Abstract
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• Much interest has been shown on interaction between polymers and amphiphilic drugs because of their application in a variety of fields, such as pharmaceuticals, bioscience, etc. • Herein we report the interaction of a non-steroidal anti-inflammatory drug ibuprofen with various biocompatible polymers. • The critical aggregation concentration (
cac) and free energy of aggregation (Δ
G
agg
) are evaluated. • Among the neutral polymers, cellulose HPMC and HEC derivatives interact strongly as compared to PEG and PVP.
In this paper we are reporting the interaction of a non-steroidal anti-inflammatory drug ibuprofen (IBF) with various biocompatible polymers. Being amphiphilic, the drug interacts with the polymers similar to the interaction of surfactants and polymers. Therefore, we have considered the polymer–amphiphile interaction approach using conductimetry. The polymers of different charges (cationic, anionic, and nonionic) have been taken for the study. It was found that the critical aggregation concentration (
cac) decreases on increasing the polymer concentrations of cationic as well as nonionic polymers whereas it increases for anionic polymers. The results imply that anionic IBF interacts with cationic and nonionic polymers more strongly as compared to the anionic polymers. A possible anionic–anionic repulsion is responsible for the weak interaction of IBF with anionic polymers. On the other side, the critical micelle concentration (
cmc) increases for all polymers which is a usual indication of the interaction between amphiphiles and polymers. Free energies of aggregation (Δ
G
agg
) and micellization (Δ
G
mic
) were also computed with the help of degrees of micelle ionization obtained from the specific conductivity – [IBF] isotherms.