Reciprocal competition between lipid nanocapsules and P-gp for paclitaxel transport across Caco-2 cells

Brain targeted lactoferrin coated lipid nanocapsules for the combined effects of apocynin and lavender essential oil in PTZ induced seizures

Apocynin (APO) is a plant derived antioxidant exerting specific NADPH oxidase inhibitory action substantiating its neuroprotective effects in various CNS disorders, including epilepsy. Due to rapid elimination and poor bioavailability, treatment with APO is challenging. Correspondingly, novel APO-loaded lipid nanocapsules (APO-LNC) were formulated and coated with lactoferrin (LF-APO-LNC) to improve br ain targetability and prolong residence time. Lavender oil (LAV) was incorporated into LNC as a bioactive ingredient to act synergistically with APO in alleviating pentylenetetrazol (PTZ)-induced seizures. The optimized LF-APO-LAV/LNC showed a particle size 59.7 ± 4.5 nm with narrow distribution and 6.07 ± 1.6mV zeta potential) with high entrapment efficiency 92 ± 2.4% and sustained release (35% in 72 h). Following subcutaneous administration, LF-APO-LAV/LNC brought about ⁓twofold increase in plasma AUC and MRT compared to APO. A Log BB value of 0.2 ± 0.14 at 90 min reflects increased brain accumulation. In a PTZ-induced seizures rat model, LF-APO-LAV/LNC showed a Modified Racine score of 0.67 ± 0.47 with a significant increase in seizures latency and decrease in duration. Moreover, oxidant/antioxidant capacity and inflammatory markers levels in brain tissue were significantly improved. Histopathological and immunohistochemical assessment of brain tissue sections further supported these findings. The results suggest APO/LAV combination in LF-coated LNC as a promising approach to counteract seizures.

Innovative drug delivery strategies to the CNS for the treatment of multiple sclerosis

Disorders of the central nervous system (CNS), such as multiple sclerosis (MS) represent a great emotional, financial and social burden. Despite intense efforts, great unmet medical needs remain in that field. MS is an autoimmune, chronic inflammatory demyelinating disease with no curative treatment up to date. The current therapies mostly act in the periphery and seek to modulate aberrant immune responses as well as slow down the progression of the disease. Some of these therapies are associated with adverse effects related partly to their administration route and show some limitations due to their rapid clearance and inability to reach the CNS. The scientific community have recently focused their research on developing MS therapies targeting different processes within the CNS. However, delivery of therapeutics to the CNS is mainly limited by the presence of the blood-brain barrier (BBB). Therefore, there is a pressing need to develop new drug delivery strategies that ensure CNS availability to capitalize on identified therapeutic targets. Several approaches have been developed to overcome or bypass the BBB and increase delivery of therapeutics to the CNS. Among these strategies, the use of alternative routes of administration, such as the nose-to-brain (N2B) pathway, offers a promising non-invasive option in the scope of MS, as it would allow a direct transport of the drugs from the nasal cavity to the brain. Moreover, the combination of bioactive molecules within nanocarriers bring forth new opportunities for MS therapies, allowing and/or increasing their transport to the CNS. Here we will review and discuss these alternative administration routes as well as the nanocarrier approaches useful to deliver drugs for MS.

Enhancing the stability, BBB permeability and neuroprotective activity of verbascoside in vitro using lipid nanocapsules in combination with menthol

Verbascoside (VER) shows promising neuroprotective activity. However, the instability and low permeability in crossing the blood-brain barrier (BBB) greatly hinder its application. In the present study, verbascoside was encapsulated into lipid nanocapsules (LNC) by reverse micelle (RM) to increase its stability. Besides, we used VER-RM-LNC combined with an envoy drug, menthol, to improve its BBB permeability and neuroprotective activity. VER-RM-LNC was prepared by the phase inversion temperature method, resulting in an encapsulation efficiency of nearly 85 %. The formulated VER-RM-LNC was stable for 6 months at 4 °C. VER encapsulated into LNC possessed enhanced stability and a reduced release profile. Menthol increased the cellular uptake and the permeability of VER-RM-LNC in the BBB model in vitro. In addition, the improved neuroprotective activity of VER through incubation with menthol and VER-RM-LNC was verified in the neurotoxic human brain microvascular endothelial cells model induced by Aβ_25-35.

Enhanced anti-tumor activity of a drug through pH-triggered release and dual targeting by calcium phosphate-covered mesoporous silica vehicles

Rapid release and clearance of antitumor drugs in vivo are the main factors used to evade the effectiveness of chemotherapeutics. Targeted delivery and controlled release of drugs are the most pressing dilemmas in cancer therapy. Herein we report the design and fabrication of multifunctional mesoporous silica nanoparticles coated with poly(N-isopropylacrylamide)-co-acrylic acid and calcium phosphate (MSCNs) with pH-triggered chemotherapeutic release and dual-targeting functions. By decorating the nanoparticle surface with a transferrin (Tf)/RGD ligand, these nanoparticles are capable of not only recognizing the intrinsic pH difference between tumor and normal tissues, but also targeting the lesion location. It was shown that Tf/RGD-MSCNs delivered the anti-tumor drug doxorubicin more efficiently into lysosomes and the resulting DOX-loaded nanoparticles (DOX-Tf/RGD-MSCNs) showed a stronger inhibitory effect towards tumor cell growth than free DOX and DOX delivered by unmodified MSNs. Moreover, the nanoparticles are more biocompatible than uncoated mesoporous silica nanoparticles. All these results indicate that Tf/RGD-MSCNs have great potential as a novel drug carrier in therapeutic applications against cancers.

Active Targeted Nanoemulsions for Repurposing of Tegaserod in Alzheimer's Disease Treatment

Background and Purpose: The activation of 5-HT₄ receptors with agonists has emerged as a valuable therapeutic strategy to treat Alzheimer’s disease (AD) by enhancing the nonamyloidogenic pathway. Here, the potential therapeutic effects of tegaserod, an effective agent for irritable bowel syndrome, were assessed for AD treatment. To envisage its efficient repurposing, tegaserod-loaded nanoemulsions were developed and functionalized by a blood–brain barrier shuttle peptide. Results: The butyrylcholinesterase inhibitory activity of tegaserod and its neuroprotective cellular effects were highlighted, confirming the interest of this pleiotropic drug for AD treatment. In regard to its drugability profile, and in order to limit its peripheral distribution after IV administration, its encapsulation into monodisperse lipid nanoemulsions (Tg-NEs) of about 50 nm, and with neutral zeta potential characteristics, was performed. The stability of the formulation in stock conditions at 4 °C and in blood biomimetic medium was established. The adsorption on Tg-NEs of peptide-22 was realized. The functionalized NEs were characterized by chromatographic methods (SEC and C₁₈/HPLC) and isothermal titration calorimetry, attesting the efficiency of the adsorption. From in vitro assays, these nanocarriers appeared suitable for enabling tegaserod controlled release without hemolytic properties. Conclusion: The developed peptide-22 functionalized Tg-NEs appear as a valuable tool to allow exploration of the repurposed tegaserod in AD treatment in further preclinical studies.

