In the current context of viral variability driven by their high mutability, comprehensive measures for prevention, control, and treatment with effective antiviral agents are required, along with the development of rapid and reliable methods for quality control. This work is based on an approach employing the kinetics of diffuse light reflection (DLR) from a rough surface, followed by chemometric processing of dynamic speckle patterns. To this end, mathematical descriptors analogous to QSAR models were incorporated into the calculation algorithm: Wiener (W) and Balaban (J) indices in the Trinaystich modification—d1, d2, d3—as well as two triads of root-mean-square deviations sd1, sd2, sd3; r1, r2, r3 (where ri=di/sdi) and . The aim of the study was to develop and validate an analytical method based on 2D-DLR for the quantitative assessment of antiviral drug substances. Materials and Methods. Ribavirin (manufacturer Jiangling Benda Pharmaceutical Co., China) — a synthetic nucleoside analog with prominent antiviral activity and antimetabolic properties; model aqueous solutions (concentrations ranging from 0.25 mg/mL to 5 mg/mL), n=6n=6; proprietary software (Vidan®). Results. A family of 10 descriptors, represented as sequential horizontal bands on the 2D diagram (with didi corresponding to concentration, µg/mL), demonstrated stability of values for a specific sample within intra-laboratory reproducibility, and differentiation among samples with different solution dilutions. Particularly illustrative and statistically significant was the result for the topological descriptor R (correlation coefficient r=0.9998). This enabled the construction of a calibration curve in the coordinates “R-concentration (µg/mL),” based on the linear equation y=170.4+55.7⋅xy=170.4+55.7⋅x, with r=0.982. The method was validated according to ICH Q2 (R1) guidelines, confirming linearity, accuracy (RSD = 7.19%), and repeatability (n=6, P=0.95). The repeatability error (εε) was determined to be 7.55%, indicating acceptable analytical variability. Conclusion. The 2D-DLR method demonstrated reliability for systematic quantification of concentration of the antiviral ribavirin in aqueous solutions.