• Journal of Pharmaceutical Investigation
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• v.28 no.1
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• pp.51-57
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• 1998

Tetracycline lyogel ointment consisting of hydroxy ethyl cellulose(HEC) in glycerin and Eudragit RS 100 in triacetin were prepared and then release characteristic were investigated. The physical properties of lyogel ointment such as viscosity, particle size and microscopic structures were also evaluated. The microscopic structures showed that lyogel particles containing drug were dispersed in the triactin solution. The release rate of drug from lyogel ointment as a function of HEC was not changed. However the release rate was significantly decresed when the amount of Eudragit RS 100 and triacetin in lyogel ointment was increased. The viscosity and weight fraction in external phase of lyogel ointment influenced the release rate. The current studies suggest that the release rate of drug can be controlled by changing of lyogel ointment compositions.

• YAKHAK HOEJI
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• v.60 no.1
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• pp.46-50
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• 2016

The purpose of this study was the development of sustained-release lyogel of chlorhexidine in the treatment of periodontal diseases. A sustained-release chlorhexidine lyogel (CHX-G) was formulated, based on Eudragit$^{(R)}$ (1~3%), polyvinyl pyrrolidone (PVP) (0~10%), triacetin (20~40%), hydroxy ethyl cellulose (HEC) (1%) and glycerin. In vitro studies were performed to determine the release rate of chlorhexidine from CHX-Gs using dialysis tube. Our results suggest that the release rate of chlorhexidine from lyogel could be controlled by changing the lyogel compositions.

• Journal of Pharmaceutical Investigation
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• v.34 no.2
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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 $PGE_1$.