• Proceedings of the PSK Conference
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• 2000.10a
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• pp.262.1-262.1
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• 2000

• YAKHAK HOEJI
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• v.42 no.3
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• pp.265-274
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• 1998

In order to attain a sustained release at targeted organs in a prolonged time which can reduce the side effects and maximize the therapeutic effect, aclarubicin (ACL) was entrap ped into liposomes of different lipid compositions using Microfluidizer, and dry liposomes were prepared by lyophilization. The dry aclarubicin-entrapped liposomes were evaluated in terms of mean particle size and size distribution, entrapment efficiency and in vitro drug release profile. The Entrapment efficiency of liposome, when the concentration of aclarubicin and lipid were 0.5 to 1.0mg/ml and $200{\mu}mol$/ml, respectively, was over 80% using Microfluidizer, in contrast to 70% of entrapment efficiency using hand-shaking method. Mean particle size and size distribution of aclarubicin-entrapped liposomes of various lipid compositions did not change considerably by the freeze drying. The range of particle size was between 80 and 200nm. Among aclarubicin-entrapped liposomes, ACL-liposome of PC/DPPC/CH0L/TA displayed the most significant sustained release. The addition of DPPC appeared to be favorable for the control of release. In general, aclarubicin entrapped in liposomes was less stable than free aclarubicin either in pH 7.4 phosphate buffer or in human plasma. Formulation I($t_{1/2}$, 20.3 hr) devoid of lipid additive was the most unstable in the phosphate-buffer solution while formulation II($t_{1/2}$, 40.7 hr) with cardiolipin was the most stable. Half lives of aclarubicin-entrapped liposomes in human plasma were 43.2, 50.7, 35.9 and 35.3 hr for formulation I. II, III and IV, respectively, in contrast to 57.8 hr for free aclarubicin.

• KSBB Journal
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• v.23 no.5
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• pp.408-412
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• 2008

The rosiglitazone loaded poly (lactide-co-glycolide) (PLGA) nanoparticles (NPs) were prepared by the emulsion-evaporation method and optimized for particle size and entrapment efficiency. The optimized particles were 140-180 nm in size with narrow size distribution and 80% entrapment efficiency at 1% w/w initial drug loading when prepared with 1-3% w/v of PVA as a surfactant. These particulate carriers exhibited controlled in vitro release of rosiglitazone for 36 hrs at a nearly constant rate after 4 hrs release. In conclusion, these results indicate that PLGA NPs have greater potential for oral delivery of rosiglitazone.

• Advances in Traditional Medicine
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• v.8 no.2
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• pp.178-186
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• 2008

In this study, ionotropic gelation method was used for the preparation of ibuprofen-loaded calcium alginate (CALG) and ethylenediamine (EDA) treated calcium alginate (EDA-CALG) microspheres. The effect of EDA-treatment on drug entrapment efficiency, particle size, morphology, swelling behavior and in vitro release characteristics of the microspheres was investigated by varying its concentration from 0.5 to 2% (v/v). The reduction in drug entrapment efficiency by a maximum of 44.60% was noted for EDA-CALG microspheres compared to untreated CALG microspheres. The particle size and swelling index of EDA-CALG microspheres were reduced with increasing EDA concentration. All the microspheres were observed to retain their spherical shapes with rough surfaces. EDA-CALG microspheres prepared using 1% and 2% v/v EDA, released almost all of its content within 7 h in pH 6.8 phosphate buffer, however, CALG microspheres were found to release the same within 3 h. The intensity of melting endothermic peak of ibuprofen reduced significantly at lower drug load as experienced from DSC thermograms. The FT-IR spectrum of pure ibuprofen, ibuprofen-loaded CALG and EDA-CALG microspheres showed the characteristic band of C = O stretching vibration of ibuprofen. Hence, this study revealed that EDA can be employed for the preparation of ibuprofen-loaded CALG microspheres to retard the drug release to some extent.

• Journal of Pharmaceutical Investigation
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• v.35 no.3
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• pp.143-150
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• 2005

Solid lipid nanoparticles(SLNs) are particulate systems for parenteral drug administration and have good biocompatibility and stability. SLNs were prepared with lauric acid, as the lipid core. Tween 20 and tween 80 were used as surfactant. 5-fluorouracil and l-benzoyl-5-fluorouracil were used as model drugs. Drug-loaded SLNs were prepared by the hot homogenization technique in order to evaluate the physical stability, entrapment efficiency of drugs as well as release profile. The particle size of SLNs was $40{\sim}600$ nm. By increasing speed, the mean particle size of SLNs was decreased. And entrapment efficiency in the case of using 1-Benzoyl-5-fluorouracil was higher than using 5-Fluorouracil. The higher surfactant concentration, the faster release rate at the range of $1.5{\sim}2.5%$.

