Stability of ascorbyl palmitate in topical microemulsions

• Published in: International journal of pharmaceutics Vol. 222; no. 2; pp. 271 - 279
• Main Authors: Špiclin, P, Gašperlin, M, Kmetec, V
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 17.07.2001; Elsevier
• Subjects: Administration, Topical; Applied sciences; Ascorbic Acid - analogs & derivatives; Ascorbic Acid - chemistry; Ascorbyl palmitate; Biological and medical sciences; Chemical industry and chemicals; Chemistry, Pharmaceutical; Chromatography, High Pressure Liquid; Cosmetics, toiletries; Drug Carriers; Drug Stability; Emulsions; Exact sciences and technology; General pharmacology; Medical sciences; Microemulsions; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Sodium ascorbyl phosphate; Stability; Topical; Washing products. Cosmetics and toiletries. Perfumes; Topical; Stability; Microemulsions; Ascorbyl palmitate; Sodium ascorbyl phosphate; Pharmaceutical technology; Chemical stability; Conservation; Cosmetology; Triglyceride; Property formulation relationship; Ethylene oxide polymer; Ascorbic acid derivatives; Water oil microemulsion; Light; Dosage form; Chemical properties; Oil water microemulsion; Physicochemical properties
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/S0378-5173(01)00715-3

Ascorbyl palmitate and sodium ascorbyl phosphate are derivatives of ascorbic acid, which differ in stability and hydro-lipophilic properties. They are widely used in cosmetic and pharmaceutical preparations. In the present work the stability of both derivatives was studied in microemulsions for topical use as carrier systems. The microemulsions were of both o/w and w/o types and composed of the same ingredients. The stability of the less stable derivative ascorbyl palmitate was tested under different conditions to evaluate the influence of initial concentration, location in microemulsion, dissolved oxygen and storage conditions. High concentrations of ascorbyl palmitate reduced the extent of its degradation. The location of ascorbyl palmitate in the microemulsion and oxygen dissolved in the system together significantly influence the stability of the compound. Light accelerated the degradation of ascorbyl palmitate. In contrast, sodium ascorbyl phosphate was stable in both types of microemulsions. Sodium ascorbyl phosphate is shown to be convenient as an active ingredient in topical preparations. In the case of ascorbyl palmitate, long-term stability in selected microemulsions was not adequate. To formulate an optimal carrier system for this ingredient other factors influencing the stability have to be considered.