Siriporn Okonogi a,*, Chadarat Duangrat a, Songyot Anuchpreeda b,
Suganya Tachakittirungrod a, Sombat Chowwanapoonpohn a
a Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand
b Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
Received 5 May 2006; received in revised form 3 July 2006; accepted 18 September 2006