• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1997년도 춘계학술대회
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• pp.116-116
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• 1997

Complex formation of practically insoluble dexamethasone dipropionate (DDP) with ${\beta}$-cyclodextrin (${\beta}$-CD), dimethyl-${\beta}$-cyclodextrin (DMCD), trimethyl-${\beta}$-cyclodextrin (TMCD), 2-hydroxypropyl-${\beta}$-cyclodextrin (HPCD) and sulfobutyl ether ${\beta}$-cyclodextrin (SBCD) in water was investigated by solubility method at various temperatures. Water solubility of DDP was found to be 1.78 $\mu\textrm{g}$/$m\ell$ at 37$^{\circ}C$. Propylene glycol (PG)-water cosolvent increased the solubility of DDP, but the solubilization was not sufficient (8.93 $\mu\textrm{g}$/$m\ell$ in 20% PG). The addition of CD markedly increased the solubility of DDP in water, and A$\sub$L/ type phase solubility diagrams were obtained with ${\beta}$-CD, TMCD, HPCD and SBCD, where the apparent stability constants of the soluble complexes at 25$^{\circ}C$ were determined to be 1388, 216, 1054, and 1992 M$\^$-1/, respectively. However, DMCD remarkably increased the solubility of DDP, and showed an A$\sub$P/ type diagram, suggesting that DMCD forms a soluble complex of high order with DDP. The stability constant for the DDP-DMCD complex at 25$^{\circ}C$ was determined to be 19132 M$\^$-1/. The thermodynamic parameters were calculated for the inclusion complex formation in aqueous solution. CD (1${\times}$10$\^$-2/M) remarkably decreased the partition coefficients of DDP between isopropyl myristate/water in the order of TMCD < ${\beta}$-CD < HPCD < SBCD < DMCD, and in squalane/water system in the order of HPCD < TMCD < ${\beta}$-CD < DMCD < DMCD $\leq$ SBCD. This finding represents that, in a o/w type cream, cyclodextrin complexation with DDP may result in high concentration of DDP in aqueous phase. The permeation of DDP through a cellophane membrane was highly suppressed by the addition of CD, and the degree of suppression was different among CDs, indicating that CD may control the skin permeation of DDP. The dissolution rates of solid dispersions with CDs were much faster than those of drugs alone and corresponding physical mixtures. All DDP-CD solid dispersions exceeded the equilibrium solubility. Consequently these results suggest that complex formation of DDP with CDs may provide useful means to markedly enhance the solubility, and CDs are useful in the semi-solid preparations such as creams and gels for topical application.

• 한국응용과학기술학회지
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• 제30권4호
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• pp.679-687
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• 2013

4-클로로벤조산의 가용화현상을 이용하여 순수양이온성 계면활성제(DTAB, TTAB, CTAB), 비이온성 계면활성제(Tween-20, Tween-40, Tween-80) 및 이들 혼합계면활성제(TTAB/Tween-20, TTAB/Tween-40, TTAB/Tween-80)의 임계미셀농도(CMC)값과 반대이온 결합상수값(B)를 온도 284 K에서 312 K까지 변화를 주면서 UV/Vis 분광광도법과 전도도법으로 측정하였다. 온도에 따른 CMC와 B값의 변화를 측정하여 미셀화현상에 대한 여러 가지 열역학 함수값(${\Delta}G^o{_m}$, ${\Delta}H^o{_m}$, 및 ${\Delta}S^o{_m}$)을 계산하고 분석 하였다. 그 결과 측정범위 내에서 ${\Delta}G^o{_m}$값은 모두 음의 값을 나타내었다. 그러나 ${\Delta}H^o{_m}$과 ${\Delta}S^o{_m}$값은 계면활성제의 종류와 계면활성제분자에서 탄소사슬의 길이에 따라 양의 값 혹은 음의 값을 나타내었다.