Synthesis and characterization of chlorhexidine acetate drug–montmorillonite intercalates for antibacterial applications

In this study, a drug intercalated montmorillonite (Mt) has been prepared which can be useful in designing novel topical drug delivery system. The drug–Mt intercalates were synthesized by ion exchange route where interlayer cations i.e., K+, Na+ etc. of Na+–Mt exchange with the cation of the drug, chlorhexidine acetate (Ca++). The characterization of drug–Mt intercalates has been done using X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric technique and energy dispersive X-ray analysis; all of which indicate successful intercalation of drug into the interlayer space. These drug–Mt intercalates strongly inhibited the growth of a wide range of microorganisms including both Staphylococcus aureus and Escherichia coli. In vitro release study of the antibacterial drug–Mt intercalates in phosphate buffer saline (pH 7.4) media at 37 °C was investigated. The pattern was found to be initially burst release followed by sustained release. The Ca++–Mt intercalates with a wide range of bioactivity against microbes and controlled release characteristics have the potential for application in the area of topical drug delivery.