Application of derivative and ratio spectra derivative spectrophotometry for the determination of pseudoephedrine hydrochloride and acrivastine in capsules

Two new spectrophotometric methods are used for the determination of acrivastine and pseudoephedrine hydochloride in their mixture without previous chemical separation. In the first, second derivative spectrophotometry, the measurements are made at 288.0 nm for acrivastine and at 270.2 nm for pseudoephedrine hydrochloride in the second derivative spectra of their solution in 0.1M NaOH. In the second, ratio spectra derivative spectrophotometry, the amplitudes are measured at 276.0 nm and 298.5 nm corresponding to two maximums. for acrivastine, and at 252.6 nm and 268.3 nn corresponding to a maximum and a minumum, respectively, for pseudoephedrine hydrochloride in first derivative of their ratio spectra plotted by using of their solutions as divisor. The methods were successfully applied for the determination of these drugs in a commercial pharmaceutical formulation capsule.