**3.2 Nanoemulsions in biotechnology**

*Nanoemulsions - Properties, Fabrications and Applications*

*3.1.2 Oral and topical drug delivery systems*

*Applications of nanoemulsions in drug delivery [31].*

**Figure 6.**

preferred form of drug administration.

*3.1.3 Ocular and pulmonary drug delivery*

delivered using nano emulsions.

Owing to patient compliance, convenience, ease of formulation and higher absorption in the intestine, oral drug delivery is the most widely distributed and

Topical drug delivery also has several advantages over other modes of drug administration such as the avoidance of hepatic first pass metabolism, reduction of toxicity and targeted drug delivery to the affected portion of the skin. Here selfadministration is also possible. The transparent nature and fluidity of nanoemulsions not only gives a pleasant skin feel but also helps in eliminating the drug input

Owing to the large surface area of the droplets, nanoemulsions enable rapid penetration of active ingredients through the skin. This is one of the most valuable properties of nanoemulsions due to which the use of special penetration enhancers

For the treatment of eye diseases, drugs are delivered topically in ocular dosage forms such as solutions, suspensions and ointments. Due to physiologically

by just removing the transdermal patch without any irritation [32].

which cause incompatibility of the formulation can be minimized [33].

When compared to conventional oral formulations, nano emulsion formulations provide several benefits in oral drug administration. Some of these benefits include increased absorption, improved clinical potency and decreased drug toxicity [33]. Hence, drugs such as steroids, hormones, diuretics and antibiotics can be ideally

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Nanoemulsions serve as a waterproof medium for bio-catalytic or enzymatic reactions to occur. The enzymes in low water content exhibit greater solubility in non-polar reactants and higher thermal stability. As a result, the thermodynamic equilibrium also shifts towards condensation [36].

Reactions such as synthesis of esters, peptides and sugar acetals transesterification, hydrolysis and steroid transformation are catalyzed by enzymes in nanoemulsions. Lipases are the most widely used class of enzymes in microemulsion-based reactions [33].
