ABSTRACT
Many potential drug candidates which had been screened to show therapeutic activities could not be formulated into suitable oral dosage forms, which are the most preferred form of drug administration, due to poor aqueous solubility. These compounds were abandoned during preformulation stage because they did not exhibit sufficient solubility in the aqueous environment, implying reduced bioavailability upon administration and the inability to attain the necessary drug levels in blood for therapeutic effect. Figure 1 depicts the possible events that can occur upon administrating various oral dosage forms and it is obvious that there are many factors affecting the absorption of drug.
