Potentiometric Method to Determine Montelukast Sodium in its Tablets with In-line Monitoring of its Dissolution Behaviour

Direct drug determination without any pervious treatment steps is the most environmentally friendly method of analysis. Traditional analysis methods usually involve a pre-treatment step before analysis and this consumes time and organic solvents. This work describes direct potentiometric method by using ion selective electrode to determine Montelukast Sodium in its pure drug substance and in tablet formulation and for inline monitoring of its release from its tablet form without any sample pretreatment. A Sensor was fabricated using PVC based membrane containing tetradodecyl ammonium bromide (TDB) being as an anionic exchanger and 2-nitrophenyl-octyl-ether (2-NPOE) being a plasticizer. The validation of the proposed method was done according to International unio‎n of pure and applied chemistry recommendations, in which the proposed sensor show a linear dynamic range from 1.0×10-6 to 1.0×10-2 mol/L. The proposed sensor was applied to determine Montelukast sodium in bulk powder, tablets dosage form with no extraction. The sensor was also used as bench-top real-time analyser for in process tracking of Montelukast sodium concentration during monitoring of its dissolution behaviour, under U.S. Food and Drug Administration dissolution regulations, with clear discrimination from its common excipients. Results obtained by the proposed potentiometric method were compared with those obtained by the official HPLC method.