Assessing the in vivo Safety of Dendrimer-Based Formulations Used in Photodynamic Therapy.

Introduction: Photodynamic therapy (PDT) is a promising cancer treatment. However, the efficacy of photosensitizers such as rose bengal (RB) is often limited by poor delivery. Dendrimer-based nanocarriers can enhance PDT efficacy in vitro, but their in vivo safety profile remains largely uncharacterized. This study aimed to assess the systemic safety of three different dendrimer-based RB delivery systems in a healthy mouse model. Methods: BALB/c mice were randomly divided into eight groups and received weekly intraperitoneal injections of either PBS (control), free RB, or one of three carriers (phosphorus dendrimer 1cat, dendrimersome DG2, PPI G3 dendrimer) with or without RB. Body weight was monitored weekly. Blood and urine samples were collected over four weeks for comprehensive biochemical and microscopic analysis, assessing markers for liver, kidney, and muscle function. Results: No significant changes in body weight were observed across any of the groups. Analysis of blood biochemical parameters (including ALT, AST, urea, creatinine, and LDH) and urine profiles revealed no statistically significant differences between any treatment group and the PBS control group over the four-week study period. The observed minor fluctuations in some parameters were not dose- or time-dependent and remained within normal physiological ranges. Conclusion: The three tested nanocarrier systems - phosphorus dendrimer 1cat, dendrimersome DG2, and PPI G3 dendrimer - and their respective rose bengal formulations are well tolerated and do not induce systemic toxicity in BALB/c mice at the tested concentrations. These findings support their safety for in vivo applications and provide a basis for future efficacy studies in tumor-bearing animal models.