Photodynamic and photothermal therapies with IR780 have gained exponential interest, and their photophysical properties have demonstrated promise for use in antitumor and antimicrobial chemotherapy. IR780 and its derivatives are valuable in labeling nanostructures with different chemical compositions for in vitro and in vivo fluorescence monitoring studies in the near-infrared (NIR) spectrum. The current literature is abundant on this topic, particularly with applications in the treatment of different types of cancer using laser illumination to produce photodynamic (PDT), photothermal (PTT), and, more recently, sonodynamic therapy (SDT) approaches for cell death. This review aims to update the state of the art concerning IR780 photosensitizer as a theranostic agent for PDT, PTT, SDT, and photoacoustic (PA) effects, and fluorescence imaging monitoring associated with different types of nanocarriers. The literature update concerns a period from 2017 to 2024, considering, more specifically, the in vivo effects found in preclinical experiments. Some aspects of the labeling stability of nanostructured systems will be discussed based on the evidence of IR780 leakage from the nanocarrier and its consequences for the reliable analysis of biological data.

Background: Combination chemotherapy using nanotechnology-based delivery is a promising approach to improve cancer treatment, but the added value of co-loaded polymeric nanocarriers has not been comprehensively appraised. This review synthesizes preclinical evidence on polymeric systems co-encapsulating antitumor agents. Methods: A narrative literature review identified 33 preclinical studies (2015–2025) employing polymer-based nanocarriers to co-load at least two antitumor drugs. Study characteristics and in vitro and in vivo outcomes were qualitatively analyzed. Results: Most studies addressed breast, lung, or ovarian cancer and used micelles or nanospheres. Co-loaded formulations consistently enhanced in vitro cytotoxicity and, in vivo, produced marked tumor growth inhibition relative to free drugs or single-loaded systems; in several reports, near-complete or complete tumor regression was achieved. Synergy was frequently suggested but not consistently quantified, more than half of the studies did not report a combination index. Most formulations showed favorable tolerability, with few reports including mild hepatic toxicity, renal, or weight-related effects. Beyond conventional drug pairs, examples of co-delivering chemotherapeutics with resistance modulators, gene therapy agents, or targeted ligands illustrated how tailored release profiles and active targeting can potentiate efficacy. Nevertheless, heterogeneity in models, dosing schedules, endpoints, and limited long-term safety data hamper cross-study comparison and translation. Conclusions: Co-loaded polymeric nanocarriers constitute a promising platform to optimize combination chemotherapy, improving preclinical antitumor efficacy with generally limited toxicity, but more standardized and mechanistically driven studies are required to support clinical development.