Study on the Inhibitory Effects of Naringenin-Loaded Nanostructured Lipid Carriers Against Nonalcoholic Fatty Liver Disease

Naringenin (NGN) can be used to inhibit the progression of nonalcoholic fatty liver disease (NAFLD) in mice, but its poor water solubility limits its applications. Nanostructured lipid carriers (NLCs) have recently attracted much attention in the field of nanodrug delivery systems because they increase the drug loading capacity and impressively enhance the solubility of indissolvable drugs. Herein, a thin-film dispersion method was used to prepare naringenin-loaded nanostructured lipid carriers (NGN-NLCs). These NGN-NLCs have a narrow size distribution of 171.9 ±2.0 nm, a high drug loading capacity of 23.7 ± 0.3%, a high encapsulation efficiency of 99.9 ± 0.0% and a drug release rate of 86.2 ± 0.4%. NGN- NLCs elevated the pharmacokinetic parameters (C_max and AUC_0→t) of NGN, accelerated NGN transepithelial transport in MDCK cells and intestinal absorption in the jejunum and ileum, and reduced hepatic lipid accumulation in an oleic acid (OA) plus lipopolysaccharide (LPS)-induced lipid deposition cell model in primary hepatocytes and in a methionine/choline deficient (MCD) diet-induced NAFLD mouse model. A detailed study of the mechanism showed that this NLC formulation elevated the drug release rate in simulated intestinal solutions in vitro, the transepithelial transport in MDCK cells, the oral absorption in mice and the ex vivo intestinal absorption of NGN. Thus, NGN-NLCs significantly enhanced the inhibitory effects of NGN on MCD diet induced mouse NAFLD.

Characterization of P-Glycoprotein Inhibitors for Evaluating the Effect of P-Glycoprotein on the Intestinal Absorption of Drugs

For developing oral drugs, it is necessary to predict the oral absorption of new chemical entities accurately. However, it is difficult because of the involvement of efflux transporters, including P-glycoprotein (P-gp), in their absorption process. In this study, we conducted a comparative analysis on the inhibitory activities of seven P-gp inhibitors (cyclosporin A, GF120918, LY335979, XR9576, WK-X-34, VX-710, and OC144-093) to evaluate the effect of P-gp on drug absorption. GF120918, LY335979, and XR9576 significantly decreased the basal-to-apical transport of paclitaxel, a P-gp substrate, across Caco-2 cell monolayers. GF120918 also inhibited the basal-to-apical transport of mitoxantrone, a breast cancer resistance protein (BCRP) substrate, in Caco-2 cells, whereas LY335979 hardly affected the mitoxantrone transport. In addition, the absorption rate of paclitaxel after oral administration in wild-type mice was significantly increased by pretreatment with LY335979, and it was similar to that in mdr1a/1b knockout mice. Moreover, the absorption rate of topotecan, a BCRP substrate, in wild-type mice pretreated with LY335979 was similar to that in mdr1a/1b knockout mice but significantly lower than that in bcrp knockout mice. These results indicate that LY335979 has a selective inhibitory activity for P-gp, and would be useful for evaluating the contribution of P-gp to drug absorption.

Mechanism of cellular uptake and cytotoxicity of paclitaxel loaded lipid nanocapsules in breast cancer cells

Lipid nanocapsules (LNCs) have proven their efficacy in delivering different drugs to various cancers, but no studies have yet described their uptake mechanisms, paclitaxel (PTX) delivery or resulting cytotoxicity towards breast cancer cells. Herein, we report results concerning cellular uptake of LNCs and cytotoxicity studies of PTX-loaded LNCs (LNCs-PTX) on the three breast cancer cell lines MCF-7, MDA-MB-231 and MDA-MB-468. LNCs-PTX of sizes 50 ± 2 nm, 90 ± 3 nm and 120 ± 4 nm were developed by the phase inversion method. Fluorescence microscopy and flow cytometry were used to observe the uptake of fluorescently labeled LNCs and cellular uptake of LNCs-PTX was measured using HPLC analyses of cell samples. These studies revealed a higher uptake of LNCs-PTX in MDA-MB-468 cells than in the other two cell lines. Moreover, free PTX and LNCs-PTX exhibited a similar pattern of toxicity towards each cell line, but MDA-MB-468 cells appeared to be more sensitive than the other two cell lines, as evaluated by the MTT cytotoxicity assay and a cell proliferation assay based upon [³H]thymidine incorporation. Studies with inhibitors of endocytosis indicate that the cellular uptake is mainly via the Cdc42/GRAF-dependent endocytosis as well as by macropinocytosis, whereas dynamin-dependent processes are not required. Furthermore, our results indicate that endocytosis of LNCs-PTX is important for the toxic effect on cells. Western blot analysis revealed that LNCs-PTX induce cytotoxicity by means of apoptosis in all the three cell lines. Altogether, the results demonstrate that LNCs-PTX exploit different mechanisms of endocytosis in a cell-type dependent manner, and subsequently induce apoptotic cell death in the breast cancer cells here studied. The article also describes biodistribution studies following intravenous injection of fluorescently labeled LNCs in mice.

