Synthesis and characterization of a nanoemulsion system for solubility enhancement of poorly water soluble non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are highly used for the management and treatment of chronic and acute inflammation and to get relief from pain. It consists of a group of organic compounds having anti-inflammatory, anti-pyretic, and analgesic properties. However, majority of these drugs are poorly-water soluble leading to compromised bioavailability and hence limited therapeutic activity. In order to overcome these issues, we have studied the formulation, characterization, and cytotoxicity of NSAIDs, entrapped inside nanoemulsion droplets. NSAIDs-loaded nanoemulsions have been prepared by spontaneous aqueous titration method after the screening of excipients. On the basis of drug solubility study, the mixture of clove oil and isopropyl myristate has been selected as oil phase, whereas Tween 80 and isopropyl alcohol have been used as surfactant and co-surfactant respectively. The hydrodynamic sizes of Diflunisal and Niflumic acid-loaded nanoemulsions obtained from Dynamic Light Scattering (DLS) have been found in the range of 8-22 nm with the polydispersity index (PDI) below 0.5, implying fairly homogenous populations. The transmission electron microscopic (TEM) data supported the DLS results. However, the low zeta potentials of these nanodroplets suggest the formation of metastable nanoemulsions which have been further evaluated by various stress-stability studies. The cytotoxicity assay of the nanoemulsions loaded with poorly water-soluble drugs such as Diflunisal and Niflumic acid holds the promise of improved efficacy when administered via different routes such as oral, transdermal, or local application. (C) 2021 Elsevier B.V. All rights reserved.