**8. Future perspectives**

system delivered genes more efficiently than liposomes [196]. Silva *et al* evaluated factors that influence DNA compaction in cationic lipid nanoemulsions [cationic nanoemulsions contain‐ ing stearylamine (a cationic lipid that presents a primary amine group when in solution, is able to compact genetic material by electrostatic interactions, and in dispersed systems such as nanoemulsions this lipid anchors on the oil/water interface conferring a positive charge to them)] [197]. The influence of the stearylamine incorporation phase (water or oil), time of complexation, and different incubation temperatures were studied. The complexation rate was assessed by electrophoresis migration on agarose gel 0.7%, and nanoemulsion and lipoplex characterization was done by dynamic light scattering (DLS). The results demonstrate that the best DNA compaction process occurs after 120 min of complexation, at low temperature (4 ± 1 °C), and after incorporation of the cationic lipid into the aqueous phase. Although the zeta potential of lipoplexes was lower than the results found for basic nanoemulsions, the granul‐ ometry did not change. Moreover, it was demonstrated that lipoplexes are suitable vehicles

Recently, considerable attention has been focused on the development of novel drug delivery systems for herbal drugs [198]. However some limitations of plant bioactives like instability in highly acidic pH and liver metabolism led to drug levels below therapeutic concentration in the blood resulting in less or no therapeutic effect [199]. Hence, encapsulation of plant extracts or its bioactives would minimize their degradation or presystemic metabolism, and serious side effects due to accumulation of drugs to the non-targeted areas and improves the ease of administration in the pediatric and geriatric patients [200]. Lipid nanoemulsions containing oil from medicinal plants or hydrophobic drugs have been shown to improve drug solubility, reduce side effects of various potent drugs, increase the bioavailability of drugs, and to prolong the pharmacological effects in comparison to conventional formulations such as conventional emulsions [201]. Formulation of nanoemulsions containing phytoactives have

The effect of nanoemulsion on intestinal absorption of colchicine was demonstrated *in vivo*. Colchicine nanoemulsion was prepared with isopropyl myristate, eugenol, Tween 80, ethanol and water, with eugenol being the oil phase in the formulation. Result obtained indicated that the intestinal absorption of colchicine was significantly enhanced by the nanoemulsion formulation [202]. Genistein has been shown to possess anticancer activities in different experimental systems, yet the same effects could not be translated in the clinical setting due to its poor bioavailability. Researcher have tried various nano approaches including incorpo‐ ration of genistein into topical nanoemulsion formulations composed of egg lecithin, medium chain triglycerides or octyldodecanol and water by spontaneous emulsification with improved activity [203]. Oil in water nanoemulsion formulation has also demonstrated increased anti-

for gene delivery.

110 Application of Nanotechnology in Drug Delivery

been reported.

inflammatory activity of curcumin [204].

**7. Nanoemulsions for phytopharmaceuticals**

Nanoemulsions are proposed for numerous applications in pharmacy as drug delivery systems because of their capacity to solubilize non-polar active compounds. Future perspec‐ tives of nanoemulsion are very promising in different fields of therapeutics or application in development of cosmetics for hair or skin. One of the versatile applications of nanoemulsions is in the area of drug delivery where they act as efficient carriers for bioactives, facilitating administration by various routes. The advantages and applications of nanoemulsions for oral drug delivery are numerous, where the droplet size is related to their absorption in the gastrointestinal tract. Due to the renewed interest in herbal drug formulation, nanoemulsion may be the ideal delivery platform for these difficult-to-formulate phytopharmaceuticals. The prospects of nanoemulsions lie in the ingenuity of formulation experts to utilize the advantages of nanoemulsion carriers in overcoming peculiar problems of drug delivery such as absorp‐ tion, permeation and stability of both orthodox and herbal drugs.
