• Journal of Pharmaceutical Investigation
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• v.32 no.2
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• pp.73-80
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• 2002

Cefuroxime axetil is a cephalosporin antibiotic having a high activity against a wide spectrum of Grampositive and Gram-negative microorganisms. It is a cephalosporin antibiotic which exist as 2 diastereoisomers: diastereoisomer A and B. It shows polymorphism of three forms: a crystalline form having a melting point of about $180^{\circ}C$, a substantially amorphous form having a high melting point of about $135^{\circ}C$ and a substantially amorphous form having a low melting point of about 70^{\circ}C$. The crystalline form of cefuroxime axetil is slightly soluble in water because diastereoisomer A has lower solubility than B in water. Substantially amorphous form of which there are no difference in solubility between diastereoisomer A and B has better solubility than crystalline form, but it forms a thicker gel than crystalline form upon contact with an aqueous medium. Based on this reason, cefuroxime axetil is not readily absorbable in the gastrointestinal tract, rendering its bioavailability on oral administration very low. The object of this study was to develop an improved non-crystalline cefuroxime axetil composition having a high physicochemical stability and bioavailability. A non-crystalline cefuroxime axetil solid dispersant showing no peak on a Differential Scanning Calorimetry (DSC) scan is prepared by dissolving cefuroxime axetil and a surfactant in an organic solvent; suspending a water-insoluble inorganic carrier in the resulting solution; and spray drying the resulting suspension to remove the organic solvent, said solid dispersant having an enhanced dissolution and stability of cefuroxime axetil and being useful for the preparation of a pharmaceutical composition for oral administration. Tablet was formulated with this cefuroxime axetil solid dispersant, disintegrants and other ingredients. It disintegrated and dissolved easily and dynamically in dissolution medium, so showed a good dissolution profile.

• Journal of the Korean Chemical Society
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• v.46 no.4
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• pp.393-397
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• 2002

• Bulletin of the Korean Chemical Society
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• v.22 no.11
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• pp.1236-1242
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• 2001

(3S,1'S)-3-(1'-Carboxy-2'-phenyl)ethylamino-2-oxetanone (1a) and (3R,1'S)-3-(1'-carboxy-2'-phenyl)ethylamino-2-oxetanone (1b) were designed, synthesized, and evaluated as inhibitors for carboxypeptidase A, a prototypical zinc protease that removes the C-terminal amino acid having an aromatic side chain from oligopeptide substrate. It was concluded from the analysis of inhibition kinetics that while 1a inactivates CPA irreversibly, its diastereoisomer, 1b is a weak competitive inhibitor for CPA. A possible explanation for the observed difference in inhibition mode that is dependent on the inhibitor stereochemistry is offered.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.2
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• pp.151-158
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• 2009

We found that silymarin exhibited the inhibitory effect on melanogenesis in a spontaneously immortalized mouse melanocyte cell line, Mel-Ab. Silymarin is a standardized extract obtained from the dried seeds of milk thistle (Silybum marianum Gaertn.). Silymarin significantly prevented melanin production in a dose-dependent manner with an $IC_{50}$ value of 28.2 ${\mu}g/mL$ without effects on cell viability. Also, silymarin inhibited tyrosinase activity in melanocyte, while it did not affect the catalytic activity of cell-free tyrosinase. Furthermore, Western blot analysis indicated that silymarin decreased the expression of tyrosinase protein. Silybin A/B and isosilybin A/B were also able to inhibit melanin production and tyrosinase expression in protein level. Double blind study on the clinical efficacy of a cream containing 2 % silymarin showed that silymarin have a significant skin whitening effect. Therefore, this study suggests that silymarin may be useful as a natural skin whitening agent.