On degree-dependent topological study of line graph of some antiviral COVID-19 drugs.

A topological index is a numerical value that correlates with a chemical structure. A degree-based topological index of drug molecular structures is beneficial for researchers investigating in the fields of medicals and pharmaceuticals because it is significant for testing the physicochemical properties of drugs. Graph theory has proven to be quite useful in this field of study. Graph analysis reveals insights into chemical structures. In physical chemistry, a line graph has multiple applications. This article focuses on the topological characterization of a line graph for antiviral COVID-19 drugs, namely Nirmatrelvir, Molnupiravir, Thalidomide, Theaflavin, Remdesivir, Ritonavir, Chloroquine, Hydroxychloroquine, Arbidol and Lopinavir. The computation of degree-based topological indices is carried out using their M-polynomials. Numerical values of topological indices of line graphs and geometric representations of the polynomials are shown graphically. A comparative study between the obtained values of the line graph and the values of an actual graph is presented through numerical and graphical representation. Furthermore, we conduct a QSPR analysis between the degree-based topological indices of the line graph of certain COVID-19 drugs and their physicochemical properties using curvilinear regression models. A comparison is made between the squared correlation coefficients derived from our curvilinear regression models and those obtained from earlier research. These findings may aid the applicability of newly developed drugs of similar kind, in predicting their physicochemical properties and in improving the associated QSPR studies and hence pave a way to improve treatments against the COVID-19 disease.