Oral Nanostructured Lipid Carriers Loaded with Near-Infrared Dye for Image-Guided Photothermal Therapy.

Photothermal therapy exerts its anticancer effect by converting laser radiation energy into hyperthermia using a suitable photosensitizer. This study reports development of nanostructured lipid carriers (NLCs) suitable for noninvasive oral delivery of a near-infrared photosensitizer dye IR780. The carrier encapsulating the dye (IR780@NLCs) was stable in simulated gastric and intestinal conditions and showed greatly enhanced oral absorption of IR780 when compared with the free dye. As a result of increased oral bioavailability, enhanced accumulation of the dye in subcutaneous mouse colon tumors (CT-26 cells) was observed following oral gavage of IR780@NLCs. Photothermal antitumor activity of orally administered IR780@NLCs was evaluated following local laser irradiation of the CT-26 tumors. We observed significant effect of the photothermal IR780@NLCs treatment on the rate of the tumor growth and no toxicity associated with the oral administration of IR780@NLCs. Overall, orally administered IR780@NLCs represents a safe and noninvasive method to achieve systemic tumor delivery of a photosensitizing dye for applications in photothermal anticancer therapies.