Determination of plumbagin in different parts of Plumbago zeylanica by RP-HPLC Pharmacokinetics of ligustilide in Ligusticum chuanxiong essential oil in rats in vivo Studies on stability of Baicalin Determination of content and entrapment efficiency of 20 (S)-protopanaxadiol in pharmacosomes by RP-HPLC method Determination of artemisimin in Artemisia annua with RP-HPLC