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Graphical abstract Highlights • Silk fibroin nanoparticles with a diameter of 40 nm were prepared. • The nanoparticles were stable at 4, 32, and 37 °C for a week. • The nanoparticles penetrated the stratum corneum. • The nanoparticles were delivered to deep hair follicles, the epidermis, and the dermis. Abstract Transdermal administration of drugs improves their bioavailability and is capable of systemic and local treatment. To improve the skin permeability of drugs, nano-sized systems have attracted attention as drug carriers for transdermal drug delivery system. We considered that silk fibroin composed of a crystalline region with many hydrophobic amino acids and an amorphous region with many hydrophilic amino acids was useful as a carrier for transdermal administration of a drug because of the balance between hydrophilicity and hydrophobicity. In this study, silk fibroin nanoparticles with mean volume diameters of 42.3 nm were successfully prepared, and storage stability was confirmed by storing the nanoparticle suspension at 4, 32, and 37 °C for a week. At any storage temperature, the mean volume diameter and standard deviation were stable. The polydispersity indexes were 0.19–0.23, and no specific trends were observed. Then, to investigate the transdermal delivery route of the silk fibroin nanoparticles, skin permeability in vivo was evaluated using mice. Six hours after administration, fluorescent substances were observed in the dermis in addition to the stratum corneum, hair follicles and the epidermis around them. This result indicated that fibroin nanoparticles with the mean volume diameter of 40-nm penetrated the stratum corneum and was delivered deep into the skin. Therefore, it was suggested that small nanoparticles prepared using silk fibroin are useful for drug delivery to the dermis. [ABSTRACT FROM AUTHOR]

Abstract: Estradiol is a therapeutic agent for treatment of perimenopausal symptoms and osteoporosis. Conventional oral or intravenous administration of estradiol has many problems, such as, metabolization in gastrointestinal tract and liver, pain by using an injection needle, rapid increase of drug levels in blood and fast clearance with unwanted side effects including thrombosis, endometriosis and uterus carcinoma. The use of nanocarriers for transdermal delivery has been studied because of their ability to deliver therapeutic agents for long time with a controlled ratio, escaping from the first pass effect by liver. In this study, permeability of estradiol-loaded PLGA nanoparticles through rat skin was studied. Higher amount of estradiol was delivered through skin when estradiol was loaded in nanoparticles than estradiol was free molecules. Also, iontophoresis was applied to enhance the permeability of nanoparticles. When iontophoresis was applied, permeability of estradiol-loaded PLGA nanoparticles was much higher than that obtained by simple diffusion of them through skin, since they have negative surface charges. They were found to penetrate through follicles mainly. Also, enhanced permeability effect of estradiol by using nanoparticle system and iontophoresis were observed in vivo. The combination of charged nanoparticle system with iontophoresis is useful for effective transdermal delivery of therapeutic agents. [Copyright &y& Elsevier]

Abstract: Nanoparticles effectively deliver therapeutic agent by penetrating into the rat skin in vivo. Indomethacin (IM) and coumarin-6 were loaded in PLGA nanoparticles with an average diameter of 100nm. Indomethacin (IM) and coumarin-6 were chosen as a model drug and as a fluorescent marker, respectively. The surfaces of the nanoparticles were negatively charged. Permeability of IM-loaded PLGA nanoparticles through rat skin was studied in vivo. Higher amount of IM was delivered through skin when IM was loaded in nanoparticles than IM was free molecules. Also, iontophoresis was applied to enhance the permeability of nanoparticles. When iontophoresis was applied at 0.05mA/cm2, permeability of IM was much higher than that obtained by simple diffusion of nanoparticles through skin. The combination of charged nanoparticle system with iontophoresis is useful for effective transdermal systemic delivery of therapeutic agents. [Copyright &y& Elsevier]

