Application of ion-pairs in pharmaceutical analysis, atomic absorption spectrometric determination of promazine, chlorpromazine, promethazine, imipramine and ciprofloxacin hydrochlorides with sodium cobaltinitrite

Ion-association complexes of promazine HCl (I), chlorpromazine HCl (II), pr omethazine HCl(III), imipramine HCl (IV) and ciprofloxacin HCl (V) with [Co (NO2)(o)](3-) were precipitated at their optimum conditions of pH and ionic strength (NaCl-HCl/NaOH) and the excess unreacted cobalt complex was deter mined using atomic absorption spectrometry (AAS). The applicability of the method for determination of the above drugs in pure solution, pharmaceutica l preparations and urine was examined. The drugs can be determined in the r anges 0.485-4.854, 1.619-16.197, 1.441-14.410, 1.415-14.154 and 0.578-5.787 mg/25 ml of I, II, III, IV and V, respectively, with mean relative standar d deviations 1.05-1.53% and recovery values of 98.85+/-0.31-100.09+/-0.54% indicating high precision and accuracy. The sensitivities of the proposed m ethod were 11.73, 23.00, 30.00, 38.00 and 12.69 mu g/ml for the drugs I, II , III, IV and V, respectively; and the detection limits for determination o f the investigated drugs were 3.10, 7.20, 13.80, 18.30 and 6.63 mu g/ml for I, II, III, IV and V, respectively. The suggested method has been applied for the determination of the above mentioned drugs in their pharmaceutical formulations and urine.