Multifunctional Poly(methyl vinyl ether-co-maleic anhydride)-graft-hydroxypropyl-β-cyclodextrin Amphiphilic Copolymer as an Oral High-Performance Delivery Carrier of Tacrolimus

Self-micellizing solid dispersion of tacrolimus: Physicochemical and pharmacokinetic characterization

The present study was undertaken to develop a self-micellizing solid dispersion (SMSD) of tacrolimus (TAC) to improve the biopharmaceutical properties of TAC. An SMSD formulation of TAC (SMSD/TAC) and amorphous solid dispersion formulation of TAC (ASD/TAC) were prepared with Soluplus® , an amphiphilic copolymer, and hydroxypropyl cellulose, respectively. Physicochemical properties were characterized in terms of morphology, crystallinity, storage stability, interaction of TAC with Soluplus® , and micelle-forming potency; pharmacokinetic behavior was also evaluated in rats. Tacrolimus in both formulations was in an amorphous state. After storage at 40°C/75% relativity humidity for 4 weeks, there were no significant changes in the crystallinity of TAC between nonaged and aged SMSD/TAC, whereas slight recrystallization was observed in aged ASD/TAC. The results of circular dichroism (CD) and infrared spectroscopic analyses were indicative of the potent drug-polymer interaction in SMSD/TAC, possibly leading to the prevention of recrystallization. Compared with other TAC samples, SMSD/TAC exhibited significant improvement in the dissolution behavior of TAC through the immediate formation of fine micelles. After the oral administration of TAC samples (10 mg TAC/kg) to rats, there was marked enhancement in systemic exposure to TAC with both formulations; in particular, SMSD/TAC achieved an increase in bioavailability ca. 20-fold higher than crystalline TAC. The SMSD approach might provide an effective dosage form for TAC with enhanced physicochemical stability and oral absorption.

Mechanisms of Nanoparticle Transport across Intestinal Tissue: An Oral Delivery Perspective

Oral drug administration has been a popular choice due to patient compliance and limited clinical resources. Orally delivered drugs must circumvent the harsh gastrointestinal (GI) environment to effectively enter the systemic circulation. The GI tract has a number of structural and physiological barriers that limit drug bioavailability including mucus, the tightly regulated epithelial layer, immune cells, and associated vasculature. Nanoparticles have been used to enhance oral bioavailability of drugs, as they can act as a shield to the harsh GI environment and prevent early degradation while also increasing uptake and transport of drugs across the intestinal epithelium. Evidence suggests that different nanoparticle formulations may be transported via different intracellular mechanisms to cross the intestinal epithelium. Despite the existence of a significant body of work on intestinal transport of nanoparticles, many key questions remain: What causes the poor bioavailability of the oral drugs? What factors contribute to the ability of a nanoparticle to cross different intestinal barriers? Do nanoparticle properties such as size and charge influence the type of endocytic pathways taken? In this Review, we summarize the different components of intestinal barriers and the types of nanoparticles developed for oral delivery. In particular, we focus on the various intracellular pathways used in nanoparticle internalization and nanoparticle or cargo translocation across the epithelium. Understanding the gut barrier, nanoparticle characteristics, and transport pathways may lead to the development of more therapeutically useful nanoparticles as drug carriers.

Rapid quantification of 2,4-dichlorophenol in river water samples using molecularly imprinted polymers coupled to ambient plasma mass spectrometry

Rapid quantification of environmental pollutants is important for water quality control and environmental monitoring. In this work, we report the development of molecularly imprinted polymers (MIPs) obtained from poly(methyl vinyl ether-alt-maleic acid) polymer. The synthesized materials were used for selective preconcentration of 2,4-dichlorophenol, a priority pollutant which creates a threat to public health. The structure of poly(methyl vinyl ether-alt-maleic acid) was functionalized with 4-aminomethylpyridine (4-AMP) to incorporate pyridine groups presumably responsible for increased affinity towards 2,4-dichlorophenol. The synthesis was performed with different degree (10%, 20% and 30%) of 4-AMP functionalization to investigate the influence of pyridine group content on the final MIPs properties. The molecular imprinting process was conducted by amidation of polymers' anhydride groups with diethylenetriamine. Moreover, the experimental data indicated that maximum adsorption capacity was observed for the highest 4-AMP functionalization degree. Similarly, MIPs with the highest 4-AMP content proved to possess the highest selectivity towards the analyte. Finally, the functionalized MIPs were used to quantify 2,4-dichlorophenol by their direct introduction into a specially designed ambient mass spectrometry setup. The detection limits were improved significantly over the ones measured for pure analyte solution. The proposed analytical technique was used to quantify 2,4-dichlorophenol in river water and wastewater samples. Good recovery results were obtained, which proves that the method can be used for analysis of complex real-life samples.

