Development of Rp-HPLC method for fexofenadine determination in tablet formulations and development of dissolution method

Fexofenadine hydrochloride is a piperidine derivative. It is indicated to relive signs and symptoms that are related with seasonal allergic rhinitis, such as rhinorrhea, sneezing, nose, throat and itchy eyes. In the present research work a liquid chromatographic method was developed for the determination of Fexofenadine in tablets and the dissolution method by UV/VIS spectrophotometer was also developed. Method was developed by using Lichrospher 10 micro m [C18] column. The mobile phase is composed of acetonitrile-5mM ammonium acetate buffer [50:50, v/v] pumped at a flow rate of 1 ml/min. The UV detector was operated at 254nm. The method was validated for system suitability, accuracy/recovery, linearity, system precision, method precision, ruggedness, robustness, limit of detection and limit of quantitation. Similarly, for dissolution method difference concentrations of standard and sample solutions were prepared i.e. 65 micro g/ml, 35 micro g/ml, 17.5 micro g/ml, 8.75 micro g/ml and 4.375 micro g/ml. The proposed HPLC method was easy, precise and fewer time consuming. The linearity for the dissolution method was found to be acceptable. The correlation coefficient of standard solutions was 0.9979 similarly the correlation coefficient of sample solutions was 0.9963

First derivative spectrophotometric determination of weakly UV absorbing terfenadine and bencyclane

Rapid first derivative procedure is described for the determination of terfenadine and bencyclane in pure samples and in dosage forms. The method is based on the reaction of these drugs as n-electron donors with picric acid as ceta-acceptor, to form stable charge-transfer [CT] complexes. The coloured products are quantified by measuring the first derivative [D[1]] peak amplitude at 430 nm and at 425nm for terfenadine and bencyclane, respectively, or the peak-trough amplitude at 360-325 nm for terfenadine. Beer's law is obeyed over the concetration range 4-20 micro g ml[-1] of the investigated drugs. The proposed method is simple and sensitive. Reproducible, accurate and reliable results were obtained. The results were statistically compared with those of the standard methods. Terfenadine, alpha-[4-[1,1-dimethylethyl] phenyl]-4- [hydroxydiphenylmethyl] -1- piperidinebutanol, is a selective histamine H[1]-receptor antagonist used to relieve the symptoms of allergy. Bencyclane, N,N-dimethyl -3- [[1-[phenylmethyl]-cycloheptyl] oxy]-1-propanamine, is vasodilator which has been given in the treatment of peripheral and cerebral vascular disorders. Terfenadine and bencyclane are weakly UV absorbing compounds. Their [E 1%] ranged from 14.3-14.5 [1]. Therefore, the application of simple spectrophotometric methods is subjected to serious positive system error. To overcome this problem, many techniques have been reported [2-8]. Picric acid has been proved to be valuable reagent for the determination of some basic compounds [9,10]. Terfenadine and bencyclane have been also determined spectrophotometrically [11-15], coulometrically [16], GLC [17-20], HPLC [21,22] and radioimmunoassay [23.25]. This paper describes the application of the seta-acceptor picric acid [26] to the first derivative spectrophotometric determination of terfenadine and bencyclane as n-electron donors, in pure samples and in dosage forms