Oxidative Susceptibility Testing

Boccardi, Giovanni

doi:10.1201/9780849359194.ch7

Cited by 17 publications

(24 citation statements)

References 0 publications

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“…This shows that significantly more TCA degraded than copper was present, indicating that copper catalyzed the reaction. Copper, or other trace metals, as oxidation catalysts is further supported by literature (2,11,13). This indicates that TCA oxidation can be catalyzed and hence, significantly increased even if only small traces of metal impurities are present.…”

Section: The Influence Of Trace Metal Content On Tca Degradation Conssupporting

confidence: 56%

“…Competition for Cu(Ac) 2 between TBPB and TCA can explain the difference in degradation between the samples with Cu(Ac) 2 alone and those with both Cu(Ac) 2 and TBPB. Moreover, the hydroxyl radicals (HO•) that form during Fenton-type reactions are much more reactive than the natural oxidant (ROO•) (11,13). Even in this environment, TCA degraded less than in the presence of Cu(Ac) 2 alone; affirming TCA oxidation is mediated by trace metals and oxygen rather than peroxides.…”

Section: The Degradation Mechanism Of Tcamentioning

confidence: 98%

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The Role of Excipients in the Stability of Triamcinolone Acetonide in Ointments

Heugten

Vries²,

Markesteijn³

et al. 2018

AAPS PharmSciTech

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Abstract.Degradation of triamcinolone acetonide (TCA) in an ointment was investigated. TCA appeared to be concentrated in propylene glycol (PG) which in turn is dispersed in a lanolin-petrolatum mixture. Two predominant degradation products were identified: a 21-aldehyde and a 17-carboxylic acid. The 21-aldehyde is formed after TCA is oxidized by O 2 , a reaction that is catalyzed by trace metals. Logically, the content of trace metals has a profound effect on the degradation rate. It was shown that trace metals are extracted from lanolin and petrolatum by PG, increasing the concentration in PG. In accordance with these findings, TCA degrades faster in PG that is present in the ointment formulation than in regular PG. The 21-aldehyde was confirmed to be a primary degradation product, while the 17-carboxylic acid was identified as a secondary degradation product. Based on the mechanism of degradation, the ointment can be stabilized by the addition of sodium metabisulfite which was shown to reside also in the PG phase within the ointment.

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Section: The Influence Of Trace Metal Content On Tca Degradation Conssupporting

confidence: 56%

Section: The Degradation Mechanism Of Tcamentioning

confidence: 98%

The Role of Excipients in the Stability of Triamcinolone Acetonide in Ointments

Heugten

Vries²,

Markesteijn³

et al. 2018

AAPS PharmSciTech

View full text Add to dashboard Cite

show abstract

“…Commonly used methods like peroxide content measurement such as the FOX assay used as a measure of oxidant concentration are not feasible for hydrogels due to high viscosity. A measure of free radical concentration is an indicator of oxidative instability, as free radical reactions are involved in the common oxidative degradation pathways in pharmaceutical formulations 16–18. Since, EPR measurements are not affected by the viscosity of the sample it can be used to monitor the concentration of radicals.…”

Section: Resultsmentioning

confidence: 99%

The fate of free radicals in a cellulose based hydrogel: Detection by electron paramagnetic resonance spectroscopy

Basumallick¹,

Ji²,

Naber

et al. 2009

Journal of Pharmaceutical Sciences

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“…Amines, sulfides, and carbon-carbon double bonds are susceptible to oxidation using hydrogen peroxide to give corresponding N-oxides, sulfoxides (or sulfones), and epoxides, respectively. These functional groups are prone to electrophlilic attack, and the reactions are ionic and do not involve free radicals [38]. Another, more predictive oxidative system would include forced degradation by purging the headspace with oxygen.…”

Section: Forced Degradation Studies (Solid State and Solution)-drug Smentioning

confidence: 99%