• Asian-Australasian Journal of Animal Sciences
• /
• v.6 no.2
• /
• pp.281-290
• /
• 1993

This experiment was designed to evaluate the effect of degree of unsaturation (Experiment 1) and the chain length of constituent fatty acids of dietary fats (Experiment 2) on-3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activities in the liver and small intestine of chicks. Chicks were fed experimental diets for 10 days and then killed for the determination of the HMG-CoA reductase activities in the intestinal epithelial cell and hepatic microsomes. The hepatic HMG-CoA reductase activity showed the highest value in chicks fed the tallow-containing diet. Chicks fed diets containing safflower or coconut oil resulted in a significantly lower intestinal HMG-CoA reductase activity in comparison with those fed the olive oil-containing diet. The hepatic HMG-CoA reductase activity was significantly higher when fat-free and trilaurin were fed than when any other triglycerides were fed. This activity showed the lowest value in the chicks fed the diet containing tristearin. The HMG-CoA reductase activities in the jejunum and ileum were significantly or tended to be higher when trilaurin was fed than when any other triglycerides were fed. Except when trilaurin was fed, the presence of saturated fat in the diet did not have a significant effect on the intestinal HMG-CoA reductase activity, unlike the effect shown when a highly unsaturated fat was added to the diet. There was no significant correlation between the HMG-CoA reductase activities of the liver and intestinal, and the HMG-CoA reductase activity and cholesterol content of the intestinal epithelial cells.

• Journal of Pharmaceutical Investigation
• /
• v.40 no.1
• /
• pp.39-43
• /
• 2010

Solid lipid nanoparticles (SLNs) were freeze-dried to obtain a stable solid dosage form with the aid of various cryoprotectants such as trehalose, sucrose, glucose, fructose, and glycerol. Tricaprin(TC) and trilaurin(TL) were used as lipid matrices for SLNs and stabilizers were egg phosphatidylcholine and pegylated phospholipid. All cryoprotectants tested did not cause changes in mean particle size of SLNs when mixed with SLNs before freeze-drying. However, the mean particle sizes of reconstituted SLNs after freeze-drying were significantly different from those of the un-lyophilized original SLN dispersions depending on the types and concentration of cryoprotectants. Although the freeze-dried SLNs without any cryoprotectants were easily reconstituted by hand-shaking, the mean particle size drastically increased (> $8\;{\mu}m$ for TC SLNs and around $1\;{\mu}m$ for TL SLNs) compared to that of un-lyophilized original dispersion (97 nm for TC SLNs and 164 nm for TL SLNs). Trehalose and sucrose were the most effective additives to protect the SLNs during lyophilization. The reconstituted SLNs were physically stable for 24 hours when lyophilized with 12.5% trehalose, sucrose, glucose, fructose or glycerol.

• Journal of Pharmaceutical Investigation
• /
• v.26 no.2
• /
• pp.125-135
• /
• 1996

Solid lipid nanoparticles(SLN) are particulate systems for parenteral drug administration and suitable for controlled release. SLN were prepared by homogenization process. Dispersion at increased temperature (molten lipid) was performed to yield SLN loaded with lipophilic drugs. Tetracaine base, lidocaine base, prednisolone, methyltestosterone and ethinylestradiol were used as model drugs to access the loading capacity and to study the release behavior. To investigate production parameters(lipids, surfactant concentration, homogenizing rpm) in the formation of SLN, particle size was performed by laser diffraction analysis. The mean particle size of SLN with stearic acid or trilaurin was below 1 micron. By decreasing the particle size and increasing the surfactant concentration, the release rate was increased especially in the case of highly lipophilic drug loaded SLN. Methyltestosterone or ethinylestradiol loaded SLN showed a distinctly prolonged release over a few days.

• Journal of Pharmaceutical Investigation
• /
• v.26 no.4
• /
• pp.245-256
• /
• 1996

Solid lipid nanoparticles (SLN) have been developed as a new drug delivery system. Although many particulate drug carriers, such as microsphere, liposome, niosome, emulsion, etc. have been introduced, they have some disadvantage; low efficiency of incorporation and stability, lack of reproducibility, and so on. Meanwhile, SLN as a new drug delivery system is known to entrap rugs with a high efficiency and a good reproducibility. Moreover, small size SLN can circulate in blood for a prolonged time. Although many preparation methods were introduced, microfluidization method is recommended to be the most useful. This study was attempted to prepare and evaluate ketoprofen-incorporated SLNs (keto-SLN), which were prepared by two methods, ultrasonication and microfluidization. Keto-SLN was evaluated by measurement of particle size and zeta potential, efficacy of entrapment, sedimentation volume, in virto release pattern. The mean particle size was about $0.1\;{\mu}m$, and the size was dependent on the type and the amount of emulsifier. Zeta potential was negative, $-9{\sim}-13mV$ and entrapment efficacy was very high and stability was good for at least 60 days in the respect of particle size and sedimentation volume ratio. Analgesic effect was also determined as well as pharmacokinetic parameters. The former was comparable to that of that of ketoprofen loaded suspension (keto-sus) and the latter revealed that consistent with the delayed release of keto-SLN. $T_{max}$ was longer than keto-sus. Therefore, keto-SLN was favourable dosage forms in the field of drug delivery system such as anti-cancer, analgesics and anti-inflammatory agents.