- Novel skin permeation enhancers based on amino acid ester ionic liquid: Design and permeation mechanism
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This study developed novel ionic liquids (ILs) based on amino acids. We first screened 15 methyl amino acid ester hydrochlorides ([AAC1]Cl) for their skin permeation enhancements using 5-Fluorouracil (5-Fu) and Hydrocortisone (HC) as model drugs. Glycine methyl ester hydrochloride ([GlyC1]Cl), L-proline methyl ester hydrochloride ([L-ProC1]Cl), and L-leucine methyl ester hydrochloride ([L-LeuC1]Cl) were selected, and their ester sites were modified with different carbon chains (C8 and C12). The resulting ILs showed improved permeation to the two drugs. TEWL and CLSM assays revealed the moderation effects of the modified ILs on skin barrier function, whereas L-proline dodecyl ester hydrochloride ([ProC12]Cl) and L-leucine dodecyl ester hydrochloride ([L-LeuC12]Cl) exhibited the strongest activities. Permeation mechanisms were further investigated by ATR-FTIR, solid-NMR, SEM, and TEM analyses. The results suggested that [L-ProC12]Cl and [L-LeuC12]Cl combined the advantages of amino acid esters and IL solvent and could interact with the intercellular lipid domain by the multi-functions of lipid fluidization and lipid extraction, which were observed in a dosage- and time-dependent manner. Additionally, pathological examination suggested that the amino acid ester-based ILs (AAE-ILs) had good biocompatibility. In conclusion, this study has generated novel chemical penetration enhancers (CPEs) based on AAE-ILs and may be potentially utilized in drug transdermal delivery systems (TDDSs).
- Li, Yaming,Wang, Chengxiao,Yang, Ye,Zhao, Zhiyuan,Zheng, Luyao
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- Amino acid ester hydrochloride and preparation method and application thereof
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The invention discloses amino acid ester hydrochloride and a preparation method and application thereof. The preparation method comprises the following steps: adding amino acid, alcohol and p-toluenesulfonic acid into toluene, carrying out reflux reaction for 4 h at the temperature of 130-140 DEG C, extracting a reaction solution for three times by using a NaOH solution with the mass percent concentration of 5%, drying an organic layer overnight by using anhydrous sodium sulfate, removing a solvent by evaporation, and carrying out column chromatography by taking a mixed solution obtained by mixing petroleum ether with isopropanol according to the volume ratio of 5-6: 1 as an eluent to obtain colorless liquid amino acid ester; and introducing dry hydrogen chloride gas into the amino acid ester for 1-1.5 h to obtain the amino acid ester hydrochloride. The amino acid ester hydrochloride serving as a penetration enhancer has a good using effect in a transdermal drug delivery system, the amino acid ester hydrochloride promotes transdermal absorption of drug, so that the fluidity of keratinocytes is enhanced, and the transdermal amount of the drug is effectively increased. By the drug transdermal penetrant, the solubility of drug is improved effectively, the absorption rate of the drug is increased, the treatment effect is improved, and the application prospect is wide.
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Paragraph 0018-0020
(2019/10/17)
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- Synthetic ceramide analogues as skin permeation enhancers: Structure-Activity relationships
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The study presents new information about the structure-activity relationships of the skin permeation enhancers. A series of ceramide analogues including eight different polar head groups and six different chain lengths was synthesised. The compounds were evaluated as permeation enhancers in vitro using porcine skin. The physico-chemical parameters of the tested compounds obtained by computer modelling were used to evaluate, by multiple linear regression, the enhancement ratios (ERs) of the compounds. The regression analysis suggests that the hydrogen bonding ability of the compounds is inversely related to the ER values and that the molecular size and lipophilicity must be well balanced. In the studied enhancers having the same chain length, the enhancement activity is dependent only on their permeability coefficients. This finding confirms the Warner's hypothesis that the polar head of an enhancer is responsible for the permeation and anchoring of the molecule into the stratum corneum lipids and that it does not influence the mechanism of action. For the specific action of enhancers, that is disordering of the intercellular lipid packing, the length of the hydrophobic chain(s) and not the lipophilicity is important. Furthermore, the examination of the FTIR spectra indicated that the most active substances possess the most ordered chains. The described relationships could bring more rational approaches in designing new potent enhancers for transdermal formulations.
- Vavrova, Katerina,Hrabalek, Alexandr,Dolezal, Pavel,Samalova, Lucie,Palat, Karel,Zbytovska, Jarmila,Holas, Tomas,Klimentova, Jana
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p. 5381 - 5390
(2007/10/03)
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