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Merck

The ascorbyl palmitate-polyethyleneglycol 400-water system phase behavior.

Colloids and surfaces. B, Biointerfaces (2011-10-15)
Luciano Benedini, Paula V Messina, Santiago D Palma, Daniel A Allemandi, Pablo C Schulz
RESUMEN

Ascorbyl palmitate (Asc16) in polyethyleneglycol 400 (PEG 400)-water mixtures at weight fractions (w/w) between 0.05 and 1.0 were studied by differential scanning calorimetry (DSC) and polarizing microscopy (PM) at different temperatures. The employed PEG 400-water proportions were: 0-25-50% and 75% of polymer. A complete phase diagram was determined for each PEG 400-water mixture. A cubic mesophase and two (probably three) lamellar mesophases were detected in different regions of the phase diagrams. The addition of PEG 400 to the Asc16-water system shifts the limits of the liquid crystalline domains to lower temperature and surfactant concentration. At weight fraction of PEG 400≥50%, the limits of the domain of existence of cubic mesophase shift to low surfactant concentration compared with water-rich systems. The hydrated crystals are Asc16.2·6H(2)O. If the proportion of water is lower than that value, a mixture of hydrated and anhydrous crystals appears. Heating these crystals produce waxy crystals having melted hydrocarbon bilayers retaining their crystalline structure because the polar bilayers are still rigid.

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6-O-Palmitoyl-L-ascorbic acid, BioXtra, ≥99.0% (RT)
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Ascorbic acid 6-palmitate, meets USP testing specifications
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