Promising strategies for improving oral bioavailability of poor water-soluble drugs

INTRODUCTION

Oral administration of poorly water-soluble drugs (PWSDs) is generally related to low bioavailability, leading to high drug doses, multiple side effects, and low patient compliance. Thus, different strategies have been developed to increase drug solubility and dissolution in the gastrointestinal tract, opening new venues for these drugs.

AREAS COVERED

This review outlines the current challenges in PWSD formulation development and the strategies to overcome the oral barriers and increase their solubility and bioavailability. Conventional strategies include altering crystalline and molecular structures and modifying oral solid dosage forms. In contrast, novel strategies comprise micro- and nanostructured systems. Recent representative studies involving how these strategies have improved the oral bioavailability of PWSDs were also reviewed and reported.

EXPERT OPINION

New approaches to enhance PWSD bioavailability have sought to improve water solubility and dissolution rates, drug protection by overcoming biological barriers, and increased absorption. Still, only a handful of studies have focused on quantifying the increase in bioavailability. Improving the oral bioavailability of PWSDs remains an exciting unexplored field of research and has become an important issue for successfully developing pharmaceutical products.

Polymeric nanomedicines for the treatment of hepatic diseases

The liver is an important organ in the human body and performs many functions, such as digestion, detoxification, metabolism, immune responses, and vitamin and mineral storage. Therefore, disorders of liver functions triggered by various hepatic diseases, including hepatitis B virus infection, nonalcoholic steatohepatitis, hepatic fibrosis, hepatocellular carcinoma, and transplant rejection, significantly threaten human health worldwide. Polymer-based nanomedicines, which can be easily engineered with ideal physicochemical characteristics and functions, have considerable merits, including contributions to improved therapeutic outcomes and reduced adverse effects of drugs, in the treatment of hepatic diseases compared to traditional therapeutic agents. This review describes liver anatomy and function, and liver targeting strategies, hepatic disease treatment applications and intrahepatic fates of polymeric nanomedicines. The challenges and outlooks of hepatic disease treatment with polymeric nanomedicines are also discussed.

Poly (maleic anhydride-alt-1-octadecene)-based bioadhesive nanovehicles improve oral bioavailability of poor water-soluble gefitinib

The poor water solubility and inadequate oral bioavailability of gefitinib (Gef) remains a critical issue to achieve the therapeutic outcomes. Herein, we designed a poly (maleic anhydride-alt-1-octadecene) (PMA/C18) based lipid nanovehicle (PLN) to improve the intestinal absorption and oral bioavailability of poorly water-soluble Gef. PLN was nanometer-sized particles, and Gef was dispersed in the PLN formulation as amorphous or molecular state. At 4 h of oral administration, the tissue concentration of Gef in duodenum, jejunum and ileum was profoundly enhanced 3.37-, 8.94- and 8.09-fold by PLN when comparing to the counterpart lipid nanovehicle. Moreover, the oral bioavailability of Gef was significantly enhanced 2.48-fold by the PLN formulation when comparing to the free drug suspension. Therefore, this study provides an encouraging bioadhesive delivery platform to improve the oral delivery of poorly water-soluble drugs.

Strategies and Mechanism in Reversing Intestinal Drug Efflux in Oral Drug Delivery

Efflux transporters distributed at the apical side of human intestinal epithelial cells actively transport drugs from the enterocytes to the intestinal lumen, which could lead to extremely poor absorption of drugs by oral administration. Typical intestinal efflux transporters involved in oral drug absorption process mainly include P-glycoprotein (P-gp), multidrug resistance proteins (MRPs) and breast cancer resistance protein (BCRP). Drug efflux is one of the most important factors resulting in poor absorption of oral drugs. Caco-2 monolayer and everted gut sac are sued to accurately measure drug efflux in vitro. To reverse intestinal drug efflux and improve absorption of oral drugs, a great deal of functional amphiphilic excipients and inhibitors with the function of suppressing efflux transporters activity are generalized in this review. In addition, different strategies of reducing intestinal drugs efflux such as silencing transporters and the application of excipients and inhibitors are introduced. Ultimately, various nano-formulations of improving oral drug absorption by inhibiting intestinal drug efflux are discussed. In conclusion, this review has significant reference for overcoming intestinal drug efflux and improving oral drug absorption.

