• Journal of Oral Medicine and Pain
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• 제35권4호
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• pp.229-235
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• 2010

일반적으로 약물은 경구투여를 우선으로 한다. 그것은 환자에게 투여하기가 가장 쉬운 방법이기 때문이다. 하지만 경구투여를 하는 경우 인체에서 약물이 분해 및 흡수되면서 거치는 과정 중에 상당수가 없어지고 약효를 발휘하는 부분은 그다지 많지 않다. 그러다 보니 적절한 혈중 농도를 유지하기 위하여 실제 필요한 약물의 양보다 많은 양을 투여하게 되므로, 부수적으로 따라다니는 약의 부작용 또한 증가하게 된다. 피부질환의 경우에는 약물의 흡수를 돕도록 하는 많은 첨가물과 함께 개발된 외용제가 있다. 대부분 크림형태로 시판되고 있으며 약효를 내는 용량을 피부에 도포하였을 때 전신으로 흡수되는 양은 많지 않아 부작용이 적은 것이 장점이다. 구강점막은 자연적인 barrier가 많은 피부와 달리 혈관까지 도달하는 길이가 짧고, 도포가 어려운 장점막과 달리 접근성이 용이하다. 따라서 도포용 약물의 개발이 많이 시도되고 있으나 타액에 의해 많은 부분이 세척되어 없어지거나 타액속의 물질들로 인하여 변질이 일어나고 있어 피부와 같은 크림형 제제의 개발이 어려운 실정이다. 따라서 현재 판매되고 있는 구강내 외용제는 그 수가 매우 제한되어 있다. 도포용 약물을 개발하여 오래 구강점막에 부착하게 하는 것이 용이하지 않으므로 임상가들이 약물을 용액 형태로 사용하여 환자에게 도포하고 있다. 이러한 용액을 머금고 있다가 뱉어내게 하는 가글형태의 약물도포 또한 그 약효가 인정되고 있다. 따라서 현재 임상에서 도포형태로 사용하고 있는 약물의 종류와 효과, 그리고 일반적인 경구투여 약물을 적절한 용해제를 선택하여 용액으로 사용하였을 때 임상적으로 기대할 만한 약효를 발휘할 수 있을지에 대하여 연구해 본다.

• Journal of Pharmaceutical Investigation
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• 제27권4호
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• pp.303-311
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• 1997

Proliposomal patch of clenbuterol, ${\beta}_2-agonist$ bronchodilator, was prepared and its feasibility as a novel transdermal drug delivery system was examined. Proliposomal granules containing clenbuterol was prepared by a standard method using sorbitol and lecithin with (Rx 2) or without cholesterol (Rx 1). The porous structure of sorbitol in the proliposomes was maintained allowing tree flowability of the granules. Following contact with water, the granules were converted probably to liposomes almost completely within several minutes. It indicates that proliposomes may be hydrated, when they are applied on the skin under occlusive condition in vivo, by the sweat to form liposomes. Clenbuterol release from Rx 1 and Rx 2 proliposomes to pH 7.4 isotonic phospate buffer (PBS) across cellulose membrane (mol. wt. cut-off of 12000-14000) was retarded significantly compared with that from the mixture of clenbuterol powder and blank proliposomes. Interestingly, proliposomes prepared with lecithin and cholesterol (i.e., Rx 2 proliposomes) showed much more retarded release of clenbuterol than proliposomes prepared only with lecithin (i.e.. Rx 1 proliposomes), indicating that clenbuterol release from proliposomes can be controlled by the addition of cholesterol to the proliposomes. Proliposomal patches were prepared using PVC film as an occlusive backing sheet, two sides adhesive tape (urethane, 1.45 mm thickness) as a reservoir for proliposome granules and Millipore MF-membrane (0.45 mm pore size) as a drug release-controlling membrane. Rx 1 or Rx 2 proliposomes containing 4.6 mg of clenbuterol were loaded into the reservoir of the patch. Clenbuterol release from the patches to pH 7.4 PBS was determined using USP paddle (50 rpm)-over-disc release method. Clenbuterol release from the proliposomal patches was much more retarded even than from a matrix type clenbuterol patch (Boehringer Ingelheim ltd). Being consistent with clenbuterol release from the proliposomal granules, the release from the patches was highly dependent on the presence of cholesterol in the proliposomes : Patches containing Rx 2 proliposomes showed several fold slower drug release than patches containing Rx 1 proliposomes. When the patch containing Rx 1 proliposomes was applied on to the back of a hair-removed rat, clenbuterol concentration in the rat blood was maintained during 6-72 hrs. Transdermal absorption of clenbuterol from the patch was accelerated when the patch was prehydrated with 50 ml of pH 7.4 PBS before topical application. Above results indicate that sustained transdermal delivery of clenbuterol is feasible using proliposomal patches if the cholesterol content and pore size of the release rate-controlling membrane of patches, for example, are appropriately controlled.

• Journal of Pharmaceutical Investigation
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• 제34권2호
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• pp.107-114
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• 2004

External lyogels containing prostaglandin $E_1$ ethyl ester $(PGE_1-EE)$, a prodrug of prostaglandin $E_1\;(PGE_1)$ as a therapeutic agent for erectile dysfunction, were formulated to overcome the aqueous instability and enhance the percutaneous absorption. Lyogels of $PGE_1-EE$ were prepared with ethanol (EtOH)/proplyene glycol (PG) cosolvent system as a vehicle, cineol as an enhancer, and hydroxypropylcellusose as a gelling agent. In vitro percutaneous absorption studies were performed to determine the rate of $PGE_1$ absorption through rat or hairless mouse skin. The permeability of $PGE_1-EE$ lyogel with enhancer was 16-fold greater than that of lyogel without enhancer. Cosolvent produced 9-fold increase in percutaneous absorption. Pharmacodynamic effects of lyogels were evaluated in mature male cats in terms of intracavernosal pressure (ICP). Lyogels containing 0.1 % of $PGE_1-EE$ showed higher ICP compared to intraurethral preparation of $PGE_1$ (1 %) and enhancer-free control lyogel. The shelf-life $(t_{10%})$ of lyogel at refrigerated condition $(4^{\circ}C)$ was calculated as 928 days, which is 4.2 times longer than that of control hydrogel. As a result, $PGE_1-EE$ was formulated successfully to a lyogel system with a selective enhancer and cosolvent system for the topical delivery of $PGE_1$.