Exploring the potential of N-methyl pyrrolidone as a cosurfactant in the microemulsion systems

The effect of N-methyl pyrrolidone (NMP) on the phase behavior of two ternary systems, viz. PEG-35-castor oil (Cremophore®EL)–glyceryl caprylate/caprate (Capmul® MCM)–water and PEG-35-castor oil (Cremophore®EL)–isopropyl myristate–water was studied. The study indicated that NMP has considerable influence on the phase behavior of both the systems. NMP increased the area of microemulsion formation in both the systems. Moreover, it also led to reduction/disappearance in the gelling region of the Cremophore®EL–isopropyl myristate–water system. These observations allowed us to conclude that NMP can be considered as a cosurfactant for the development of biocompatible microemulsions.