Tacrolimus-Loaded Solid Lipid Nanoparticle Gel: Formulation Development and In Vitro Assessment for Topical Applications

The currently available topical formulations of tacrolimus have minimal and variable absorption, elevated mean disposition half-life, and skin irritation effects resulting in patient noncompliance. In our study, we fabricated tacrolimus-loaded solid lipid nanoparticles (SLNs) that were converted into a gel for improved topical applications. The SLNs were prepared using a solvent evaporation method and characterized for their physicochemical properties. The particle size of the SLNs was in the range of 439 nm to 669 nm with a PDI of ≤0.4, indicating a monodispersed system. The Zeta potential of uncoated SLNs (F1–F5) ranged from −25.80 to −15.40 mV. Those values reverted to positive values for chitosan-decorated formulation (F6). The drug content and entrapment efficiency ranged between 0.86 ± 0.03 and 0.91 ± 0.03 mg/mL and 68.95 ± 0.03 and 83.68 ± 0.04%, respectively. The pH values of 5.45 to 5.53 depict their compatibility for skin application. The surface tension of the SLNs decreased with increasing surfactant concentration that could increase the adherence of the SLNs to the skin. The release of drug from gel formulations was significantly retarded in comparison to their corresponding SLN counterparts (p ≤ 0.05). Both SLNs and their corresponding gel achieved the same level of drug permeation, but the retention of the drug was significantly improved with the conversion of SLNs into their corresponding gel formulation (p ≤ 0.05) due to its higher bioadhesive properties.

Bioadhesive poly(methyl vinyl ether-co-maleic anhydride)-TPGS copolymer modified PLGA/lipid hybrid nanoparticles for improving intestinal absorption of cabazitaxel

A bioadhesive nanocarrier, PTNP, was constructed by utilizing a novel poly(methyl vinyl ether-co-maleic anhydride)- D-α-Tocopheryl polyethylene glycol succinate (PVMMA-TPGS) copolymer in the PLGA/lipid hybrid nanoparticles (PLGA NPs) for improving oral delivery of cabazitaxel (CTX). The PVMMA-TPGS was synthesized by the ring-opening polymerization of the anhydride groups with the hydroxyl groups, combining the bioadhesive property of PVMMA with P-glycoprotein (P-gp) inhibitory effect of TPGS. The CTX-loaded PTNPs (CTX-PTNPs) were prepared by an emulsification-solvent evaporation method and performed a spherical appearance with a uniform particle size of 192.2 nm. The CTX-PTNPs were surface negatively charged, and exhibited good drug loading (10.2%) and encapsulation efficiency (92.1%). A sustained drug release and high stability in simulated gastrointestinal environment were confirmed in in vitro studies. The in vitro mucin adhesion and in vivo intestinal retention experiments indicated that the PTNPs had a stronger bioadhesive effect and a notably longer intestinal retention than the control PLGA NPs, due to the interaction of PVMMA on the PTNP surface with the intestinal mucosa. Moreover, an enhanced intestinal permeability of the PTNPs was also verified in in vivo and ex vivo intestinal permeation studies, which was probably attributed to the extended retention of PTNPs in intestinal mucosa and the P-gp inhibitory effect of TPGS. As respected, in in vivo pharmacokinetic study, the T_max and oral bioavailability of CTX were dramatically improved to 1.08 h and 28.84% by the PTNPs, respectively, obviously superior to the CTX solution and the PLGA NPs, further demonstrating the high-efficiency in oral delivery of CTX. Hence, this bioadhesive carrier is proposed to be a potential and promising strategy for increasing oral absorption of small molecule insoluble drugs.

Tacrolimus encapsulated mesoporous silica nanoparticles embedded hydrogel for the treatment of atopic dermatitis