Lipid nanocapsules to enhance drug bioavailability to the central nervous system

The central nervous system (CNS), namely the brain, still remains as the hardest area of the human body to achieve adequate concentration levels of most drugs, mainly due to the limiting behavior of its physical and biological defenses. Lipid nanocapsules emerge as a versatile platform to tackle those barriers, and efficiently delivery different drug payloads due to their numerous advantages. They can be produced in a fast, solvent-free and scalable-up process, and their properties can be fine-tuned for to make an optimal brain drug delivery vehicle. Moreover, lipid nanocapsule surface modification can further improve their bioavailability towards the central nervous system. Coupling these features with alternative delivery methods that stem to disrupt or fully circumvent the blood-brain barrier may fully harness the therapeutic advance that lipid nanocapsules can supply to current treatment options. Thus, this review intends to critically address the development of lipid nanocapsules, as well as to highlight the key features that can be modulated to ameliorate their properties towards the central nervous system delivery, mainly through intravenous methods, and how the pathological microenvironment of the CNS can be taken advantage of. The different routes to promote drug delivery towards the brain parenchyma are also discussed, as well as the synergetic effect that can be obtained by combining modified lipid nanocapsules with new/smart administration routes.

T-13 and T-26, the novel taxanes with improved oral bioavailability in rats

In an attempt to improve the oral bioavailability of taxanes, a series of new analogues were synthesized and tested in a panel of human tumor cell lines and cellular permeability assays. Compounds T-13 and T-26 showed potent cytotoxicity and exhibited the highest permeability, so they were selected for pharmacokinetic studies. Here, pharmacokinetics of T-13 and T-26 were studied after intravenous injection (5 mg/kg) and oral administration (60 mg/kg) in male Sprague-Dawley (S.D.) rats, respectively. Plasma concentrations were characterized using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The oral bioavailability of T-13 and T-26 was determined to be 10.71% and 65.79%, respectively. Compounds T-13 and T-26 were both poor substrates of P-glycoprotein (P-gp), and they had a much higher bioavailability than paclitaxel, especially T-26. T-26 with good oral bioavailability represented a potential candidate for potent antitumor activity given oral administration.

Nanostructured lipid carriers with exceptional gastrointestinal stability and inhibition of P-gp efflux for improved oral delivery of tilmicosin

Tilmicosin (TMS) is widely applied to treat porcine bacterial respiratory diseases in veterinary medicine. However, oral administration of TMS is greatly limited due to its physicochemical properties, such as poor water solubility, gastric acid sensitivity and bitterness. Therefore, nanostructured lipid carriers (NLCs) were developed as an oral delivery system for TMS by the high shear method combined with ultrasonic techniques in this study. The results showed that TMS-NLCs were approximately spherical with a hydrodynamic diameter of 283.03 nm and a zeta potential of -30.04 mV. TMS was almost entirely encapsulated in the NLCs by interacting with the lipid matrix, as characterized by differential scanning calorimetry and fourier transform infrared spectroscopy. Thus, TMS-NLCs had an excellent encapsulation efficiency and loading capacity with values of 93.46% and 9.23%, respectively. TMS-NLCs maintained good stability not only during storage at 4 ℃, 25 ℃ and 40 ℃ for 90 days but also in stimulated gastrointestinal (GI) fluids at 37 ℃ for 7 days. Therefore, TMS-NLCs displayed low and sustained release in vitro without an initial burst release in stimulated GI fluids. Furthermore, TMS-NLCs showed higher oral bioavailability in piglets compared to the API suspension. Subsequently, Caco-2 cell monolayers were utilized to analyze the mechanism of NLC-enhanced oral adsorption of TMS. The data revealed that NLCs not only increased cellular uptake of TMS but also inhibited the efflux of P-gp in Caco-2 cells. Additionally, TMS-NLCs mainly entered Caco-2 cells via the caveolae/lipid raft-mediated endocytosis pathway. Moreover, nanoparticles were transported across Caco-2 cell monolayers in the intact form to the basolateral side, as identified by transmission electron microscopy, indicating that TMS-NLCs escape lysosome degradation. Taken together, these results indicate that NLCs are a potential delivery carrier for improving the solubility, permeability and oral bioavailability of TMS.

Model Affitin and PEG modifications onto siRNA lipid nanocapsules: cell uptake and in vivo biodistribution improvements

Malignant melanoma is an aggressive tumor, associated with the presence of local and/or distant metastases. The development of gene therapy by the use of small interfering RNA (siRNA) represents a promising new treatment. However, the protection of this biomolecule is necessary in order for it to be intravenously administrated, for example via its incorporation into nanomedicines. In parallel to the passive targeting usually obtained by pegylation, various studies have aimed at developing “smart” nanomedicines to efficiently deliver the drug to tumor sites. In this work, siRNA loaded lipid nanocapsules (LNCs) were modified with DSPE-polyethylene glycol (DSPE-PEG), tetraether-PEG (TE-PEG) and/or with an Affitin model, to assay multiple targeting strategies. The uptake of fluorescently labelled LNCs, nanocarrier integrity and siRNA release into human SK-Mel28 melanoma cells were studied by flow cytometry, conventional confocal microscopy and by confocal spectral imaging in a Förster Resonance Energy Transfer (FRET) mode. Surface modified siRNA LNCs were followed after human plasma incubation and after intravenous injection, in order to compare the stealth properties. Finally, the biodistribution of the different siRNA LNCs in healthy and melanoma tumor bearing mice models was assessed by in vivo biofluorescence imaging (BFI), to evaluate the potential tumor targeting ability. The post-insertion of DSPE-PEG induced a strong decrease of the internalization into melanoma cells compared to TE-PEG modification. Both PEG polymer decorations induced a great plasma protection of siRNA but only DSPE-PEG led to stealth properties, even at low concentration (5 mM). The Affitin grafting by thiolation of DSPE-PEG was validated on siRNA LNCs. DSPE-PEG-Affitin LNCs were not detected in this melanoma tumor model but did not show unspecific accumulation in organs. DSPE-PEG and TE-PEG LNCs induced a significant intratumoral accumulation of modified LNCs.

Surface modifications of siRNA LNCs were assessed with innovative TE-PEG polymers and an Affitin model, in comparison to classic DSPE-PEG LNCs, in order to evaluate the potential tumor targeting of siRNA after intravenous administration.

Praziquantel-lipid nanocapsules: an oral nanotherapeutic with potential Schistosoma mansoni tegumental targeting

Purpose

Lipid nanocapsules (LNCs) have shown potential to increase the bioavailability and efficacy of orally administered drugs. However, their intestinal translocation to distal target sites and their implication in pharmacokinetic (PK)–pharmacodynamic (PD) relationships are yet to be elucidated. In this study, the effect of LNCs on the PD activity and pharmacokinetics of praziquantel (PZQ), the mainstay of schistosomiasis chemotherapy, was investigated.

