Determination of Metformine Hydrochloride Drug by Fabricated Selective Membrane Electrodes and High Performance Liquid Chromatography Method (HPLC)


First part : This part includes the determination of metformin.HCl (MET) by construction of two ion selective electrodes incorporating PVC membrane with phosphomolybdic acid (PM) or phosphotungstic acid (PT) as active materials. The plasticizer used is either Di-n-butyl phthalate (DBP) or Tri-n-butyl phosphate (TBP).The results for the electrodes are as follows:1-The linear range for (DBP-MET-PM) electrode was 10-5 – 10-1 M with a slope of 30.7 mV/decade and correlation coefficient of 0.9978. The limit of detection was 2.5 x 10-7 M and the optimum pH was in the range 3.6 – 4.2 at 25oC at the optimum concentration for the internal filling solution of 10-4 M . The life time for the electrode was 24 days.2-For (TBP-MET-PT), the linear concentration range was10-5–10-1 M with a slope of 30.8 mV/decade and a correlation coefficient of 0.9844. The limit of detection was 2.75 x 10-7 M at optimum pH range (4.2 – 4.6) at 10-4 M for internal filling solution. The life time of this electrode was 14 days .Second part : In this part , MET drug was determined by HPLC using C18 column. In this method and at pH= 3 using a mobile phase of ammonium dihydrogen phosphate with acetonitrile in a ratio of (50:2.5) and flow rate of 1 ml. minute, the MET drug was determined. The signal was detected at 233 nm. The percent recovery, relative standard deviation and the linearity of concentration were 98.14 %, 0.98 and 2-24 µ, respectively with a limit of detection of 0.23 µ .