Atopic dermatitis (AD) is a repetitive inflammatory skin disorder with limited treatment options. Innovative targeted therapies are gaining significant interest and momentum towards disease control including better ways to deliver drugs topically. Tacrolimus is one such compound which is used to manage moderate to severe AD without causing atrophy which is one of the common side effects of steroids. However, Tacrolimus suffers from poor solubility and retention in the skin when used alone in hydrogel. Therefore, we have prepared Tacrolimus loaded mesoporous silica nanoparticles (TMSNs) to overcome the issues related to its solubility and effective topical delivery. Mesoporous silica nanoparticles (MSNs) were synthesized using sol gel technique and surface functionalized using amino (-NH₂⁺) and phosphonate (-PO₃^-) groups. Tacrolimus was loaded into MSNs and the particles were characterized for particle size (TEM and DLS), zeta potential (DLS), solubility studies, FTIR, TGA, XRD, BET and cytotoxicity studies. Water solubility of Tacrolimus was increased by 7 folds with phosphonate functionalized MSNs compared to free Tacrolimus. Further the TMSNs were incorporated in to carbopol gel, and the gel formulation was evaluated for various gel characterization tests (pH, spreadability, viscosity), in vitro tests (drug release, permeability studies) and in vivo tests (skin irritation study and efficacy studies) using 1-Fluoro-2,4-dinitrobenzene (DNFB) induced dermatitis in Balb/c mice. Results of in vitro and in vivo study showed that TMSNs loaded gel showed significantly higher amount of Tacrolimus retained (ex vivo - rat skin) and much higher reduction in ear thickness and improved histology (in vivo - in mice). Our data collectively suggest that MSNs incorporated hydrogel as a promising new formulation strategy for topical delivery of poorly soluble drugs.

Pharmaceutical Formulations with P-Glycoprotein Inhibitory Effect as Promising Approaches for Enhancing Oral Drug Absorption and Bioavailability

P-glycoprotein (P-gp) is crucial in the active transport of various substrates with diverse structures out of cells, resulting in poor intestinal permeation and limited bioavailability following oral administration. P-gp inhibitors, including small molecule drugs, natural constituents, and pharmaceutically inert excipients, have been exploited to overcome P-gp efflux and enhance the oral absorption and bioavailability of many P-gp substrates. The co-administration of small molecule P-gp inhibitors with P-gp substrates can result in drug–drug interactions and increased side effects due to the pharmacological activity of these molecules. On the other hand, pharmaceutically inert excipients, including polymers, surfactants, and lipid-based excipients, are safe, pharmaceutically acceptable, and are not absorbed from the gut. Notably, they can be incorporated in pharmaceutical formulations to enhance drug solubility, absorption, and bioavailability due to the formulation itself and the P-gp inhibitory effects of the excipients. Different formulations with inherent P-gp inhibitory activity have been developed. These include micelles, emulsions, liposomes, solid lipid nanoparticles, polymeric nanoparticles, microspheres, dendrimers, and solid dispersions. They can bypass P-gp by different mechanisms related to their properties. In this review, we briefly introduce P-gp and P-gp inhibitors, and we extensively summarize the current development of oral drug delivery systems that can bypass and inhibit P-gp to improve the oral absorption and bioavailability of P-gp substrates. Since many drugs are limited by P-gp-mediated efflux, this review is helpful for designing suitable formulations of P-gp substrates to enhance their oral absorption and bioavailability.

Lymphatic Transport of Drugs after Intestinal Absorption: Impact of Drug Formulation and Physicochemical Properties

PURPOSE

To provide a comprehensive and up-to-date overview focusing on the extent of lymphatic transport of drugs following intestinal absorption and to summarize available data on the impact of molecular weight, lipophilicity, formulation and prandial state.

METHODS

Literature was searched for in vivo studies quantifying extent of lymphatic transport of drugs after enteral dosing. Pharmacokinetic data were extracted and summarized. Influence of molecular weight, log P, formulation and prandial state was analyzed using relative bioavailability via lymph (F_RL) as the parameter for comparison. The methods and animal models used in the studies were also summarized.

RESULTS

Pharmacokinetic data on lymphatic transport were available for 103 drugs. Significantly higher F_RL [median (IQR)] was observed in advanced lipid based formulations [54.4% (52.0)] and oil solutions [38.9% (60.8)] compared to simple formulations [2.0% (27.1)], p < 0.0001 and p = 0.004, respectively. Advanced lipid based formulations also provided substantial F_RL in drugs with log P < 5, which was not observed in simple formulations and oil solutions. No relation was found between F_RL and molecular weight. There were 10 distinct methods used for in vivo testing of lymphatic transport after intestinal absorption so far.

CONCLUSION

Advanced lipid based formulations provide superior ability to increase lymphatic absorption in drugs of various molecular weights and in drugs with moderate to low lipophilicity.