Materials and methods

The composition of LNCs was modified to increase PZQ payload and to enhance membrane permeability. PZQ–LNCs were characterized in vitro for colloidal properties, entrapment efficiency (EE%), and drug release. PD activity of the test formulations was assessed in Schistosoma mansoni-infected mice 7 days post-oral administration of a single 250 mg/kg oral dose. Pharmacokinetics of the test formulations and their stability in simulated gastrointestinal (GI) fluids were investigated to substantiate in vivo data.

Results

PZQ–LNCs exhibited good pharmaceutical attributes in terms of size (46–62 nm), polydispersity index (0.01–0.08), EE% (>95%), and sustained release profiles. Results indicated significant efficacy enhancement by reduction in worm burden, amelioration of liver pathology, and extensive damage to the fluke suckers and tegument. This was partly explained by PK data determined in rats. In addition, oral targeting of the worms was supported by the stability of PZQ–LNCs in simulated GI fluids and scanning electron microscopy (SEM) visualization of nanostructures on the tegument of worms recovered from mesenteric/hepatic veins. Cytotoxicity data indicated tolerability of PZQ–LNCs.

Conclusion

Data obtained provide evidence for the ability of oral LNCs to target distal post-absorption sites, leading to enhanced drug efficacy. From a practical standpoint, PZQ–LNCs could be suggested as a potential tolerable single lower dose oral nanomedicine for more effective PZQ mass chemotherapy.

Cytotoxicity and genotoxicity of lipid nanocapsules

Lipid nanocapsules (LNCs) offer a promising method for the entrapment and nanovectorisation of lipophilic molecules. This new type of nanocarrier, formulated according to a solvent-free process and using only regulatory-approved components, exhibits many prerequisites for being well tolerated. Although toxicological reference values have already been obtained in mice, interaction of LNCs at the cell level needs to be elucidated. LNCs, measuring from 27.0±0.1nm (25nm LNCs) and 112.1±1.8nm (100nm LNCs) and with a zeta potential between -38.7±1.2mV and +9.18±0.4mV, were obtained by a phase inversion process followed by post-insertion of carboxy- or amino-DSPE-PEG. Trypan blue, MTS and neutral red uptake (NRU) assays were performed to evaluate the cytotoxicity of LNCs on mouse macrophage-like cells RAW264.7 after 24h of exposure. The determination of 50% lethal concentration (LC50) showed a size effect of LNCs on toxicity profiles: LC50 ranged from 1.036mg/L (MTS) and 0.477mg/mL (NRU) for 25nm LNCs, to 4.42mg/mL (MTS) and 2.18mg/mL (NRU) for 100nm LNCs. Surfactant Solutol® HS15 has been shown to be the only constituent to exhibit cytotoxicity; its LC50 reached 0.427mg/mL. Moreover, LNCs were not more toxic than their components in simple mixtures. At sublethal concentration, 100nm LNCs only were able to induce a significant production of nitric oxide (NO) by RAW264.7 cells, as assessed by the Griess reaction. Again, surfactant was the only component responsible for an increased NO release (1.8±0.2-fold). Genotoxicity assays revealed no DNA damage on human lymphocytes in both the in vitro Comet and micronucleus assays using 4-hour and 24-hour treatments, respectively.

Lipid nanocapsules maintain full integrity after crossing a human intestinal epithelium model

Lipid nanocapsules (LNCs) have demonstrated great potential for the oral delivery of drugs having very limited oral bioavailability (BCS class II, III and IV molecules). It has been shown previously that orally-administered LNCs can permeate through mucus, increase drug absorption by the epithelial tissue, and finally, increase drug bioavailability. However, even if transport mechanisms through mucus and the intestinal barrier have already been clarified, the preservation of particle integrity is still not known. The aim of the present work is to study in vitro the fate of LNCs after their transportation across an intestinal epithelium model (Caco-2 cell model). For this, two complementary techniques were employed: Förster Resonance Energy Transfer (FRET) and Nanoparticle Tracking Analysis (NTA). Results showed, after 2h, the presence of nanoparticles in the basolateral side of the cell layer and a measurable FRET signal. This provides very good evidence for the transcellular intact crossing of the nanocarriers.

Mechanisms of transport of polymeric and lipidic nanoparticles across the intestinal barrier

Unraveling the mechanisms of nanoparticle transport across the intestinal barrier is essential for designing more efficient nanoparticles for oral administration. The physicochemical parameters of the nanoparticles (e.g., size, surface charge, chemical composition) dictate nanoparticle fate across the intestinal barrier. This review aims to address the most important findings regarding polymeric and lipidic nanoparticle transport across the intestinal barrier, including the evaluation of critical physicochemical parameters of nanoparticles that affect nanocarrier interactions with the intestinal barrier.

How to design the surface of peptide-loaded nanoparticles for efficient oral bioavailability?

The oral administration of proteins is a current challenge to be faced in the field of therapeutics. There is currently much interest in nanocarriers since they can enhance oral bioavailability. For lack of a clear definition, the key characteristics of nanoparticles have been highlighted. Specific surface area is one of these characteristics and represents a huge source of energy that can be used to control the biological fate of the carrier. The review discusses nanocarrier stability, mucus interaction and absorption through the intestinal epithelium. The protein corona, which has raised interest over the last decade, is also discussed. The universal ideal surface is a myth and over-coated carriers are not a solution either. Besides, common excipients can be useful on several targets. The suitable design should rather take into account the composition, structure and behavior of unmodified nanomaterials.

Characterization and comparison of two novel nanosystems associated with siRNA for cellular therapy

To direct stem cell fate, a delicate control of gene expression through small interference RNA (siRNA) is emerging as a new and safe promising strategy. In this way, the expression of proteins hindering neuronal commitment may be transiently inhibited thus driving differentiation. Mesenchymal stem cells (MSC), which secrete tissue repair factors, possess immunomodulatory properties and may differentiate towards the neuronal lineage, are a promising cell source for cell therapy studies in the central nervous system. To better drive their neuronal commitment the repressor Element-1 silencing transcription (REST) factor, may be inhibited by siRNA technology. The design of novel nanoparticles (NP) capable of safely delivering nucleic acids is crucial in order to successfully develop this strategy. In this study we developed and characterized two different siRNA NP. On one hand, sorbitan monooleate (Span(®)80) based NP incorporating the cationic components poly-l-arginine or cationized pullulan, thus allowing the association of siRNA were designed. These NP presented a small size (205 nm) and a negative surface charge (-38 mV). On the other hand, lipid nanocapsules (LNC) associating polymers with lipids and allowing encapsulation of siRNA complexed with lipoplexes were also developed. Their size was of 82 nm with a positive surface charge of +7 mV. Both NP could be frozen with appropriate cryoprotectors. Cytotoxicity and transfection efficiency at different siRNA doses were monitored by evaluating REST expression. An inhibition of around 60% of REST expression was observed with both NP when associating 250 ng/mL of siRNA-REST, as recommended for commercial reagents. Span NP were less toxic for human MSCs than LNCs, but although both NP showed a similar inhibition of REST over time and the induction of neuronal commitment, LNC-siREST induced a higher expression of neuronal markers. Therefore, two different tailored siRNA NP offering great potential for human stem cell differentiation have been developed, encouraging the pursuit of further in vitro and in vivo in studies.

