Transesterification Reactions of Parabens (Alkyl 4‐Hydroxybenzoates) with Polyols in Aqueous Solution

Interaction of methylparaben preservative with selected sugars and sugar alcohols

“…The failure to observe any reaction products was most likely due to the harsh reaction conditions that were used in their experiments (90°C for 3 h at unspecified pH) 24. It is well known that sugars are much less stable than sugar alcohols.…”

“…In theory, transesterification reaction could occur between parabens and any molecules containing hydroxyl groups. However, no such study on the reaction with sugars has been reported in the literature except one unsuccessful attempt, in which no reaction products between methylparaben and aldoses, for example, ribose, xylose, or cellobiose, were observed 24…”

“…Although hydrolysis is the most frequent degradation reaction in aqueous pharmaceutical formulations, other factors may also decrease the antimicrobial activity of the parabens such as sorption onto solid9–11 and plastic container,12–14 solubilization by nonionic surfactants,15–17 partitioning into flavoring oils,18 and perhaps more importantly interaction/reaction with excipients. A wide range of excipients have been reported to interact/react with parabens, which include cellulose derivatives,19 ethanol,20 ethanolamine,21 β‐cyclodextrin,22 and sugar alcohols (or polyols) 23–26. In this article, we report the interaction of methylparaben with selected sugars through transesterification reaction, which to our best knowledge has not been reported in the literature.…”

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“…[6] This transesterification reaction determined by previously published studies indicated that the hydroxyl groups in a sugar alcohol molecule (3,4,5 carbon sugar alcohols) can react with methylparaben and cause possible incompatibility due to the formation of 6 isomer products. [16][17][18] To get a proper knowledge about the stability of drugs in its dosage form, a thorough study is required about the drug and excipients that are present in the formulation. However, for this purpose, an appropriate and validated analytical method is required that must be capable to analyze the cetirizine in pharmaceutical preparations.…”

Drug-Excipient Interactions: Case Studies and Overview of Drug Degradation Pathways

“…During the stability, study of an experimental batch of an oralsuspension formulation that contained sorbitol and paraben preservatives shows approximately 1% degradation for the samples stored at 30˚C for one year (Figure 11). 3, 4, 5 carbon sugar alcohols reacts with methyl paraben to form 6 isomer products were identified by HPLC and NMR by Minhui Ma et al [28]- [30].…”