A Contribution to control The dissolution Properties of some Drugs Formulated in Solid dosage forms

The oral route remains the most convenient way of delivering drugs. Oral administration presents a series of attractive advantages towards other drug delivery (Shaji and Patole, 2008). These advantages are particularly relevant for the treatment of pediatric patients and include the avoidance of pain and discomfort associated with injectable route. Moreover, oral formulations are less expensive. The therapeutic efficacy of a drug product intended to be administered by the oral route depends first of all on its absorption by the gastrointestinal tract (Lheritier et al., 1995).Drug absorption depends on the lipid solubility of the drug, its formulation and the route of administration (Pleuvry, 2005). A drug needs to be lipid soluble to penetrate membranes unless there is an active transport system or it is so small that it can pass through the aqueous channels in the membrane. Typically drugs of the later type are distributed into total body water. For weakly acidic and weakly basic drugs, absorption and distribution are pH dependent since only the unionized drug is lipid soluble. Strongly ionized drugs can’t cross membranes so they are not absorbed orally and can’t cross the blood-brain barrier. Traditional oral or parenteral administration may not achieve optimum therapeutic concentrations of drug at its site of action. After oral administration, metabolism of the drug in the gut or liver may result in low systemic bioavailability.Of all the orally administered dosage forms, tablet is most preferred because of easy administration, compactness and flexibility in manufacturing (Raghavendra et al., 2009). Tablets are solid preparations containing a single dose of one or more active substances and usually obtained by compressing uniform volumes of particles (B.P, 2010). The particles consist of one or more active substances with or without excipients such as diluents, binders, disintegrating agents, glidants and lubricants, substances capable of modifying the behavior of the preparation in the digestive tract, coloring matter and flavoring substances.