Effect of gelatin protein on self-association behavior of sodium salt of ibuprofen drug in urea solution

Abstract

Herein, multi-techniques approaches such as conductometry, tensiometry, fluorometry, and FT-IR were engaged to evaluate the interaction between sodium salt of ibuprofen (IB) and gelatin (GN) at 298.15 K in 250 mmol·kg−1 urea (UR) solution. The current employed drug is used for relief of pain. The employed IB drug interacts through GN protein like the interaction between surfactants and polymers. It is clear that the graph obtained from the conductometric and tensiometry methods shows two clear breaks. Urea acts as water structure breaker and their presence in solution enhance in surface charge of aggregates occurs. The obtained first break spot is labeled critical aggregation concentration (cc) which is quit beneath the usual critical micelle concentration (cmc) besides this the subsequently break spot denotes second one is regarded as polymer saturation point (pp) and this akin to cmc. The interaction between IB and GN in UR solution increases as concentration of protein increases in the solution mixtures as clear from their obtained cc value because the value of cc reduces through enhancing the concentration of GN (%w/v), in spite of this the value of pp value increases with increase in concentration of GN means more drug needed for complete saturation of binding site of protein. In UR solution, the Gibbs free energy of micellization (ΔGmic) for singular IB was achieved negative exploring that micellization process is spontaneous in nature. The other different evaluated thermodynamic parameters such as free energy of aggregation (ΔGagg), free energy of transfer (ΔGt), etc. were found in favor of interaction between IB and GN. Fluorometry technique was utilized to find out the various parameters such as micropolarity, aggregation numbers (Nagg), etc. to verify the interaction amongst studied constituents and with the interaction between them were also assessed by FT-IR study.