关键词: 尿素维E乳膏, 抑菌剂, 抑菌效力, 羟苯乙酯

Abstract:

Objective： To evaluate the amount and efficacy of preservatives added in urea and vitamin E cream from different manufacturers.Methods： High-performance liquid chromatography （HPLC） was used to determine the preservatives in urea and vitamin E cream. The chromatographic column was Capcell PAK C18 （250 mm × 4.6 mm， 5 μm）， the mobile phase was methanol-1% glacial acetic acid （60∶40）， the flow rate was 1 mL·min^-1， the detection wavelength was 254 nm， and the injection volume was 10 μL. The antimicrobial efficacy test was conducted according to the "Pharmacopoeia of the People's Republic of China". Staphylococcus aureus， Pseudomonas aeruginosa， Escherichia coli， Candida albicans， and Aspergillus niger suspensions were prepared and added to samples from 10 manufacturers， with the bacterial content of the samples being approximately 10⁵ ~ 10⁶ cfu·g⁻¹. After mixing， the samples were stored in the dark at 20 ~ 25 ℃. The viable bacterial counts were measured at four time points： 2， 7， 14， 28 d.Results： The linear ranges for methylparaben， ethylparaben， and butylparaben were 0.01 ~ 0.1 mg·mL^-1， respectively. The relative standard deviation （RSD） for precision， repeatability， and stability is all less than 1%. In the samples from 9 manufacturers， ethylparaben was used as the preservative， with concentrations ranging from 0.05% to 0.20%. In the sample from 1 manufacturer， methylparaben and butylparaben were used as preservatives， with concentrations of 0.1% and 0.05%， respectively. In the antimicrobial efficacy test， the logarithmic reduction of bacterial counts after 2 d was greater than 2， and after 7 d it was greater than 3； no increase in bacterial counts was observed over 28 d. For fungi， a logarithmic reduction greater than 2 or equal to in colony counts was observed after 14 d， with no increase in counts over 28 d. The antimicrobial efficacy of products from all manufacturers met the requirements.Conclusion： The antibacterial efficacy of the urea and vitamin E cream preparation is good， with a significant variation in the amount of antibacterial agent added.

Key words: Urea and vitamin E cream； , Preservatives； , Antimicrobial efficacy； , Ethylparaben