**5. Applications of microemulsion**

Microemulsion are being used in many areas.

a. **Drug delivery**: Microemulsion formulation has been extensively used in drug delivery. From the last few decades, the microemulsion system has been used in a variety of drug delivery systems like oral, topical, parenteral, and oral.

regulators. Five major categories of bioactive compounds are (1) nitrogen compounds (primarily alkaloids), (2) terpenoids, (3) phenolics, (4) proteinase inhibi-

*Microemulsion Formulation of Botanical Oils as an Efficient Tool to Provide Sustainable…*

Many bioactive compounds (phytochemicals) have been discovered by the researchers who have good repellent activity against insect pests [10]. These botanical-based repellents not only have excellent repellency but also influences the physiology of insect. These botanical bioactive agents (phytochemicals) can effectively replace the presently available synthetic pesticides against the mosquito.

Essentials are potent pesticides. But still, exploitation of them in pure form is not

a. **Water solubility:** Essential oils are water-insoluble due to fatty acids and cannot be dispersed uniformly in water before application [11]. Nonuniformity during use creates the problem of dispersion over the applied

b. **Penetration:** Essential oils in a pure form not penetrate in the targeted area

c. **Shelf life:** In the pure form, shelf life of essential oil decreases and their constituents starts degrading in the open atmosphere by light, pH,

**6.2 Microemulsion system: a practical approach to solve the inefficiencies**

Microemulsions are the thermodynamically stable isotropic solution of nanodispersions of size 10–200 nm. These are highly stabilized solutions with surfactants and co-surfactants [14, 15]. These microemulsion systems provide effective delivery systems, give extended shelf life, easy to prepare, and can easily

In microemulsion physio-chemical parameters of essential oil changes like improvement insolubilization, better bioavailability, and enhance the rate of penetration in targeted sites without any wastage [14, 17] in addition to this essential oil bio-constituents spreading capacity in aqueous solution improves and gives uniform dispersion on targeted sites after application [18] and provide good bioefficacy [19]. Moreover, in microemulsion formulation, essential oil active ingredient degradation rate decreases and enhances their shelf life for an extended period [20]. Further, due to the smaller droplet size in microemulsion also enhances wetting, spreading, and permeability and uniformly deposited over leaf surfaces [21, 22]. Characteristic features of essential oil microemulsion have been

Microemulsions can incorporate the natural oil or essential oil in a high amount in water without any destabilization of active constituents. Essential oil gives a superstability performance in microemulsion form as compared to emulsion forms [23]. The essential oil has many potential active ingredients that give very good bioefficacy in insect pests. Hence, essential oil could be a better alternative to

**6.3 Available essential oil microemulsions and targeted pest**

areas. It is the main ineffectiveness of essential oil application.

and wash off by rain or evaporated quickly by air [12].

encouragable in the agriculture because of the following reasons:

tors, and (5) growth regulators [9].

*DOI: http://dx.doi.org/10.5772/intechopen.91788*

**6.1 Issues with essential oils in agriculture**

temperature variations, etc. [13].

**of essential oil in crop protection**

scalable by low input of energy [16].

highlighted in **Figure 5**.

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Besides, the applications mentioned above, microemulsion formulation also find its applications in the following fields:

