1：Experimental Design and Method Selection:

The study utilized a first derivative synchronous spectrofluorimetric method for the determination of DCV in presence of its degradation products. The method was chosen for its sensitivity, simplicity, and rapidity.

2：Sample Selection and Data Sources:

DCV was subjected to oxidative and photolytic degradation. The samples were prepared from pharmaceutical tablets and pure drug powder.

3：List of Experimental Equipment and Materials:

A FP-8200 JASCO Spectrofluorophotometer, UV-1800 Shimadzu UV spectrophotometer, Seven2Go S2. -Basic; pH/mV portable meter, VILBER LOURMAT UV-lamp, and an ultrasonic bath were used. Materials included DCV dihydrochloride, methanol, acetonitrile, and various buffers.

4：-Basic; pH/mV portable meter, VILBER LOURMAT UV-lamp, and an ultrasonic bath were used. Materials included DCV dihydrochloride, methanol, acetonitrile, and various buffers. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The method involved scanning synchronous fluorescence at Δ λ of 80 nm, with measurements taken at 373 nm for oxidative degradation and 388 nm for photolytic degradation. The method was validated for linearity, accuracy, precision, specificity, and robustness.

5：Data Analysis Methods:

The data were analyzed using linear regression analysis to determine the correlation coefficient, standard deviation of residuals, and limits of detection and quantification.