A Novel Analytical Method for Determining a Combination of Tetrahydrozoline and Antazoline HCl by Modulating Ratio Spectra

In this study, the combination of pharmaceutical formulation of tetrahydrozline HCl (TZ) and antazoline HCl (AN) was determined without separating them using smart analytical UV spectrophotometric methods. While the Extended Ratio Subtraction Method (EXRSM) is used to determine AN, the Ratio Subtraction Method (RSM) is utilized to determine TZ and is linked with the ratio subtraction technique. The calibration curves for AN and TZ are linear, ranging from 3.0 to 30.0 µg/mL and 5.0 to 45.0 µg/mL, respectively. Analyzing several laboratory-prepared combinations of the two medications allowed researchers to assess the specificity of the designed methods. The selected drugs' combined dosage form was determined with success using both approaches. Validation was carried out in accordance with ICH requirements, and it was found that repeatability, accuracy, and intermediate precision were all within acceptable limits. Statistical studies showed that both methods can be competitively applied in quality control laboratories. RSM and the EXRSM are complementary to one another, as shown by the determination of AN and TZ without pre-separation. Without any prior separation, the EXRSM was able to differentiate between substances with an extended spectrum using the same characteristics. Therefore, one alternative approach to liquid chromatography techniques is the combination of EXRSM and RSM.