Bypassing P-Glycoprotein Drug Efflux Mechanisms: Possible Applications in Pharmacoresistant Schizophrenia Therapy

The efficient noninvasive treatment of neurodegenerative disorders is often constrained by reduced permeation of therapeutic agents into the central nervous system (CNS). A vast majority of bioactive agents do not readily permeate into the brain tissue due to the existence of the blood-brain barrier (BBB) and the associated P-glycoprotein efflux transporter. The overexpression of the MDR1 P-glycoprotein has been related to the occurrence of multidrug resistance in CNS diseases. Various research outputs have focused on overcoming the P-glycoprotein drug efflux transporter, which mainly involve its inhibition or bypassing mechanisms. Studies into neurodegenerative disorders have shown that the P-glycoprotein efflux transporter plays a vital role in the progression of schizophrenia, with a noted increase in P-glycoprotein function among schizophrenic patients, thereby reducing therapeutic outcomes. In this review, we address the hypothesis that methods employed in overcoming P-glycoprotein in cancer and other disease states at the level of the BBB and intestine may be applied to schizophrenia drug delivery system design to improve clinical efficiency of drug therapies. In addition, the current review explores polymers and drug delivery systems capable of P-gp inhibition and modulation.

EM-E-11-4 increases paclitaxel uptake by inhibiting P-glycoprotein-mediated transport in Caco-2 cells

P-glycoprotein (P-gp) overexpression is the main mechanism involved in chemotherapy drug resistance such as paclitaxel resistance and therapy failure. The most widely studied P-gp inhibitors still have limited ability to reverse resistance in the clinic. In this study, EM-E-11-4, a lathyrane-type diterpenoid isolated from Euphorbia micractina, was found to significantly increase paclitaxel uptake in Caco-2 cells, which functionally overexpressed P-gp. In vitro transport experiments, carried out in the Caco-2 monolayer model, indicated that EM-E-11-4 significantly reduced the efflux ratio of paclitaxel transport by inhibiting P-gp function without affecting P-gp expression. We also found that EM-E-11-4 enhanced the intracellular accumulation of paclitaxel in a dose-dependent manner by LC-MS/MS and EM-E-11-4 showed low cytotoxicity. Hence, EM-E-11-4 is an effective potential agent to reverse P-gp-mediated paclitaxel resistance by inhibiting P-gp transport function and increasing the intracellular concentration of paclitaxel.

In vivo evaluation of paclitaxel-loaded lipid nanocapsules after intravenous and oral administration on resistant tumor

Aim & methods: The aim of the present work was to encapsulate paclitaxel (Ptx) in various lipid nanocapsules (LNCs) formulations and then to compare their pharmacokinetics and efficacy on a subcutaneous isograft model in rats. Results: Three different Ptx formulations were obtained. Drug payloads ranged from 1.32 to 3.62 mg Ptx/g of formulation. After oral administration the area under concentration–time curve was higher (p < 0.05) if Ptx was encapsulated, (1,2 Distearoyl-sn-glycero-3–phosphoethanolamine-N-[amino(PEG)] (DSPE-PEG-NH2)) LNCs displaying the highest area under concentration–time curve (p < 0.05). Efficacy was better than control for standard LNCs after oral administration (p < 0.05) and for (DSPE-PEG-NH2) LNCs after intravenous administration. Despite good absorption, (DSPE-PEG-NH2) LNCs failed to remain efficient after oral route. Conclusion: This study highlights the importance of efficacy studies paired to pharmacokinetic studies for nanomedicines.

Fate of paclitaxel lipid nanocapsules in intestinal mucus in view of their oral delivery

The bioavailability of paclitaxel (Ptx) has previously been improved via its encapsulation in lipid nanocapsules (LNCs). In this work, the interactions between LNCs and intestinal mucus are studied because they are viewed as an important barrier to successful oral delivery. The rheological properties of different batches of pig intestinal mucus were studied under different conditions (the effect of hydration and the presence of LNCs). Fluorescence resonance energy transfer (FRET) was used to study the stability of LNCs in mucus at 37°C for at least 3 hours. Diffusion through 223, 446, and 893 μm mucus layers of 8.4, 16.8, and 42 μg/mL Ptx formulated as Taxol® (Bristol-Myers Squibb, Rueil-Malmaison, France) or encapsulated in LNCs (Ptx-LNCs) were investigated. The effect of the size of the LNCs on their diffusion was also investigated (range, 25–110 nm in diameter). Mucus behaves as a non-Newtonian gel with rheofluidifying properties and a flow threshold. The viscous (G″) and elastic (G′) moduli and flow threshold of the two mucus batches varied with water content, but G′ remained below G″. LNCs had no effect on mucus viscosity and flow threshold. The FRET efficiency remained at 78% after 3 hours. Because the destruction of the LNCs would lead to a FRET efficiency below 25%, these results suggest only a slight modification of LNCs after their contact with mucus. The diffusion of Taxol® and Ptx-LNCs in mucus decreases if the mucus layer is thicker. Interestingly, the apparent permeability across mucus is higher for Ptx-LNCs than for Taxol® for drug concentrations of 16.8 and 42 μg/mL Ptx (P<0.05). The diffusion of Ptx-LNCs through mucus is not size-dependent. This study shows that LNCs are stable in mucus, do not change mucus rheological properties, and improve Ptx diffusion at low concentrations, thus making these systems good candidates for Ptx oral delivery. The study of the physicochemical interaction between the LNC surface and its diffusion in mucus is now envisioned.

