1.Physicochemical properties of the drug 1.1.SOLUBILITY 1.Significance Intrinsic solubility (Co dissociation constant(pKa) Co will immediately indicate need and pKa possibility of making more soluble form (salt)of the drug to eliminate solubility-related poor bioavailability,particularly with solid dosage form. Kaplan(1972):37 C,pH1-7,solubility<1%(10mq/ml). absorption problem,dissolution-limited absorption1. Physicochemical properties of the drug Physicochemical properties of the drug 1.1. SOLUBILITY 1.1. SOLUBILITY 1.Significance 1.Significance z Intrinsic solubility (C0) z dissociation constant (pKa) C0 will immediately indicate will immediately indicate need and pKa possibility possibility of making more soluble form (salt) of the drug to eliminate making more soluble form (salt) of the drug to eliminate solubility solubility-related poor bioavailability, particularly with related poor bioavailability, particularly with solid dosage form solid dosage form. Kaplan(1972): 37 Kaplan(1972): 37℃, pH1-7, solubility<1%(10mg/ml), solubility<1%(10mg/ml), absorption problem, dissolution absorption problem, dissolution-limited absorption limited absorption