DEVELOPMENT AND VALIDATION OF A HPLC METHOD FOR DETERMINATION AND QUANTIFICATION OF RUBRAXANTHONE IN STEM BARK EXTRACT OF MANGOSTEEN - Susanti, Meri; Faculty of Pharmacy, Andalas University, Kampus Limau Manis, Padang -25163 PO. Box 143, Indonesia (Faculty of Pharmacy Universitas Gadjah Mada, Yogyakarta, Skip Utara, 55281, Indonesia, 2014)