• Journal of Pharmaceutical Investigation
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• v.30 no.2
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• pp.119-125
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• 2000

In an attempt to develop a non-aqueous liquid formulation of practically insoluble biphenyl dimethyl dicarboxylate (DDB), dissolution and permeation studies were performed. Various non-aqueous DDB solutions were formulated and filled into empty hard capsules. Dissolution rates of a new formulation were compared with those of commercially available DDB preparations using one and eight dose units. Dissolution rates after 2 hr of DDB tablets (DDB 25 mg), hard capsules (DDB 7.5 mg) and soft capsules (DDB 7.5 mg) on market and new formulation (DDB 7.5 mg) were 6.3, 15.0, 84.5 and 98.0%, respectively. Higher doses (8 units) resulted in a supersaturation within one hr of dissolution, and dissolved amounts were reduced markedly. Due to the saturation and precipitation, a directly proportional dose-dissolution relationship was not observed. The addition of copolyvidone and/or glycyrrhizic acid ammonium salt to DDB solution in polyethylene glycol 300 and 400 inhibited the formation of precipitates during dissolution and markedly enhanced the rabbit duodenal permeation of DDB. From the site-specific gastrointestinal permeation studies, it was found that permeation rates of DDB after mixing of non-aqueous DDB solutions with aqueous buffered solutions were faster in the order of $rectal\;<\;colonic\;{\risingdotseq}\;ileal\;{\risingdotseq}\;duodenal\;<\;jejunal\;<\;gastric$.

• Journal of Pharmaceutical Investigation
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• v.31 no.1
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• pp.27-35
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• 2001

To evaluate the site-specific permeation of aspalatone (acetylsalicylic acid maltol ester, AM) through gastrointestinal tract, the enzymatic degradation and permeation studies were carried out using gastric, duodenal and jejunal mucosae of rabbits. It was found that $15.2{\pm}11.4%$, $11.6{\pm}5.2$ and $0.8{\pm}0.6%$ of the donor dose of AM, salicylmaltol (SM) and aspirin (ASA) permeated through the upper gastric mucosa after 8 hr of permeation, respectively. After 8 hr of AM permeation, SM and ASA were measured to be $15.0{\pm}1.7$ and $2.6{\pm}0.8%$ of the dose in the donor solutions, respectively, and salicylic acid (SA) was not detected even after 6 hr, suggesting a very low gastric damage. For the gastric mucosa, the increase of donor dose from 100 to $1,000\;{\mu}g/ml$ increased the permeation flux dose-dependently (r=0.9905). For the duodenal and jejunal mucosae, however, AM was fully degraded into SM and SA due to the esterase activities within 30 min. AM and ASA were not detected in the receptor solution. This result indicates that AM is not a prodrug of ASA. Addition of potassium fluoride (0.5%) into the donor solution delayed the degradation of AM, but did not allow the permeation through duodenal mucosa even by the inhibition of esterase activity. The addition of $dimethyl-{\beta}-cyclodextrin$ and $2-hydroxypropyl-{\beta}-cyclodextrin$ (5%) into the donor solutions also did not show favorable effects on the permeation of AM through various mucosae. In comparison of permeation rates of AM and ASA through the upper gastric mucosa, the flux of ASA was 4.2 times faster than AM based on the molar concentration. ASA also was fully degraded in the donor solutions faced with duodenal and jejunal mucosae within 2 hr, and was not detected in the receptor solution, suggesting a slower metabolism compared with AM.

• Journal of Pharmaceutical Investigation
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• v.32 no.4
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• pp.291-297
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• 2002

For preventing and curing the stretching mark, TECA Niosome/W/O system creams were formulated using Titrated Extract of Centella Asiatica (TECA) which is well known for its excellent wound healing effect. The lipid-water partition coefficients and the stabilities of TECA were evaluated and TECA Niosome/W/O system (TECA N/W/O) creams were prepared with different concentrations of cetyl alcohol and ceramide. TECA N/W/O cream was evaluated with respect to their rheological properties, permeation through excised skin of hairless mouse and in vitro and in vivo accumulation in the skin of hairless mouse. In addition, dermal thicknesses of hairless mouse skins were determined following the in vivo application of TECA N/W/O cream and control cream. TECA N/W/O creams showed pseudoplastic flow and hysteresis loop. The permeation of TECA from formulations through excised skin of hairless mouse did not observed. Amount of accumulated drug in the excised skin of hairless mouse was deσeased with an increase in the concentration of cetyl alcohol and showed no relationship with concentration of ceramide. Amount of accumulated drug in formulation A-3 was higher than in niosome suspension and other formulations. In in vivo experiment, amount of accumulated drug in formulation A-2 and A-3 was much higher than that of niosome suspension. Being treated with the N/W/O cream for 8 weeks, the dermal thickness of hairless mouse skin was increased 3.2 times than that of 16 weeks-control group.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.567-572
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• 2010

5,10-Methenyltetrahydrofolate synthetase from chicken liver was purified through 30-70% ammonium sulfate fractionation, Q Sepharose Fast Flow anion exchange and Source 15Phe hydrophobic interaction chromatography. Specific activities of cell extract, ammonium sulfate, Q Sepharose Fast Flow and Source 15Phe were 0.0085, 0.031, 0.80 and 1.27 U/mg, respectively. Purification fold activities of cell extract, ammonium sulfate, Q Sepharose Fast Flow and Source 15Phe were 1, 3.7, 94.1 and 149.4, respectively. HPLC gel permeation chromatography and SDS-polyacrylamide electrophoresis experiments indicated that the enzyme is a monomeric protein with a molecular weight of 22.8 kDa. Km for 5-methyl THF and Mg-ATP were $7.1\;{\mu}M$ and $63\;{\mu}M$, respectively. Optimum temperature and pH were $30^{\circ}C$ and 6.0, respectively. The data for metal ion specificity and stoichiometry showed that the maximum activity was obtained with a 1:l. ratio of $Mg^{2+}$. The ATP and Km values increased in the order of MgATP, MgCTP, MgUTP and MgGTP, and the maximum activities also decreased in the same order, indicating MgATP as the most efficient substrate. The enzyme was chemically modified only by tetranitrometane and 1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide, indicating that tyrosine and carboxylate are present in the active site.

• Parasites, Hosts and Diseases
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• v.27 no.3
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• pp.161-170
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• 1989

The proteases of Toxoplasma gcndii were purified partially and characterisrd for some biochemical properties including various chromatographic patterns, major catalytic classes, and conditions to promote the activity of these enzymes. When Toxoplasma extract was incubated with 3H-casein at various pH, peak hydrolysis of casein was observed at pH 6.0 and at pH 8.5. Proteasfs working at pH 6.0 and at pH 8.5 were purified partially by conventional methods of chromatographies of DE52 anion rxchange, Sephadex G-200 gel permeation, and hydroxylapatite chromatography. Partially purified enzymes were tested by site-specific inhibitors and promotorf. The protease working at pH 6.0 was inactivated by iodoacetamide with LDso of 10-5 M and promoted by dithiothreitol, while the protease working at pH 8.5 was inhibited by phenylmethylsulfonyl fluoride with LD50 of 10-5 M and was Promoted by ATP (excess ATP beyond 2 mM inhibited the activity reversely). The protease of pH 8.5 had the activity of ATPase which might exert the energy to its action. Therefore the former was referred to as a cysteinyl acid protease and the latter, ATP-dependent neutral serine protease.