Predicting drug-target interactions (DTI) is critical for advancing drug discovery. However, existing DTI approaches struggle with data imbalance and heterogeneous information. This study presents a novel framework called PDGCL-DTI, which leverages two graph contrastive learning frameworks in parallel to capture both local and global features from drug-target heterogeneous networks. First, PDGCL-DTI effectively handles data imbalance through the AdaL-GCL module, which dynamically adjusts the weights of minority class samples to mitigate the impact of the imbalance. Second, by combining local and global contrastive learning, it extracts features from both local node information and global structural information, improving its adaptability to complex heterogeneous networks. This dual strategy enables PDGCL-DTI to exhibit greater robustness and higher prediction accuracy when handling complex DTI data. Experimental results on the ChEMBL, DrugBank, and DAVIS datasets show that PDGCL-DTI outperforms existing DTI methods, achieving an average AUC of 0.958 and an average accuracy of 0.95 across the three datasets. Additionally, case studies demonstrate that PDGCL-DTI successfully predicts interactions between Enasidenib and GABA-AT, as well as Sorafenib and Caspase-3, underscoring its practical applicability in the visualization workflow on the ChEMBL dataset.
