Surfactant enhanced reaction between benzocaine and pdimethylaminobenzaldehyde : study and its analytical application

Abstract EN

Benzocaine is well known as an insoluble substrate in water.

Therefore, its physical and analytical treatments in the presence of surfactant may allow organic solvents to be replaced by aqueous surfactants solutions.

The effect of the presence of anionic surfactant (sodium dodecyl sulfate, SDS) upon the condensation reaction of benzocaine with water insoluble p-dimethylaminobenzaldehyde (DAB) in aqueous solution has been investigated extensively.

The presence of 5 x 10-3M SDS increases the reaction rate by 20 times in contrast to that of a solution in 20 % ethanol.

A substantial increase in absorption band due to the formed Schiff base followed by a red shift has been observed.

A great advantage in analytical application resulting from the presence of surfactant due to the formation of a charge transfer complex has been reported.

The latter phenomenon has been realized and proved in this study, which depends merely on the charge of micelle surface.

A simple, accurate, and sensitive method for micro determination of benzocaine in aqueous surfactant solution has been introduced.

The proposed procedure for analysis of the presented drug in its bulk form and pharmaceutical formulations is more sensitive and accurate than that of the British pharmacopoeia method.

It has been concluded that the replacing of organic co-solvents by surfactants was not only captured for avoiding their pollution and toxic implication but there are some advantages gained from the presence of surfactant molecules.

The used surfactant compound (SDS) in this study is quite green and is commonly used as a detergent in toothpaste.