• Journal of Pharmaceutical Investigation
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• v.31 no.4
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• pp.257-263
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• 2001

The microspheres have been developed as a new drug delivery system. Although many particulate drug carriers, such as liposome, niosome and emulsion, have been introduced, injectable and biodegradable microspheres appears to be a particularly ideal delivery system because the local anesthesia is not necessary for the insertion of large implants and for the removal of the device after the drug release is finished. Biodegradable microspheres with nicotine and triamcinolone acetonide are prepared and evaluated. As biodegradible polymers, PLA (M.W. 15,000, PLA-0015), PLGA (M.W. 17,000, RG 502) and PLGA (M.W. 8,600, RG 502H) are used. This study attempted to prepare and evaluate the nicotine and triamcinolone acetonide-incorporated microspheres, which were prepared by two methods, solvent-evaporation and spray-drying methods. The microspheres, as a disperse system for injections, were evaluated by particle size, size distribution, entrapment efficiency, and in vitro drug release patterns. The differences of preparation method, partition coefficient, types of polymer, and preparation conditions of microspheres influence the particle size, entrapment efficiency, and in vitro drug release patterns.

• YAKHAK HOEJI
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• v.47 no.2
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• pp.78-84
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• 2003

Local anesthetics are used to reduce pain, but they are so frequently injected to patients. So, we prepared lidocaine solid lipid microspheres (SLM) as long acting abdominal injection using spray drying method and evaluated drug entrapment, particle size, SEM, zeta potential and in vitro and in vivo drug release pattern, The particle sizes of SLM were 30∼100$\mu$m and it is enough to inject into abdominal tissue. The entrapment efficiency of SLM was over 95％ as spray drying method. Surfactant and PC decreased the burst effect by 20∼30％. In in vivo test, C-6 showed controlled release concentration profile in plasma for 8 days and C-5 sustained longer than we expected.

• Applied Chemistry for Engineering
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• v.26 no.5
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• pp.563-568
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• 2015

Liquiritin and its aglycone, liquiritigenin are flavonoid found in licorice that show anti-oxidant and anti-aging properties. In this study, ethosomes loaded with hydrophobic liquiritigenin or liquiritin were prepared as a transdermal delivery system. The particle size, entrapment efficiency, and skin permeability of ethosomes were evaluated. Ethosome containing liquiritigenin was stable up to 2 mM and ethosome containing liquiritin was stable up to 0.75 mM concentration. The particle size of ethosomes containing 0.75 mM liquiritigenin and liquiritin was 143.85 and 158.90 nm, respectively and the entrapment efficiency was 47.51 and 54.61%, respectively. The entrapment efficiency was improved with increasing concentrations of drugs. Ethosomes loaded with liquiritigenin or liquiritin were superior in skin permeation ability compared to that of 20% ethanol solution and conventional liposomes. These results suggest that ethosomes containing 0.50 mM liquiritigenin or liquiritin are effective for the skin permeation and may be used as an antiaging and antioxidant ingredient in cosmetic formulation.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.247.2-247.2
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• 2003

To increase skin permeability of LMWH (Low Molecular Weight Heparin), ultradeformable liposomes were developed. Ultradeformable liposomes were developed by Egg phosphatidylcholine (Egg-PC) and edge activator. Entrapment efficiency, vesicle size and zeta potential of vesicles were determined and characterized for deformability and stability. Transepidermal permeation of LMWH was compared to saturated aqueous control in vitro. The steady-state flux and its maximum time were calculated from the flux curves. (omitted)

• Archives of Pharmacal Research
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• v.29 no.9
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• pp.795-799
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• 2006

Peptides, although high efficacy and specificity in their physiological function, usually have low therapeutical activities due to their poor bioavailability when administrated orally. Nanoparticles have been regarded as a useful vector for targeted drug delivery system because they can protect drug from being degraded quickly and pass the gastrointestinal barriers. Here we described a novel oral N-trimethyl chitosan nanoparticles formulation containing thymopentin (Tp5-TMC-NP). N-trimethyl chitosan (TMC) was synthesized and then used to prepare Tp5-TMC-NP by ionotropic gelation. A three-factor, five-level CCD (Central Composite Design) design was used in the optimization procedure, with HPLC as the analyzing method. The resulting Tp5-TMC-NP had a regular spherical surface and a narrow particle size range with a mean diameter of 110.6 nm. The average entrapment efficiency was 78.8%. The lyophilized Tp5-TMC-NP formulation was stable in $4^{\circ}C\;or\;-20^{\circ}C$ after storage of 3 months without obvious changes in morphology, particle size, pH and entrapment ratio. The results of the flow cytometer determination showed that the ratio of $CD4^+/CD8^+$ of Wistar female rat given Tp5-TMC-NP (ig) was 2.59 time that of the group given Tp5 (ig).