Formula optimization of sustained-release ibuprofen tablet using simplex lattice design with mixture of caragenan, calsium sulphate, and PVP-K30 - Hadinugroho, Wuryanto; Faculty of Pharmacy, Universitas Katolik Widya Mandala Surabaya (Faculty of Pharmacy Universitas Gadjah Mada, Yogyakarta, Skip Utara, 55281, Indonesia, 2011)