Factors affecting formation of nanoemulsions containing modified coconut oil and spearmint oil Kamonchanok Wangjit a,b , Chutima Limmatvapirat c , Nattawat Nattapulwat a , Wanchai Sutananta a , Sontaya Limmatvapirat a,b, * a Department of Pharmaceutical Technology, Faculty of Pharmacy, Silpakorn University, Nakhon Pathom 73000, Thailand b Pharmaceutical Biopolymer Group (PBiG), Faculty of Pharmacy, Silpakorn University, Nakhon Pathom 73000, Thailand c Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Silpakorn University, Nakhon Pathom 73000, Thailand ARTICLE INFO Article history: Available online 25 November 2015 Keywords: Coconut oil Spearmint oil Nanoemulsions Dental caries is one of the major oral health problems in most countries, affecting more than 50% of school children and ma- jority of adults. Normally, we can prevent the disease by utilization of suitable antiseptics, e.g. alcohols and chlorhexidine [1]. However, most antiseptics cause irritation or straining of the mucous membrane and teeth. Therefore, finding a more safe and efficient antiseptics is still a matter of interest to eradi- cate the causative pathogen.Volatile oils from plants including spearmint oil (SMO) could reduce the number of Streptococcus mutans counts in plaques and saliva. Recently, modified coconut oil (MCO) was also introduced as an alternative antimicrobial agent against various microbes. However, the oils are diffi- cult to incorporate into aqueous solutions for oral administration because they have a limited water solubility. Thus, the development of alternative dosage forms should be further investigated. Nanoemulsions are one of the popular systems since they are compatible with water, can be easily removed, are safe and a large amount of oils could be loaded [2] . Therefore, formulation of spearmint and MCO into nanoemulsions should be a possible troubleshooting. To investigate the formation of nanoemulsions, the pseudo- ternary phase diagrams were constructed by a previously described method [3]. The combinations of MCO and SMO with the mass ratios of 100:0, 75:25, 50:50, 25:75 and 0:100 were used as oil phase. Each oil phase and aqueous solution of Cremophor ® RH-40 (surfactant) was mixed in the test tube. The 95% v/v ethanol (co-surfactant) was then added and mixed thor- oughly by a vortex mixer.The mixture was checked under light versus a dark background to check for clearness, cloudiness or phase separation. The clear isotropic region or the mis- * E-mail address: sontayal@hotmail.com. Peer review under responsibility of Shenyang Pharmaceutical University. http://dx.doi.org/10.1016/j.ajps.2015.11.023 1818-0876/© 2016 Production and hosting by Elsevier B.V. on behalf of Shenyang Pharmaceutical University.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). asian journal of pharmaceutical sciences 11 (2016) 227–228 Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/ajps HOSTED BY ScienceDirect