Nanosolvated microtubule-modulating chemotherapeutics: a case-to-case study

About 10% of the drugs in the preclinical stage are poorly soluble, 40% of the drugs in the pipeline have poor solubility, and even 60% of drugs coming directly from synthesis have aqueous solubility below 0.1 mg/ml. Out of the research around, 40% of lipophilic drug candidates fail to reach the market despite having potential pharmacodynamic activities. Microtubule-modulating chemotherapeutics is an important class of cancer chemotherapy. Most chemotherapeutics that belong to this category are plant-derived active constituents, such as vincristine, vinblastine, colchicine, docetaxel, paclitaxel, and noscapinoids. The pKa of a drug considerably affects its solubility in physiological fluids and consequently bioavailability. It usually ranges from 5 to 12 for microtubule-modulating drugs. Hence, the solubility of these drugs in physiological fluids is considerably affected by a change in pH. However, because of unpredictable parameters involved in poor solubility and the low oral bioavailability of these chemotherapeutics during the early phases of drug development, they often have an unusual pharmacokinetic profile. This makes the development process of novel chemotherapeutics slow, inefficient, patient-unfriendly, and very costly, emphasizing a need for more rational approaches on the basis of preclinical concepts. Nanosolvation is a process of increasing the polarity of a hydrophobic molecule either by solvation or cavitization in a hydrophilic macrocycle. The present review therefore focuses on the techniques applied in nanosolvation of microtubule-modulating chemotherapeutics to enhance solubility and bioavailability. The methodologies described will be highly beneficial for anticancer researchers to follow a trend of rational drug development.

Association between reversal of multidrug resistance by methyl jasmonate and P-glycoprotein ATPase activity in hepatocellular carcinoma

OBJECTIVE

To study the effects of methyl jasmonate on multidrug resistance in a mouse model of hepatocellular carcinoma.

METHODS

Multidrug resistant H22 (H22/FAP) hepatocellular carcinoma cells were produced in vitro by continuous exposure to increasing doses of doxorubicin, cisplatin and 5-fluorouracil (FAP regimen). Cell toxicity was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolum bromide (MTT) assay. Survival time was calculated for BALB/c mice that received intraperitoneal injections of H22/FAP cells followed by treatment with methyl jasmonate or verapamil in combination with FAP for 7 days. Adenosine triphosphate (ATP) hydrolysis was used to measure the activity of permeability-glycoprotein (P-gp) ATPase activity in plasma membranes.

RESULTS

The MTT assay showed that methyl jasmonate significantly enhanced the cytotoxicity of the FAP regimen in multidrug resistant H22/FAP cells. Methyl jasmonate (10 mg/kg and 5 mg/kg) combined with FAP significantly increased survival time in BALB/c mice by 44.25% and 48.01%, respectively, compared with FAP. Methyl jasmonate increased P-gp ATPase activity.

CONCLUSION

The combined use of methyl jasmonate and the FAP regimen might be a novel strategy for overcoming the multidrug resistance often observed in hepatocellular carcinoma.

Development and in vitro evaluation of a novel lipid nanocapsule formulation of etoposide

Small cell lung cancer (SCLC) is the most aggressive carcinoma in thoracic oncology, unfortunately, despite chemotherapy, relapse is constant. The effect of etoposide, a major drug used against SCLC, can potentially be enhanced after its encapsulation in nanocarriers. The aim of this study was to use the technology of lipid nanocapsules (LNCs) to obtain nanocarriers with drug loadings compatible with clinical use and with an industrial process. Solubility studies with different co-solvent were first performed, then several process were developed to obtain LNCs. LNCs were then characterized (size, zeta potential, and drug loading). The best formulation called Ω-LNCs had a size of 54.1±2.0 nm and a zeta potential of -5.8±3.5 mV and a etoposide drug loading of 5.7±0.3mg/g. The characteristics of this formulation were maintained after freeze drying and after a 15× scale-up. Release studies in a media mimicking plasma composition showed that 40% of the drug was released from the LNCs after 48 h. Moreover the activity of etoposide after encapsulation was enhanced on H209 cells, IC50 was 100 μM and 2.5 μM for etoposide and etoposide LNCs respectively. Unfortunately the formulation failed to be more cytotoxic than etoposide alone on H69AR cells that are resistant to etoposide. This study showed that is was possible to obtain a new etoposide nanocarrier without the use of organic solvent, that the process is suitable for scale-up and freeze drying and finally that etoposide activity is maintained which is very promising for future treatment of SCLC.

Polymeric micelles, a promising drug delivery system to enhance bioavailability of poorly water-soluble drugs

Oral administration is the most commonly used and readily accepted form of drug delivery; however, it is find that many drugs are difficult to attain enough bioavailability when administered via this route. Polymeric micelles (PMs) can overcome some limitations of the oral delivery acting as carriers able to enhance drug absorption, by providing (1) protection of the loaded drug from the harsh environment of the GI tract, (2) release of the drug in a controlled manner at target sites, (3) prolongation of the residence time in the gut by mucoadhesion, and (4) inhibition of efflux pumps to improve the drug accumulation. To explain the mechanisms for enhancement of oral bioavailability, we discussed the special stability of PMs, the controlled release properties of pH-sensitive PMs, the prolongation of residence time with mucoadhesive PMs, and the P-gp inhibitors commonly used in PMs, respectively. The primary purpose of this paper is to illustrate the potential of PMs for delivery of poorly water-soluble drugs with bioavailability being well maintained.

Pharmaceutical nanotechnology for oral delivery of anticancer drugs

Oral chemotherapy is an important topic in the 21st century medicine, which may radically change the current regimen of chemotherapy and greatly improve the quality of life of the patients. Unfortunately, most anticancer drugs, especially those of high therapeutic efficacy such as paclitaxel and docetaxel, are not orally bioavailable due to the gastrointestinal (GI) drug barrier. The molecular basis of the GI barrier has been found mainly due to the multidrug efflux proteins, i.e. P-type glycoproteins (P-gp), which are rich in the epithelial cell membranes in the GI tract. Medical solution for oral chemotherapy is to apply P-gp inhibitors such as cyclosporine A, which, however, suppress the body's immune system either, thus causing medical complication. Pharmaceutical nanotechnology, which is to apply and further develop nanotechnology to solve the problems in drug delivery, may provide a better solution and thus change the way we make drug and the way we take drug. This review is focused on the problems encountered in oral chemotherapy and the pharmaceutical nanotechnology solutions such as prodrugs, nanoemulsions, dendrimers, micelles, liposomes, solid lipid nanoparticles and nanoparticles of biodegradable polymers. Proof-of-concept in vitro and in vivo results for oral delivery of anticancer drugs by the various nanocarriers, which can be found so far from the literature, are provided.

