Evaluation of heat-conduction microcalorimetry in pharmaceutical stability studies VII. Oxidation of ascorbic acid in aqueous solution

Angberg, M.; Nyström, Christer; Castensson, Staffan

doi:10.1016/0378-5173(93)90292-n

Cited by 31 publications

(13 citation statements)

References 16 publications

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“…It was found that oxidation rate of Ascorbic Acid was dependent on the availability of oxygen and its dissolution in the head space of the vial. Therefore, the amount of oxidation was higher at the beginning when oxygen content was high and directly available in the solution, and the percentage decrease in ascorbic acid was greater in the first 5 h (38). Although in our work the experiment was carried out for 4 h, however, as with commercial facial masks, the nanofiber mat formulation is intended to be placed on the skin surface for no more than 15 min, which will decrease the oxidation rate of ascorbic acid.…”

Section: Skin Permeationmentioning

confidence: 99%

Novel Vitamin and Gold-Loaded Nanofiber Facial Mask for Topical Delivery

et al. 2010

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Abstract. L-ascorbic acid has been widely used in cosmetic and dermatological products because of its ability to scavenge free radicals and destroy oxidizing agents. However, it is chemically unstable and can easily be oxidized. The current cosmetic facial masks available in the market are pre-moistened, which means that the aqueous fluid content of the mask may oxidize some of the unstable active ingredients such as ascorbic acid. This work presents an anti-wrinkle nanofiber face mask containing ascorbic acid, retinoic acid, gold nanoparticles, and collagen. This novel face mask will only be wetted when applied to the skin, thus enhancing product stability. Once moistened, the content of the mask will gradually dissolve and release the active ingredients and ensure maximum skin penetration. The high surface areato-volume ratio of the nanofiber mask will ensure maximum contact with the skin surface and help to enhance the skin permeation to restore its healthy appearance. Electrospun fiber mats may provide an attractive alternative to the commercial facial cotton masks.

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Section: Skin Permeationmentioning

confidence: 99%

Novel Vitamin and Gold-Loaded Nanofiber Facial Mask for Topical Delivery

et al. 2010

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“…Angberg et al [34] observed that the measured heat-flow increased with increasing ascorbic acid concentration up to a certain concentration whereupon further increases did not increase the power response. It was presumed the reaction became limited by the oxygen concentration at higher acid concentrations.…”

Section: Stability Assessment Of Individual Compoundsmentioning

confidence: 97%

“…Ascorbic acid oxidises reversibly in aqueous solution to form dehydroascorbic acid which is subsequently irreversibly hydrolysed to give diketogluonic acid. Angberg et al [34] noted that the heatflows measured for solutions of ascorbic acid in pH 4.9 and pH 3.9 buffers were greater for those samples that were prepared with an air space in the ampoule compared with those that were not. Furthermore, if the solution was purged with nitrogen prior to loading, the heat-flow dropped nearly to zero.…”

Section: Stability Assessment Of Individual Compoundsmentioning

confidence: 98%

“…A simple methodology to determine the presence of oxidative degradation is to run samples in closed ampoules under either air or nitrogen; differing power-time profiles indicate that oxidation is occurring. For example, varying the oxygen content in an ampoule containing an aqueous solution of ascorbic acid varies the power-time signal obtained [34][35], indicating the presence of an oxidative process. Ascorbic acid oxidises reversibly in aqueous solution to form dehydroascorbic acid which is subsequently irreversibly hydrolysed to give diketogluonic acid.…”

Section: Stability Assessment Of Individual Compoundsmentioning

confidence: 99%

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Stability Assessment of Pharmaceuticals and Biopharmaceuticals by Isothermal Calorimetry

Gaisford¹

2005

CPB

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The assessment of stability (of actives, excipients and/or formulated products) is an important, and often time-consuming, part of pharmaceutical product development. Conventionally, HPLC is used to quantify the concentrations of a parent compound and any degradation products as a function of storage time. HPLC, however, is relatively insensitive to small changes in concentration and it is often the case that stability assays are conducted under stress conditions, in order to accelerate any degradation processes. The Arrhenius relationship is then employed to give an initial prediction of stability under storage conditions while long-term studies, under storage conditions, are conducted to confirm these predictions. The properties of isothermal calorimetry, such as its intrinsic sensitivity to small changes in heat and invariance to the physical form of a sample, make it ideally suited for stability assessment because it obviates the need for an Arrhenius analysis. In addition, the ability to conduct titration or gas perfusion experiments vastly increases its range of applications. Recent advances in instrumental design and data analysis have made it easier to analyse data quantitatively for complex systems. It is the purpose of this review to highlight some of these developments, discuss them in the context of pharmaceutical and biopharmaceutical examples and explore some of the future challenges and applications of the technique.

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“…[12][13][14][15][16][17] The theoretics found in the literature was the comparison of the standard oxidation (or reduction) potentials of antioxidants and that of drugs. 18) According to the theoretics of physical chemistry, these standard potentials are related to DG 0 and K, the increment of standard Gibbs function and the equilibrium constant of the chemical reactions.…”

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confidence: 99%

Compressed Oxygen in Drug Stability Experiments

Yan

Lin

et al. 2007

CHEMICAL & PHARMACEUTICAL BULLETIN

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A drug stability experiment accelerated by compressed oxygen was established. The stability of 10% ascorbic acid solution as a model was studied and the kinetic parameters were obtained with the newly established experimental method. Because ascorbic acid degrades under both anaerobic and aerobic conditions, the total rate constant k total can be expressed as: k total ‫؍‬k anaerobic ؉k aerobic , where k anaerobic and k aerobic are the rate constants of anaerobic and aerobic degradations, respectively. The k anaerobic can be expressed as k anaerobic ‫؍‬ A anaerobic · exp(؊E a,anaerobic /RT ) according to Arrhenius equation, and the k aerobic was found to be k aerobic ‫؍‬ A aerobic · exp(؊E a,aerobic /RT ) · p O 2 in our study.

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Evaluation of heat-conduction microcalorimetry in pharmaceutical stability studies VII. Oxidation of ascorbic acid in aqueous solution

Cited by 31 publications

References 16 publications

Novel Vitamin and Gold-Loaded Nanofiber Facial Mask for Topical Delivery

Novel Vitamin and Gold-Loaded Nanofiber Facial Mask for Topical Delivery

Stability Assessment of Pharmaceuticals and Biopharmaceuticals by Isothermal Calorimetry

Compressed Oxygen in Drug Stability Experiments

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