Nanoformulation strategies for improving intestinal permeability of drugs: A more precise look at permeability assessment methods and pharmacokinetic properties changes

The therapeutic efficacy of orally administered drugs is often restricted by their inherent limited oral bioavailability. Low water solubility, limited permeability through the intestinal barrier, instability in harsh environment of the gastrointestinal (GI) tract and being substrate of the efflux pumps and the cytochrome P450 (CYP) can impair oral drug bioavailability resulting in erratic and variable plasma drug profile. As more drugs with low membrane permeability are developed, new interest is growing to enhance their intestinal permeability and bioavailability. A wide variety of nanosystems have been developed to improve drug transport and absorption. Sufficient evidence exists to suggest that nanoparticles are able to increase the transepithelial transport of drug molecules. However, key questions remained unanswered. What types of nanoparticles are more efficient? What are preclinical (or clinical) achievements of each type of nanoformulation in terms of pharmacokinetic (PK) parameters? Addressing this issue in this paper, we have reviewed the current literature regarding permeability enhancement, permeability assessment methods and changes in PK parameters following administration of various nanoformulations. Although permeability enhancement by various nanoformulations holds great promise for oral drug delivery, many challenges still need to be addressed before development of more clinically successful nanoproducts.

Co-encapsulation of docetaxel and cyclosporin A into SNEDDS to promote oral cancer chemotherapy

Self-nanoemulsifying drug delivery system (SNEDDS) have been considered as a promising platform for oral delivery of many BCS (biopharmaceutics classification system) class IV drugs, such as docetaxel (DTX). However, oral chemotherapy with DTX is also restricted by its active P-glycoprotein (P-gp) efflux and hepatic first-pass metabolism. To address these challenges, we developed a novel SNEDDS co-loaded with DTX and cyclosporine A (CsA) to achieve effective inhibition of P-gp efflux and P450 enzyme metabolization, improving oral bioavailability of DTX. The SNEDDS showed uniform droplet size of about 30 nm. Additionally, the prepared SNEDDS exhibited a sequential drug release trend of CsA prior to DTX. The intestinal experiments confirmed that the membrane permeability of DTX was significantly increased in the whole intestinal tract, especially in the jejunum segment. Furthermore, the oral bioavailability of co-loaded SNEDDS was 9.2-fold and 3.4-fold higher than DTX solution and DTX SNEDDS, respectively. More importantly, it exhibited a remarkable antitumor efficacy with a reduced toxicity compared with intravenously administered DTX solution. In summary, DTX-CsA co-loaded SNEDDS is a promising platform to facilitate oral docetaxel-based chemotherapy.

A Self-Nanoemulsifying Drug Delivery System for Enhancing the Oral Bioavailability of Candesartan Cilexetil: Ex Vivo and In Vivo Evaluation

The drug delivery of candesartan cilexetil encounters an obstacle of low absolute oral bioavailability which is attributed mainly to its low aqueous solubility and efflux by intestinal P-glycoprotein (P-gp) transporters. However, the extent of P-gp contribution in the reduced oral bioavailability of candesartan cilexetil is not clear. In this study, a previously developed candesartan cilexetil-loaded self-nanoemulsifying drug delivery system (SNEDDS) was evaluated for its ability to increase the drug oral bioavailability via the inhibition of intestinal P-gp transporters. Despite the developed SNEDDS showing P-gp inhibition activity, P-gp-mediated efflux was found to have a minor role in the reduced oral bioavailability of candesartan cilexetil. On the other hand, the high surfactant concentration used in SNEDDS formulation represents a major challenge toward their widespread application especially for chronically administered drugs. The designed acute and subacute toxicity studies revealed that the degree of intestinal mucosal damage decreases as the treatment period increases. The latter observation was attributed to the reversibility of surfactant-induced mucosal damage. Thus, the developed SNEDDS could be considered as a promising delivery system for enhancing the oral bioavailability of chronically administered drugs.

Preparation and evaluation of tacrolimus-loaded thermosensitive solid lipid nanoparticles for improved dermal distribution

Background: Tacrolimus (TCR), also known as FK-506, is a biopharmaceutics classification system (BCS) class II drug that is insoluble in water because of its high log P values. After dermal application, TCR remains in the stratum corneum and passes through the skin layers with difficulty.

Purpose: The objectives of this study were to develop and evaluate solid lipid nanoparticles (SLNs) with thermosensitive properties to improve penetration and retention.

Methods: We prepared TCR-loaded thermosensitive solid lipid nanoparticles (TCR-SLNs) with different types of surfactants on the shell of the particle, which conferred the advantages of enhancing skin permeation and distribution. We also characterized them from a physic point of view and performed in vitro and in vivo evaluations.