Lipid nanocapsule functionalization by lipopeptides derived from human papillomavirus type-16 capsid for nucleic acid delivery into cancer cells

Plasmid DNA (pDNA) and small interfering RNAs (siRNAs) are very useful tools for the treatment of cancer. However, pDNA and siRNAs efficacy is restricted by their negative charge and susceptibility to degradation by endonucleases that prevent them penetrating tissue and cellular barriers such as the plasma and endolysosomal membranes. Viral vectors have some advantages but their use is largely limited by their immunogenicity. On the other hand, synthetic nanoparticles have advantage of being relatively non-immunogenic but their ability to deliver nucleic acids remains less efficient than their viral counterparts. The present study is focussed on the development and evaluation of biomimetic lipid nanocapsules (LNCs) functionalized with a L1 papillomavirus type-16 capsid-derived lipopeptide on their surface, for transfection of U87MG glioma cells and Caco-2 colorectal adenocarcinoma cells with pDNA or siRNAs. Since the L1-peptide has been described as a nuclear localization signal able to complex with nucleic acids and bind to heparan sulfate on the cell surface, the structure and function of L1-peptide bound to LNCs (L1-LNCs) were investigated. Although L1-LNCs were shown to complex with both pDNA and siRNAs, the pDNA-L1-LNC complexes showed only weak transfection efficiency. In contrast, siRNA-L1-LNC complexes appeared as effective repressors of targeted messengers.

Silencing of miR-21 by locked nucleic acid-lipid nanocapsule complexes sensitize human glioblastoma cells to radiation-induced cell death

The recent discovery of microRNA (miRNA) as major post-transcriptional repressors prompt the interest of developing novel approaches to target miRNA pathways to improve therapy. In this context, although the most significant barrier to their widespread clinical use remains delivery, nuclease-resistant locked nucleic acid (LNA) that bind specifically and irreversibly to miRNA represent interesting weapons. Thus, by focusing on oncongenic miR-21 miRNA, which participate to cancer cell resistance to apoptotic signals, the aim of the present study was to investigate the possibility of silencing miRNA by LNA conjugated to lipid nanocapsules (LNCs) as miRNA-targeted nanomedicines in U87MG glioblastoma (GBM) cells. After synthesis of an amphiphilic lipopeptide affine for nucleic acids, a post-insertion procedure during the LNC phase inversion formulation process allowed to construct peptide-conjugated LNCs. Peptide-conjugated LNCs were then incubated with LNAs to allow the formation of complexes characterized in gel retardation assays and by their physicochemical properties. U87MG cell treatment by LNA-LNC complexes resulted in a marked reduction of miR-21 expression as assessed by RTqPCR. In addition, exposure of U87MG cells to LNA-LNC complexes followed by external beam radiation demonstrated a significant improvement of cell sensitivity to treatment and emphasizes the interest to investigate further this miRNA-targeted strategy.

Paclitaxel Nano-Delivery Systems: A Comprehensive Review

Paclitaxel is one of the most effective chemotherapeutic drugs ever developed and is active against a broad range of cancers, such as lung, ovarian, and breast cancers. Due to its low water solubility, paclitaxel is formulated in a mixture of Cremophor EL and dehydrated ethanol (50:50, v/v) a combination known as Taxol. However, Taxol has some severe side effects related to Cremophor EL and ethanol. Therefore, there is an urgent need for the development of alternative Taxol formulations. The encapsulation of paclitaxel in biodegradable and non-toxic nano-delivery systems can protect the drug from degradation during circulation and in-turn protect the body from toxic side effects of the drug thereby lowering its toxicity, increasing its circulation half-life, exhibiting improved pharmacokinetic profiles, and demonstrating better patient compliance. Also, nanoparticle-based delivery systems can take advantage of the enhanced permeability and retention (EPR) effect for passive tumor targeting, therefore, they are promising carriers to improve the therapeutic index and decrease the side effects of paclitaxel. To date, paclitaxel albumin-bound nanoparticles (Abraxane®) have been approved by the FDA for the treatment of metastatic breast cancer and non-small cell lung cancer (NSCLC). In addition, there are a number of novel paclitaxel nanoparticle formulations in clinical trials. In this comprehensive review, several types of developed paclitaxel nano-delivery systems will be covered and discussed, such as polymeric nanoparticles, lipid-based formulations, polymer conjugates, inorganic nanoparticles, carbon nanotubes, nanocrystals, and cyclodextrin nanoparticles.

Anti-inflammatory properties of anthraquinones and their relationship with the regulation of P-glycoprotein function and expression

There is a growing interest in natural products that potentially have anti-inflammatory properties and inhibit P-glycoprotein (P-gp) function. In this report, we assessed the effects of anthraquinone derivatives from rhubarb on LPS-induced RAW 264.7 macrophages to determine their anti-inflammatory potential. The derivatives were also tested in Caco-2 cell lines to evaluate the inhibition of the drug efflux function of P-gp. The transport abilities were examined and the cellular accumulation of rhodamine-123 (R-123) was also measured. Electorphoretic mobility shift assay (EMSA) was performed to check the activator protein-1 (AP-1) DNA binding affinity. Five anthraquinones were tested to determine their inhibitory activities on NO production and the protein and mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Furthermore, the level of prostaglandin E(2) (PGE(2)) was determined in LPS-induced RAW264.7 macrophages. Emodin was found to be the most potent inhibitor, and it also reduced paw swelling in the mouse model of carrageenan-induced paw edema. In Caco-2 cells, emodin elevated the accumulation of R-123 and decreased the efflux ratio of R-123, which indicates the inhibition of P-gp function. The inhibition of COX-2 protein by emodin paralleled the decrease in P-gp expression. In addition, mitogen-activated protein kinase (MAPK) expression was decreased through the prevention of AP-1 DNA binding, which leads to downregulation in the expression of P-gp. Our data indicate that the decrease of P-gp expression is caused by the decreased expression of COX-2 through the MAPK/AP-1 pathway. Based on our results, we suggest that anti-inflammatory drugs with COX-2 inhibitory activity might be used to modulate P-gp function and expression.

