Química medicinal

Potentiometric and pHmetric Studies of Paracetamol

Abstract

Swaroopa Rani N Gupta

Acid-base titration of paracetamol in nonaqueous solvents was done. Procedure was followed for titration of paracetamol in different media like acetic acid, pyridine, dimethlformamide and ethyl alcohol with standard perchloric acid in glacial acetic acid, sodium ethoxide in ethyl alcohol using plantinum-calomel as well as glass-calomel electrode system. The equivalence point was located as accurately as possible by a differential graph of ΔE/ΔV or ΔpH/ΔV against V and concentration of test solution was computed. The acid-base titration of paracetamol is rapid and reproducible, and permits its determination in medicinal sample. The electrode systems vary with the solvent employed. The platinum-calomel electrode system is suitable where the solvent is glacial acetic acid in this case perchloric acid in glacial acetic acid is the titrant while the glass-calomel electrode system is suitable where the solvent is either pyridine, an alcohol or dimethyiformamide, the titrant consists of sodium ethoxide in ethyl alcohol.