| Summary: | 碩士 === 高雄醫學大學 === 藥學研究所 === 82 === The fluoroquinolones represent an important advance in antimicrobial therapy. They differ significantly in their antimicrobial spectrum of activity and their pharmacokinetic characteristics. In our series studies about quinolone percutaneous aborption properties, enoxacin presented the best permeability characteristics in six quinolones. Therefore, We took a further transdermal research for enoxacin in this experiment.
Enoxacin is an amphillic compound (pka1=6.4, pka2=8.4) , its solubility is affected by pH values of vehicle notably. It is more soluble in acidic or basic solution, but there is a higher partition coefficient in neutral state. The permeation rate of enoxacin is also influenced by the variation in buffer pH values, it is high in pH=3 buffer and low in pH=8 buffer. The flux of enoxacin is enhanced four times through stripped skin than intact skin.
Cationic surfactant (benzalkonium chloride) presented the best enhancing effect no matter what the buffer pH values are. The enhancing factor reached 300 in pH3 BC 1%(w/v) sol'n. Besides, it results in the shorter lag time when benzalkonium chloride is used. In sodium lauryl sulfate solution, enoxacin displayed a different penetration profile with a longer lag time. Flux was decreased in the acidic state and increased in basic state Nonionic surfactants (Tween 80) didn't show any enhancing effect on the percutaneous absorption of enoxacin markly. And the flux was decreased to 1/3 at pH 10 condition.
Increase in β-cyclodextrin (CD) concentrations wo'nt raise the the solubility of enoxacin. There were three kind of melliods to prepare inclusion complex and the products were evaluated by differential scanning calorimetry and IR spectrum. There were no sign to show the inclusion complex formed. It's difficult for enoxacin to form an inclusion complex with β-CD. The permeation properties of enoxacin is not changed by adding α-CD, β-CD, or γ-CD into donor solutin.
EDTA is a kind of chelating agent. Its effects on increasing enoxacin solubility and permeability are EDTA concentration dependent in purified water but altered by buffer system in buffer solution.
The results of in vitro enoxacin percutaneous absorption study offered a foundaion of enoxacin transdermal delivery system. In order to get a better therapeutic efficacy and convenience for skin and soft tissue infections.
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