Characterization of the Partition Rate of Ibuprofen Across the Water-Octanol Interface and the Influence of Common Pharmaceutical Excipients

Abstract

This work reports the measurement of the partition rate of a model drug, ibuprofen (IBU), from aqueous solutions into octanol in the absence and presence of common pharmaceutical excipients including glucose, lactose, maltoheptaose, hydroxypropyl methylcellulose, polyvinylpyrrolidone, polyvinylpyrrolidoneevinyl acetate, hydroxypropyl methylcellulose AS, sodium dodecyl sulfate, Tween 80, and sodium taurocholate at varying concentrations. This attempts to assess the kinetic aspect of IBU partitioning across the water-octanol interface by applying a mechanistic model and to characterize the interfacial resistance. A significant reduction in P i across the water-octanol interface was observed with extremely low concentration of the selected excipients in the aqueous media. These results reveal the presence of a surface excess of adsorbed excipients at the water-octanol interface. The retardation of the P i of IBU was found to be sensitive to (1) the molecular weight or the degree of polymerization of these excipients, (2) the hydrodynamic condition of the experimental method, and (3) the pH of the aqueous media. Retardation of the P i of IBU in the presence of excipients observed in this study is proposed by a steric obstruction mechanism through the adsorbed surface excess layer of excipients located at the water-octanol interface.

A Rational Design of a Biphasic Dissolution Setup—Modelling of Biorelevant Kinetics for a Ritonavir Hot-Melt Extruded Amorphous Solid Dispersion

“…In contrast, the calculated partitioning rate in the plain buffer (k part = 0.023 min −1 ) during the early intestinal time period starting at 30 min was little faster (Table 7) resulting in an increased onset of dissolved ritonavir in the organic phase ( Figure 9). The difference in the kinetics can be explained by the presence of surfactants in the two biorelevant media, which could lead to a higher affinity of the API in the aqueous phase, and potentially influence the 1-decanol/buffer interface [53].…”

Generic Nature of Interfacial Phenomena in Solutions of Nonionic Hydrotropes

“…Hydrotropes together with surfactants and solid dispersed particles can be used in oil spill dispersants . Hydrotropes solubilize hydrophobic substances in mesoscopic droplets and affect the kinetics of hydrophobe partition in water and oil phases, which is promising for pharmaceutical applications. , Thus, the generic duality of hydrotropes’ behavior in bulk and at fluid interfaces opens up new opportunities for various applications and research.…”