Author(s): MadihaHassanSoliman1*and EmanAbdelMoety
Three simple, accurate and precise methods were developed for determination of fenoterol HBr I, salbutamol sulphate II and theophylline III in pure forms and in pharmaceutical preparations. Thefirst method based on ion-pair formation between I, II and hematoxylin in alkaline medium pH 9.5 to give a stable colored product that showed maximum absorption at 559 nm. The linearity range was found to be 20-100 and 15-100 μg/ml for I and II respectively with recovery found to be 99.1 and 99.1for I and II respectively. Sandle sensitivity found to be and 0.44 μg/cm2for I and II respectively. The second one was TLC scanning method for I and II using silica gel plates in Ethyl acetate: Methanol and Ammonia (26:4:1) and the spots was measured by densitometer at 280 nm for both drugs. The limits of Beer’s law was 5-40 and 5-50 μg/spot in case of I and II respectively. Recovery found to be 101.12±1.17 and 100.20±1.10 for I and II respectively. The third method was separated by HPLC for II and III using Lidocaine as internal standard and Luna 5-CN 150X4.6 mm column, the mobile phase was (0.1% Heptane sulphonic acid soudium salt + 0.1ml triethylamine + 1 ml glacial acetic acid): Methanol (35: 65 v/v) and detected by UV/Visible spectrometric at 244 nm. The liner relationship between area under beaks and concentration was given over a range from 20-400 and10-100 μg/ml for drugs II and III respectively. The three methods were successfully applied on the raw materials and in pharmaceutical preparations.