Skin Cancer Treatment with Subcutaneous Delivery of Doxorubicin-Loaded Gelatin Nanoparticles and NIR Activation

Subcutaneous (SC) administration of chemotherapeutics combined with near-infrared (NIR) light activation can effectively target skin tumors by triggering localized drug release and enhancing cytotoxic effects. In this study, we developed NIR-responsive indocyanine green (ICG) and the chemotherapeutic agent doxorubicin (Dox) loaded into gelatin nanoparticles (NPs) for SC delivery in a skin tumor-bearing mouse model. Histological examination (hematoxylin and eosin staining) confirmed the successful delivery and swelling behavior of the Dox/ICG-loaded gelatin NPs at the SC site. In vitro and in vivo experiments demonstrated that NIR activation of the Dox/ICG-loaded gelatin NPs generated significant photothermal heat (48 and 46 °C), leading to targeted drug release and a substantial reduction in skin tumor size (from 15 to 3 mm3). Our findings suggest that this dual-modality approach of SC chemotherapeutic administration and NIR-triggered photothermal therapy can concentrate cytotoxic drugs at the tumor site, offering a promising strategy for improving skin cancer treatment.

Prospects of Delivering Natural Compounds by Polymer-Drug Conjugates in Cancer Therapeutics

Synthetic chemotherapeutics have played a crucial role in minimizing mostly palliative symptoms associated with cancer; however, they have also created other problems such as system toxicity due to a lack of specificity. This has led to the development of polymer-drug conjugates amongst other novel drug delivery systems. Most of the formulations designed using delivery systems consist of synthetic drugs and face issues such as drug resistance, which has already rendered drugs such as antibiotics ineffective. This is further exacerbated by toxicity due to long term use. Given these problems and the fact that conjugation of synthetic compounds to polymers has been relatively slow with no formulation on the market after a decade of extensive studies, the focus has shifted to using this platform with medicinal plant extracts to improve solubility, specificity and increase drug release of medicinal and herbal bioactives. In recent years, various plant extracts such as flavonoids, tannins and terpenoids have been studied extensively using this approach. The success of formulations developed using novel drug-delivery systems is highly dependent on the tumour microenvironment especially on the enhanced permeability and retention effect. As a result, the compromised lymphatic network and 'leaky' vasculature exhibited by tumour cells act as a guiding principle in the delivering of these formulations. This review focuses on the state of the polymer-drug conjugates and their exploration with natural compounds, the progress and difficulties thus far, and future directions concerning cancer treatment.