Amongst various drug administration methods, ophthalmic drug delivery has been a useful way for the treatment of eye-related diseases. However, therapeutic efficacy of ocular therapy for anterior or posterior eye segments through topical administration is considerably challenged by the number of anatomical and physiological barriers in the eyes affecting ocular bioavailability. In this respect, advanced biocompatible nanoformulations make it possible to improve drug delivery to the target sites and enhance ocular bioavailability of ophthalmic medicines. Various ocular diseases have been reported to be related to oxidative stresses in tissues, and polyphenolic compounds have been known for their antioxidant activities in various tissues, including the eyes. Despite drug efficacy, poor water solubility and intrinsic color of the compounds limit the drug’s inclusion into the development of ocular medicine. In the present study, we investigated the antioxidant protectant efficacy of rosmarinic or ursolic acid in the retinal epithelial cells, as compared to those of curcumin, by forming nanospheres with bovine serum albumin. Our results demonstrate that antioxidant-containing nanoformulations provide a significantly higher drug solubility and decreased ROS (reactive oxygen species) production in the retinal epithelial cells. Finally, we also found that albumin-based nanoformulations could improve bioavailability and increase antioxidant activity of rosmarinic or ursolic acid in the retina to be applied as efficient ocular protectant.

Iron oxide nanoparticle (IONP) possesses unique advantages over other nanoparticles in the use of cancer imaging and therapy. Specifically, it has drawn great attention in the emerging research field of photothermal cancer therapy. Herein, we developed doxorubicin (DOX)-loaded liposomal IONP (Lipo-IONP/DOX) and evaluated in vitro and in vivo their applicability for combined chemo-photothermal cancer therapy. The Lipo-IONP was synthesized by the thin-film evaporation method. The prepared Lipo-IONP was observed as about a 240 nm-sized agglomerate of globular-shaped nanoparticles. The TEM and FT-IR data evidenced the successful formation of liposomal IONP. The superparamagnetic property of the Lipo-IONP was confirmed by the SQUID analysis. The DSC data showed a transition temperature of about 47–48 °C for the mixed lipids composing the Lipo IONP, and the DOX release studies revealed the feasibility of induced burst release of DOX by laser irradiation. The Lipo-IONP/DOX possessed a plasma half-life of 42 min, which could ensure sufficient circulation time for magnetic tumor targeting. The in vivo magnetic targeting enabled a significant increase (6.3-fold) in the tumor accumulation of Lipo-IONP/DOX, leading to greater photothermal effects. Finally, the preliminary efficacy study evidenced the applicability as well as the safety of the Lipo-IONP/DOX for use in combined chemo-photothermal cancer therapy. Overall, the study results demonstrated that the Lipo-IONP/DOX might serve as an effective and safe agent for combined chemo-photothermal cancer therapy.

Iron oxide nanoparticles (IONPs) possess versatile utility in cancer theranostics, thus, they have drawn enormous interest in the cancer research field. Herein, we prepared polyethylene glycol (PEG)-conjugated and starch-coated IONPs (“PEG–starch–IONPs”), and assessed their applicability for photothermal treatment (PTT) of cancer. The prepared PEG–starch–IONPs were investigated for their physical properties by transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and dynamic light scattering (DLS). The pharmacokinetic study results showed a significant extension in the plasma half-life by PEGylation, which led to a markedly increased (5.7-fold) tumor accumulation. When PEG–starch–IONPs were evaluated for their photothermal activity, notably, they displayed marked and reproducible heating effects selectively on the tumor site with laser irradiation. Lastly, efficacy studies demonstrated that PEG–starch–IONPs-based PTT may be a promising mode of cancer therapy.

Toxin peptides derived from the skin secretions of amphibians possess unique hypoglycemic activities. Many of these peptides share cationic and amphipathic structural similarities and appear to possess cell-penetrating abilities. The mechanism of their insulinotropic action is yet not elucidated, but they have shown great potential in regulating the blood glucose levels in animal models. Therefore, they have emerged as potential drug candidates as therapeutics for type 2 diabetes. Despite their anti-diabetic activity, there remain pharmaceutical challenges to be addressed for their clinical applications. Here, we present an overview of recent studies related to the toxin-derived anti-diabetic peptides derived from the skin secretions of amphibians. In the latter part, we introduce the bottleneck challenges for their delivery in vivo and general drug delivery strategies that may be applicable to extend their blood circulation time. We focus our research on the strategies that have been successfully applied to improve the plasma half-life of exendin-4, a clinically available toxin-derived anti-diabetic peptide drug.