Degradation kinetics and mechanism of pentoxifylline by ultraviolet activated peroxydisulfate

Abstract

Degradation of pentoxifylline (PTX) by sodium peroxydisulfate (SPDS) assisted by UV irradiation has been investigated in deionized water. The treatment was more favorable over direct photolysis or peroxydisulfate oxidation alone. The effects of various parameters, including different dosage of oxidant agent, PTX concentration, initial solution pH levels, and the presence of inorganic ions like chloride, nitrate and carbonate have been evaluated. The rate of PTX decomposition depends on the oxidant agent dose. The highest degradation was determined at pH 10.5, which can be explained by the generation of additional hydroxyl radicals (HOc) in the reaction between sulfate radicals and hydroxide ions. The presence of inorganic ions, especially the carbonate ions quench valuable sulfate radicals and have successfully retarded the PTX decomposition. Six PTX oxidation products were identified using UPLC-QTOF-MS for trials in a basic environment. The main degradation product (3,7-dimethyl-6-(5-oxohexyloxy)-3,7-dihydro-2H-purin-2-one) was isolated by column chromatography and identified by 1 HNMR and LC MS analyzes.

Stability of Pentoxifylline Injection: Application to Neonatal/Pediatric Care Setting

“…In regard to oxidative stress, our study showed that PTX degraded to multiple compounds (Figure S9). These results were consistent with the report by Kaminska and colleagues, 12 who identified one of the oxidative degradation products as 3,7-dihydro-3,7dimethyl-6-[(5-oxohexyl)oxy]-2H-purin-2-one, which we were able to acquire for the present study and found was one of the oxidative degradation products of PTX. By contrast, Mone and Chandrasekhar 10 identified one oxidative degradation product of PTX (1-(5,5-bishydroperoxy-hexyl)-3,7-dimethyl-3,7-dihydro-purine-2,6-dione), the further investigation of which was beyond the scope and focus of the present study.…”

“…The results of forced degradation studies were consistent with previous reports [10][11][12] that PTX was stable under acidic stress and subject to significant degradation under alkali and oxidative stress (Table S1). As shown by Mone and Chandrasekhar, 10 we found that alkali stress led to PTX degradation to at least two compounds with prominent peaks at 2.2 and 2.5 min (compared to PTX at 6.3 min; Figure S8).…”

“…Most available evidence indicates that PTX simple solutions are stable for > 10 d when exposed to light or in mild acidic conditions, but susceptible to alkali and peroxide degradation. [10][11][12] Furthermore, a recent report identified the principal degradation product following peroxide photolysis as 3,7-dihydro-3,7-dimethyl-6-[(5-oxohexyl)oxy]-2H-purin-2-one. 12 Regulatory guidance for conventional stability studies of pharmaceutical products is provided by authorities such as the European Medicines Agency (EMA), which also has guidelines for end-use and extemporaneously prepared medicines.…”

“…[10][11][12] Furthermore, a recent report identified the principal degradation product following peroxide photolysis as 3,7-dihydro-3,7-dimethyl-6-[(5-oxohexyl)oxy]-2H-purin-2-one. 12 Regulatory guidance for conventional stability studies of pharmaceutical products is provided by authorities such as the European Medicines Agency (EMA), which also has guidelines for end-use and extemporaneously prepared medicines. [13][14][15][16] In the context of the present study, guiding principles can be applied to the development of stability indicating analytical methods and investigations of drug stability in the end-use medicinal product.…”

A comparative study on the photo-catalytic degradation of Cytarabine anticancer drug under Fe3+/H2O2, Fe3+/S2O82−, and [Fe(C2O4)3]3−/H2O2 processes. Kinetics, identification, and in silico toxicity assessment of generated transformation products

“…Comparison of photo-Fenton with persulfate and Fenton-like treatments of CY , E 0 = 2.60 V), which can be produced by activation of peroxodisulphate, are an alternative oxidant that has been lately studied as degradation agent for several organic pollutants (Ding et al 2017, Ismail et al 2017, Soltani and Lee 2017. Also, sulfate radicals present a longer life-time than hydroxyl radicals (Gao et al 2016) and are more selective towards organic substrates reacting via direct electron transfer mechanism (Kamińska et al 2018, Matta et al 2011. In this study, SO 4…”