Low molecular weight protamine-functionalized nanoparticles for drug delivery to the brain after intranasal administration

Alpha-tocopheryl polyethylene glycol succinate-emulsified poly(lactic-co-glycolic acid) nanoparticles for reversal of multidrug resistance in vitro

Multidrug resistance (MDR) is one of the factors in the failure of anticancer chemotherapy. In order to enhance the anticancer effect of P-glycoprotein (P-gp) substrates, inhibition of the P-gp efflux pump on MDR cells is a good tactic. We designed novel multifunctional drug-loaded alpha-tocopheryl polyethylene glycol succinate (TPGS)/poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TPGS/PLGA/SN-38 NPs; SN-38 is 7-ethyl-10-hydroxy-camptothecin), with TPGS-emulsified PLGA NPs as the carrier and modulator of the P-gp efflux pump and SN-38 as the model drug. TPGS/PLGA/SN-38 NPs were prepared using a modified solvent extraction/evaporation method. Physicochemical characterizations of TPGS/PLGA/SN-38 NPs were in conformity with the principle of nano-drug delivery systems (nDDSs), including a diameter of about 200 nm, excellent spherical particles with a smooth surface, narrow size distribution, appropriate surface charge, and successful drug-loading into the NPs. The cytotoxicity of TPGS/PLGA/SN-38 NPs to MDR cells was increased by 3.56 times compared with that of free SN-38. Based on an intracellular accumulation study relative to the time-dependent uptake and efflux inhibition, we suggest novel mechanisms of MDR reversal of TPGS/PLGA NPs. Firstly, TPGS/PLGA/SN-38 NPs improved the uptake of the loaded drug by clathrin-mediated endocytosis in the form of unbroken NPs. Simultaneously, intracellular NPs escaped the recognition of P-gp by MDR cells. After SN-38 was released from TPGS/PLGA/SN-38 NPs in MDR cells, TPGS or/and PLGA may modulate the efflux microenvironment of the P-gp pump, such as mitochondria and the P-gp domain with an ATP-binding site. Finally, the controlled-release drug entered the nucleus of the MDR cell to induce cytotoxicity. The present study showed that TPGS-emulsified PLGA NPs could be functional carriers in nDDS for anticancer drugs that are also P-gp substrates. More importantly, to enhance the therapeutic effect of P-gp substrates, this work might provide a new insight into the design of pharmacologically inactive excipients that can serve as P-gp modulators instead of drugs that are P-gp inhibitors.

Surface modification of amorphous nanosilica particles suppresses nanosilica-induced cytotoxicity, ROS generation, and DNA damage in various mammalian cells

Recently, nanomaterials have been utilized in various fields. In particular, amorphous nanosilica particles are increasingly being used in a range of applications, including cosmetics, food technology, and medical diagnostics. However, there is concern that the unique characteristics of nanomaterials might induce undesirable effects. The roles played by the physical characteristics of nanomaterials in cellular responses have not yet been elucidated precisely. Here, by using nanosilica particles (nSPs) with a diameter of 70nm whose surface was either unmodified (nSP70) or modified with amine (nSP70-N) or carboxyl groups (nSP70-C), we examined the relationship between the surface properties of nSPs and cellular responses such as cytotoxicity, reactive oxygen species (ROS) generation, and DNA damage. To compare the cytotoxicity of nSP70, nSP70-N, or nSP70-C, we examined in vitro cell viability after nSP treatment. Although the susceptibility of each cell line to the nSPs was different, nSP70-C and nSP70-N showed lower cytotoxicity than nSP70 in all cell lines. Furthermore, the generation of ROS and induction of DNA damage in nSP70-C- and nSP70-N-treated cells were lower than those in nSP70-treated cells. These results suggest that the surface properties of nSP70 play an important role in determining its safety, and surface modification of nSP70 with amine or carboxyl groups may be useful for the development of safer nSPs. We hope that our results will contribute to the development of safer nanomaterials.

Formulation and evaluation of microemulsion-based in situ ion-sensitive gelling systems for intranasal administration of curcumin

The purpose of our study was to develop a microemulsion-based in situ ion-sensitive gelling system for intranasal administration of curcumin. A new microemulsion composition for curcumin was optimized with the simple lattice design. And the microemulsion-based in situ ion-sensitive gelling system consisted of Capryol 90 as oil phase, Solutol HS15 as surfactant, Transcutol HP as cosurfactant and 0.3% DGG solution as water phase. The physicochemical properties such as morphology, droplet size distribution, zeta value and the in vitro release were investigated. In addition, the histological section studies on the reaction between the obtained formulation and nasal mucosa showed that the microemulsion-based in situ ion-sensitive gelling system could not produce obvious damage to nasal mucosa. The pharmacokinetics results showed that the absolute bioavailability of curcumin in the microemulsion-based in situ ion-sensitive gelling system was 55.82% by intranasal administration. And the brain targeting index (BTI) was 6.50, and in the tissue distribution experiment, the value of (AUC(brain)/AUC(blood)) following intranasal administration was higher than that following intravenous administration, suggesting that the obvious brain targeting property by nasal delivery be attributed to a direct nose-to-brain drug transport. It can be concluded that the microemulsion-based in situ gelling as an effective and safe vehicle could greatly enhance the in vivo absorption and facilitate the delivery of curcumin to brain by intranasal administration.

Nanocomposites for Neurodegenerative Diseases: Hydrogel-Nanoparticle Combinations for a Challenging Drug Delivery

Neurodegenerative disorders are expected to strike social and health care systems of developed countries heavily in the coming decades. Alzheimer's and Parkinson's diseases (AD/PD) are the most prevalent neurodegenerative pathologies, and currently their available therapy is only symptomatic. However, innovative potential drugs are actively under development, though their efficacy is sometimes limited by poor brain bioavailability and/or sustained peripheral degradation. To partly overcome these constraints, the development of drug delivery devices made by biocompatible and easily administrable materials might be a great adjuvant. In particular, materials science can provide a powerful tool to design hydrogels and nanoparticles as basic components of more complex nanocomposites that might ameliorate drug or cell delivery in AD/PD. This kind of approach is particularly promising for intranasal delivery, which might increase brain targeting of neuroprotective molecules or proteins. Here we review these issues, with a focus on nanoparticles as nanocomponents able to carry and tune drug release in the central nervous system, without ignoring warnings concerning their potential toxicity.