Abstract: Nanoparticles effectively deliver therapeutic agent by penetrating into the skin. Indomethacin (IM) and coumarin-6 were loaded in PLGA nanoparticles with an average diameter of 100nm. IM and coumarin-6 were chosen as a model drug and as a fluorescent marker, respectively. The surfaces of the nanoparticles were negatively charged. Permeability of IM-loaded PLGA nanoparticles through rat skin was studied. Higher amount of IM was delivered through skin when IM was loaded in nanoparticles than IM was free molecules. Also, iontophoresis was applied to enhance the permeability of nanoparticles. When iontophoresis with 3V/cm was applied, permeability of IM was much higher than that obtained by simple diffusion of nanoparticles through skin. The combination of charged nanoparticle system with iontophoresis is useful for effective transdermal delivery of therapeutic agents. [Copyright &y& Elsevier]

Abstract: Nanoparticles have widely been studied in drug delivery research for targeting and controlled release. The aim of this article is application of nanoparticles as an inhalable agent for treatment of lung cancer. To deposit effectively deep the particles in the lungs, the PLGA nanoparticles loaded with the anticancer drug 6-{[2-(dimethylamino)ethyl]amino}-3-hydroxyl-7H-indeno[2,1-c]quinolin-7-one dihydrochloride (TAS-103) were prepared in the form of nanocomposite particles. The nanocomposite particles consist of the complex of drug-loaded nanoparticles and excipients. In this study, the anticancer effects of the nanocomposite particles against the lung cancer cell line A549. Also, the concentration of TAS-103 in blood and lungs were determined after administration of the nanocomposite particles by inhalation to rats. TAS-103-loaded PLGA nanoparticles were prepared with 5% and 10% of loading ratio by spray drying method with trehalose as an excipient. The 5% drug-loaded nanocomposite particles were more suitable for inhalable agent because of the sustained release of TAS-103 and higher FPF value. Cytotoxicity of nanocomposite particles against A549 cells was higher than that of free drug. When the nanocomposite particles were administered in rats by inhalation, drug concentration in lung was much higher than that in plasma. Furthermore, drug concentration in lungs administered by inhalation of nanocomposite particles was much higher than that after intravenous administration of free drug. From these results, the nanocomposite particle systems could be promising for treatment of lung cancer. [Copyright &y& Elsevier]

Abstract: Purpose of the present work was to study in vitro permeation of gold nanoparticles (NPs) through isolated rat skin and intestine. Another objective was to see the effect of particle size on permeation of the gold NP. Gold NP of 15nm, 102nm and 198nm were synthesized and used for study. Franz diffusion cells were used to evaluate permeation of gold NP from rat skin whereas ‘intestinal sac’ method was used for assessing intestinal permeation. Number density of gold NP was analyzed by UV–vis spectroscopy whereas amount of gold permeated was measured by ICP mass spectrometry. The absorption and localization of gold NP through rat skin was studied by TEM. Qualitative analysis of gold inside of the rat skin was performed by energy dispersive X-ray spectroscopy (EDS). Gold NP showed negative zeta potential. UV–vis absorption spectra of 15nm, 102nm and 198nm gold NP showed λ max at 520nm, 535nm and 577nm, respectively. SEM study revealed spherical morphology of NP. Gold NP showed size dependent permeation through rat skin and intestine. 15nm gold NP showed higher permeation compared to 102nm and 198nm gold NP. Interestingly, 102nm and 198nm gold NP showed lag time of 3h and 6h in case of rat skin only. As the size of the gold NP increased, permeability coefficient and diffusion coefficient was found to be decreased. The permeation of gold NP through intestine was higher than that of skin. TEM study of rat skin revealed accumulation of smaller size gold NP in deeper region of skin whereas larger particles were observed mainly in epidermis and dermis. Presence of gold inside of rat skin was confirmed by EDS. Gold NP would be an interesting carrier for transdermal as well as for oral delivery. The study demonstrated initial proof of concept of percutaneous permeation of smaller size gold particles. [Copyright &y& Elsevier]