the rate constant of $2.46{\times}10^{-2}\;min^{-1}$. In the passive skin penetration study using Franz diffusion cell, lipogel systems exhibited the greater values in the flux $(J_s)$ and the amount penetrated $(Q_p)$ compared to control hydrogels containing diethyleneglycol monoethyl ether $(Transcutol^{\circledR})$ as a solubilizing agent and a penetration enhancer for AsP. The total amount penetrated $(Q_{Total})$, which is expressed as a summation of $Q_P\;and\;Q_L$, for lipogel system was about 1.4 times higher in average than that of control hydrogel. However the amount localized in the skin $(Q_L)$ was similar in both formulations. As a result, lipogel system enhanced the skin penetration of AsP, possibly due to the increase in local concentration of AsP by preferential adsorption of liposome to the skin and the enhancing effect of phospholipid in liposome composition. Moreover it was expected that the penetrated AsP would generate AsA during skin penetration by the skin esterase. In conclusion, lipogel formulation was considered as a good candidate for topical delivery of AsP.

• The Korean Journal of Physiology
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• v.10 no.1
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• pp.61-66
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• 1976

Rectal temperature, skin temperature and oxygen consumption were measured in five women divers during diving under two conditions a) wearing a cotton bathing suit and b) wearing a diving suit and the following results were obtained. 1. The duration of the diving period was 30 min with the cotton bathing suit whereas it was above 120 min with the diving suit. 2. The average rectal temperature fell to $34.5^{\circ}C$ after 30 min of diving with the cotton bathing suit. On the other hand, with the diving suit, immediately after submersion, the rectal temperature rose about $3^{\circ}C$ and remained at about $39^{\circ}C$ throughout the diving period of 120 min. 3. Average mean skin temperature during diving was $11^{\circ}C$ and $21^{\circ}C$ with cotton bathing suit and with the diving suit, respectively. The mean body temperature fell to $25^{\circ}C$ with the cotton bathing suit while it reached $32^{\circ}C$ with the diving suit at the end of each diving period. 4. Oxygen consumption during diving was three fold of the pre-dive level with the cotton bathing suit but it was two fold with the diving suit. 5. Total extra heat loss was 323 kcal during 120 min of diving with the diving suit. On the contrary, with the cotton bathing suit, it was 528 kcal for 30 min, These results may suggest that the prolongation of the diving period with the diving suit is primarily due to maintenance of core temperature at more or less physiological level as a result of reduction in conductive heat loss from the body surface to the water and the Preferential distribution of blood in the core area.