| Hyaluronic acid(HA), a nonbranched polysaccharide. is composed of regularly alternating units of D-giueuronic acid and N-acetyl glueosamine linked by β-(1â†'3) and β-(1â†'4) glycosidic bonds. The weight average molecular weight range of natural HA is within1×105～107D and the molar ratio of the two monosaccharides in the molecular structure is1:1. HA is generally prepared by extraction from animal tissues or by bacteria fermentation.Because HA has a good moisturizing effect, nutrition, skin damage repair and preventive effect, thickening, etc., its application in the field of cosmetics are increasingly widespread. HA general merchandise to its sodium salt, ie sodium hyaluronate.This topic focuses on the cosmetic use of sodium hyaluronate physical and chemical, microbiological quality standards and related test methods.1.Appearance SH visually observed for the test should be white or white granules or powder.2. Identification1) SH samples for test pieces of the infrared absorption spectrum (4000cm-1～400cm-1) should be controlled with the SH infrared absorption spectrum (<<IR set>> Volume IV1173figure) consistent, That is, near3400cm-1.1610cm-1,1400cm-1,1040cm-1is present the characteristic absorption.2) Sodium hyaluronate sodium flame test solution for differential response, in a colorless flame burning bright yellow should be significantly.3. pH6.0to8.0. Measured with a pH meter for the test solution1mg/ml in SH, the pH should be6.0to8.0.4.1ight transmittance of the solution (0.5%, A550nm)>99.0%The purified water as a blank, measured at a wavelength of550nm light transmittance5mg/mISH solution should be≥99.0%. S.loss on dryingIn this study, five batches of SH samples measured by oven drying loss on drying is:6.40,6.44,6.35,6.23.6.30; heated drying under reduced pressure measured as:6.38,6.43,6.30,6.17,6.22; Halogen Moisture Analyzer Measurement was as follows:6.42,6.48,6.31,6.19,6.26. The results of three methods are basically the same, but the first two methods required for a long time, with a halogen moisture analyzer at110℃,15minutes to complete the determination of loss on drying.6. average relative molecular weight.In this study, samples of five batches SH measured by multi-point intrinsic viscosity [η], respectively:27.32,24.64,22.56,16.18,13.42;point determined by [η] were:27.54,22.57,23.62,16.85,14.27. Point method with multi-point method measured the SH [η] is very close, in ensuring Ti and TO are greater than100s, and T1/To=1.30～1.50, can be used instead of multi-point method determination of SH [η]. Then calculated by the equation SH average relative molecular weight.7. sodium hyaluronate content (on dry basis)≥92.0%In this study. Bitter and Muir modified carbazole determination SH sample glucuronic acid content, multiply by2.0675, that is, too. And make a determination method validation.Accuracy test:reference standard addition method, the average recovery was98.7%(recovery of98.0～102.0%should) meet certification requirements.Precision test:6copies of repeated measurements using the test content and the relative standard deviation expressed as relative standard deviation of measurement results was1.15%, in line with the relative standard deviation of not more than2.0%of the validation requirements.Linearity and range test:This method is applicable range of glucuronic acid concentration of0～50μg/ml:within this range, glucuronic acid concentration and absorbance calculate the regression equation, correlation coefficient of0.9998. in line with the correlation coefficient of not less than0.990requirements.Durability test:This study investigated the reaction time on the determination results. After testing, the hydrolysis step is more than8minutes after the heating time constant measurement results, in order to ensure the hydrolysis reaction, the hydrolysis step finalize heated for10minutes; step chromogenic reaction water bath for15minutes, the test should be strictly control.Specificity:This method applies to molecules containing glucuronic acid hydrolysis under acidic conditions polysaccharide compounds, specificity is not strong. But the European Pharmacopoeia and the national drug standards were used in the determination of the law as a legal method.8.Protein content (on dry basis)≤0.1%In this study, five batches of SH samples measured by Folin-phenol protein content (%) is:0.17,0.21,0.18,0.23,0.19; measured by Coomassie blue protein content (%) is:0.0095,0.014,0.021,0.017,0.030. The former measurement results significantly higher than the latter. Coomassie blue method of high sensitivity, more suitable for the small proportion of protein SH sample.9.Heavy metals (as Pb)≤20ppmIn this study,1.0g SH is made through a series of chemical treatment25ml of the test solution; simultaneously preparing25ml of lead20ppm with standard control solution. In the control tube and pipe for the test solution were added thioacetamide solution2ml, after the color, the color of the test solution tube showing no deeper in the standard control tube.10.Bacterial count<100cfu/g; mold and yeast count<50cfu/g; Staphylococcus aureus, Pseudomonas aeruginosa, fecal coliforms are not detected.In this study, nutrient agar agar and rose bengal sodium bacterial counts were measured SH, mold and yeast count. Meanwhile. with the nutrient broth enrichment after streaked onto agar plates mannitol and sodium chloride coagulase test to detect Staphylococcus aureus. Furthermore, after enrichment with lactose bile inoculated crossed cetyltrimethylammonium bromide agar plates and oxidase test, pyocyanin tests to detect Pseudomonas aeruginosa; With double lactose bile medium at44℃-45℃cultured whether produce acid and gas, eosin methylene blue agar plates and indole test to detect fecal coliforms. |
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