Lipid-based liquid crystalline nanoparticles as oral drug delivery vehicles for poorly water-soluble drugs: cellular interaction and in vivo absorption

Background

Lipid-based liquid crystalline nanoparticles (LCNPs) have attracted growing interest as novel drug-delivery systems for improving the bioavailability of both hydrophilic and hydrophobic drugs. However, their cellular interaction and in vivo behavior have not been fully developed and characterized.

Methods

In this study, self-assembled LCNPs prepared from soy phosphatidylcholine and glycerol dioleate were developed as a platform for oral delivery of paclitaxel. The particle size of empty LCNPs and paclitaxel-loaded LCNPs was around 80 nm. The phase behavior of the liquid crystalline matrix was characterized using crossed polarized light microscopy and small-angle X-ray scattering, and showed both reversed cubic and hexagonal phase in the liquid crystalline matrix. Transmission electron microscopy and cryofield emission scanning electron microscopy analysis revealed an inner winding water channel in LCNPs and a “ ball-like”/“hexagonal” morphology.

Results

Cellular uptake of LCNPs in Caco-2 cells was found to be concentration-dependent and time-dependent, with involvement of both clathrin and caveolae/lipid raft-mediated endocytosis. Under confocal laser scanning microscopy, soy phosphatidylcholine was observed to segregate from the internalized LCNPs and to fuse with the cell membrane. An in vivo pharmacokinetic study showed that the oral bioavailability of paclitaxel-loaded LCNPs (13.16%) was 2.1 times that of Taxol^® (the commercial formulation of paclitaxel, 6.39%).

Conclusion

The findings of this study suggest that this LCNP delivery system may be a promising candidate for improving the oral bioavailability of poorly water-soluble agents.

Tumor eradication in rat glioma and bypass of immunosuppressive barriers using internal radiation with (188)Re-lipid nanocapsules

To date, glioblastoma treatments have only been palliative. In this context, locoregional drug delivery strategies, which allow for blood--brain barrier bypass and reduced systemic toxicity, are of major significance. Recent progress in nanotechnology has led to the development of colloidal carriers of radiopharmaceutics, such as lipid nanocapsules loaded with rhenium-188 (LNC(188)Re-SSS) that are implanted in the brain. In our study, we demonstrated that fractionated internal radiation using LNC(188)Re-SSS triggered remarkable survival responses in a rat orthotopic glioma model (cure rates of 83%). We also highlighted the importance of the radioactivity activity gradient obtained by combining a simple stereotactic injection (SI) with convection-enhanced delivery (CED).We assumed that the immune system played a role in the treatment's efficacy on account of the overproduction of peripheral cytokines, recruitment of immune cells to the tumor site, and memory response in long-term survivor animals. Hence, nanovectorized internal radiation therapy with activity gradients stimulating immune responses may represent a new and interesting alternative for the treatment of solid tumors such as glioblastomas.

Development and characterization of immuno-nanocarriers targeting the cancer stem cell marker AC133

In the context of targeted therapy, we addressed the possibility of developing a drug delivery nanocarrier capable to specifically reach cancer cells that express the most prominent marker associated with cancer stem cell (CSC) phenotype, AC133. For this purpose, 100nm lipid nanocapsules (LNCs) were functionalized with a monoclonal antibody (mAb) directed against AC133 according to two distinct methods: firstly, post-insertion within 100nm LNCs of a lipid poly(ethylene glycol) functionalized with reactive-sulfhydryl maleimide groups (DSPE-PEG(2000)-maleimide) followed by thiolated mAb coupling, and, secondly, creation of a thiolated lipo-immunoglobulin between DSPE-PEG(2000)-maleimide and AC133, then post-inserted within LNCs. Due to the reduced number of purification steps, lower amounts of DSPE-PEG(2000)-maleimide that were necessary as well as lower number of free maleimide functions present onto the surface of immuno-LNC, the second method was found to be more appropriate. Thus, 126nm AC133-LNC with a zeta potential of -22mV while keeping a narrow distribution were developed. Use of the IgG1κ isotype control-immunoglobulins produced similar control IgG1-LNCs. Micro-Bradford colorimetric assay indicated a fixation of about 40 immunoglobulins per LNC. Use of human Caco-2 cells that constitutively express AC133 (Caco-2-AC133(high)) allowed addressing the behavior of the newly functionalized immuno-LNCs. siRNA knockown strategy permitted to obtain Caco-2-AC133(low) for comparison. Immunofluorescence-combined flow cytometry analysis demonstrated that the epitope-recognition function of AC133 antibody was preserved when present on immuno-LNCs. Although grafting of immunoglobulins onto the surface of LNCs repressed their internalization within Caco-2 cells as evaluated by flow cytometry, AC133-specific cellular binding was obtained with AC133-LNC as assessed by computer-assisted fluorescence microscopy. In conclusion, interest of AC133-LNCs as niche carriers is discussed toward the development of CSC targeted chemo- or radio-nanomedicines.

The importance of endo-lysosomal escape with lipid nanocapsules for drug subcellular bioavailability

To establish the therapeutic relevance of new nanocarriers, rationalization of knowledge on their interactions with biological structures is essential. In the present study, we have investigated endocytosis and intracellular trafficking of lipid nanocapsules (LNCs) in rat glioma cells. Radiolabelled and fluorescent LNCs were synthesized by using a phase inversion process that follows the formation of an oil/water microemulsion containing triglycerides, lecithins and a non-ionic surfactant, the hydroxystearate of poly(ethylene glycol) (HS-PEG). Our data revealed that LNCs were rapidly accumulated within cells (from 2 min exposure) through active and saturating mechanisms involving endogenous cholesterol with a major contribution of clathrin/caveolae-independent pathways. Although initially present in endosomes, LNCs can bypass the endo-lysosomal compartment with only 10% of the cell-internalized fraction found in isolated lysosomes after 2 h exposure. As demonstrated by use of lysosomal probes, LNCs reverted lysosome integrity similarly to V-ATPase inhibitors and in a size-dependent fashion with best efficiency for small nanoparticles. When loaded with paclitaxel, smallest LNCs also triggered the best cell death activity. Those LNC properties are ascribed to the proportion of HS-PEG they provided to the cell. They are important to consider toward the development of nanomedicines that use drugs sensitive to lysosomal degradation or that need to reach extra endo-lysosomal targets.