Why there is so much variation in skin permeation study (in vitro)?
The experiments even if done on two different days should not have much variation. SD and SE is coming so high (30-70 ug/cm2). My sampling method is same every time. I do not face this problem with release study using dialysis membrane using same sampling procedure, medium and HPLC method then why I am facing this in Skin permeation using franz diffusion cell? Is this normal (give reference) or tell me possible cause of error to rectify this.?