ABSTRACT
Paracetamol is an antipyretics and analgesic drug, while ascorbic acid, also known as Vitamin C, is a water-soluble vitamin found in food and used in the treatment of scurvy. This study investigated the extent of plasma protein binding of paracetamol and ascorbic acid binding and determination of their binding sites.
The degree of binding of paracetamol and ascorbic acid to plasma protein and 4% bovine serum albumin (BSA) were investigated. The degree of binding was determined by equilibrium dialysis method while the concentrations of the drugs were determined using spectrophotometric method and the binding site of both drug was calculated from the equation of the percentage binding.
The degree of binding of paracetamol to plasma proteins for concentrations between 2 - 10 µg/mL was 46 - 35%. In the presence of ascorbic acid it was 40 - 34%. The binding of paracetamol to 4% BSA at the same concentration was 40% - 34%.
The binding of ascorbic acid (2 - 10 µg/mL) to plasma proteins was 43 - 31% while the protein binding of ascorbic acid in the presence of paracetamol, was 43 - 34%, and ascorbic acid binding to 4% bovine serum albumin, was 43 - 34%. The number of binding sites per molecule of protein for paracetamol was 2, and that of ascorbic acid was 3. The results showed no significant difference in the protein binding of paracetamol in the presence of ascorbic acid and vice versa, hence their bioavailability may not be significantly altered on co-administration.
