Simultaneous RP-HPLC for estimation of theophylline and montelukast

Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation. It is defined by the history of respiratory symptoms such as wheeze, shortness of breath, chest tightness and cough that vary over time and in intensity, together with variable expiratory airflow limitation. Liquid chromatography is a separation technique that involves the placement (injection) of a small volume of liquid sample into a tube packed with porous particles (stationary phase) where individual components of the sample are transported along the packed tube (column) by a liquid. HPLC is optimum for the separation of chemical and biological compounds that are non-volatile. This method are highly automated and extremely sensitive.In RP-HPLC, the column size is the same, but the silica is modified to make it non-polar by attaching long hydrocarbon chains to its surface - typically with either 8 or 18 carbon atoms in them. A polar solvent is used i.e. a mixture of water and an alcohol.