**14. Dermal and transdermal delivery of phytopharmaceuticals**

Novel drug delivery system is a novel approach to drug delivery that addresses the limitations of the traditional drug delivery systems. Phytopharmaceuticals are pharmaceuticals using traditional compounds derived from botanicals instead of chemicals. Because these natural ingredients are more easily and more readily metabolized by the body they produce fewer if any side effects and provide increased absorption in the bloodstream resulting in more thorough and effective treatments unlike pharmaceuticals produced from chemical com‐ pounds which are prone to adverse side effects [157]. The formulation of dermal and trans‐ dermal delivery of phytopharmaceuticals is gaining interest owing to the benefits accruable from it. One of the first few attempts to utilize TDDS containing phytopharmaceuticals was investigation aimed to formulate transdermal films incorporating herbal drug components such as boswellic acid (*Boswellia serrata*) and curcumin (*Curcuma longa*), which utilizes skin as a site for continuous drug administration into the systemic circulation [157]. TDDS avoids first pass metabolism of the drug without the pain associated with injection; moreover the system provides a sustained drug delivery with infrequent dosing via zero-order kinetics and the therapy can easily be terminated at any time. For the local action of the drug at the site of administration of TDDS, turmeric are used which is considered a new version of ayuverdic turmeric *poultic*e or *lepa* [158].

Application of vesicular encapsulation holds great promise in the development and use of phytomedicines considering the difficulties of their formulation into stable dosage forms. Certain physicochemical properties of many herbal extracts make their formulation difficult due to stability and processing challenges. By using appropriate techniques, vesicular products of herbal extracts with enhanced stability and efficacy have been produced. A new drug delivery device known as phytosome, composed of phosphatidylcholine, has been developed to overcome the poor absorption of flavonoids, a challenge due mainly to their large molecular sizes and poor miscibility with the lipid contents of cell membrane linings [159]. Phytosomes are well absorbed when taken orally.

Evaluations of phytosomes indicate that a bond is formed between a flavonoid and a phos‐ phatidylcholine molecule to form a hybrid that is highly lipid-miscible. The development and applications of a variety of novel vesicular herbal formulations such as liposomes, phytosomes, transfersomes and ethosomes have been reported [160,161]. Ethosomes, by virtue of their special characteristics, may circumvent the hindrances to successful delivery of phytomedi‐ cines. Both soluble and insoluble phytomedines can be encapsulated in ethosomes. Ethosomes also offer protection from premature degradation and increased biodistribution, which would make for improved bioavailability and more beneficial therapeutic outcome for TDDS.
