==Skin whitening ingredients and enhanced bioavailability==
===Bioavailability===
[[Image:Bioavailabilitybioavail.jpg|500px|thumb|right|[http://www.spitalpharmazie-basel.ch/pdf/Diss_Pellanda.pdf Schematic depiction of percutaneous absorption,Pellanda(2006)]]]
The determination of the bioavailability of systemically absorbed products is defined as the rate and extent to which the active ingredient or active moiety is absorbed from the drug product and becomes available at the site of action [http://www.omicsonline.org/0975-0851/JBB-02-102.pdf Kanfer and Shargel, 2008]. However, when considering products which contain active ingredient(s) not intended for systemic absorption, the US FDA, published the following statement in the US Federal Register (US Federal Register, 2009) where such products“...... may be assessed by (surrogate) measurements intended to reflect the rate and extent to which the active ingredient or moiety becomes available at the site of action”.
*Nanoemulsions- Nanoemulsions are emulsions having small droplet size (20–300nm). They could be used for lipophilic as well as hydrophilic substances with enhanced bioavailability
[[Image:newer approach2Newer_approach2.jpg|850px|thumb|center|[http://www.ncbi.nlm.nih.gov/pubmed/18482010 Chanchal & Swarnalata,2008]]]
Researcher also used skin penetration enhancer, volatile silicone and several other organic compound which make the ingredients stable and more bioavailable to the skin.