Results: The TCR contained in the prepared TCR-SLN was in an amorphous state and entrapped in the particles with a high loading efficiency. The assessment of ex vivo skin penetration using excised rat dorsal skin showed that the TCR-SLNs penetrated to a deeper layer than the reference product (0.1% Protopic^®). In addition, the in vivo skin penetration test demonstrated that TCR-SLNs delivered more drug into deeper skin layers than the reference product. FT-IR images also confirmed drug distribution of TCR-SLNs into deeper layers of the skin.

Conclusion: These results revealed the potential application of thermosensitive SLNs for the delivery of difficult-to-permeate, poorly water-soluble drugs into deep skin layers.

Formulating a single thioether-bridged oleate prodrug into a self-nanoemulsifying drug delivery system to facilitate oral absorption of docetaxel

Oral chemotherapy of docetaxel (DTX) is restricted by active P-glycoprotein (P-gp) efflux, hepatic first-pass metabolism and then poor oral absorption. Herein, a lipophilic thioether-bridged oleate prodrug (DTX-S-OA) and an ester-bond linked oleate prodrug of docetaxel (DTX-OA) were synthesized and efficiently incorporated into a self-nanoemulsifying drug delivery system (SNEDDS) using core-matching technology with a high drug-loading rate. DTX-S-OA SNEDDS produced a uniform droplet size of about 30 nm and a significantly high drug loading capability (60 mg mL-1), compared with DTX SNEDDS (20 mg mL-1). Additionally, DTX-S-OA SNEDDS exhibited a markedly slower drug release property and higher (>2-fold) drug solubilization in the aqueous phase after 60 min lipolysis compared with DTX SNEDDS. In situ single-pass intestinal perfusion and intestinal biodistribution studies demonstrated that the membrane permeability and intestinal bioadhesion of SNEDDS were significantly increased. Moreover, DTX-S-OA showed a comparable ability with verapamil in inhibiting P-gp efflux. Lymphatic transport studies confirmed that DTX-S-OA SNEDDS could significantly enhance intestinal lymphatic transport. Notably, the bioavailability of DTX-S-OA SNEDDS was 6.2-fold and 2.0-fold higher than that of the DTX solution and DTX SNEDDS, respectively. Furthermore, DTX-S-OA achieved a more rapid release of free DTX from the prodrug in systemic circulation than DTX-OA. Therefore, such a unique combination strategy of the single thioether-bridged DTX-oleate prodrug and SNEDDS is a promising platform to enable effective oral delivery of DTX.

In vivo tailor-made protein corona of a prodrug-based nanoassembly fabricated by redox dual-sensitive paclitaxel prodrug for the superselective treatment of breast cancer

Prodrug self-nanoassemblies have many advantages for anticancer drug delivery, including high drug loading rate, resistance to recrystallization, and on-demand drug release. However, few studies have focused on their protein corona, which is inevitably formed after entering the blood and determines their subsequent fates in vivo. To actively tune the protein corona of prodrug nanoassemblies, three maleimide-paclitaxel prodrugs were synthesized via different redox-sensitive linkers (ester bond, thioether bond and disulfide bond). After incubation with rat plasma, the surface maleimide groups effectively captured albumins, resulting in albumin-enriched protein corona. The recruited albumin corona enabled enhanced tumor accumulation and facilitated cellular uptake, ensuring the high-efficiency delivery of nanoassemblies to tumor cells. Surprisingly, we found that the traditionally reduction-sensitive disulfide bond could also be triggered by reactive oxygen species (ROS). Such a redox dual-responsive drug release property of the disulfide bond-containing prodrug nanoassemblies further increased the selectivity in cytotoxicity between normal and tumor cells. Moreover, the disulfide bond-containing prodrug nanoassemblies exhibited the highest antitumor efficacy in vivo compared to marketed Abraxane® and other prodrug nanoassemblies. Thus, the fabrication of the maleimide-decorated disulfide bond bridged prodrug nanoassembly, integrating a tunable protein corona and on-demand drug release, is a promising strategy for improved cancer chemotherapy.

Cyclodextrin-grafted poly(anhydride) nanoparticles for oral glibenclamide administration. In vivo evaluation using C. elegans

The aim of this work was to prepare and evaluate cyclodextrins-modified poly(anhydride) nanoparticles to enhance the oral administration of glibenclamide. A conjugate polymer was synthesized by incorporating hydroxypropyl-β-cyclodextrin to the backbone of poly(methylvinyl ether-co-maleic anhydride) via Steglich reaction. The degree of substitution of anhydride rings by cyclodextrins molecules was calculated to be 4.9% using H-NMR spectroscopy. A central composite design of experiments was used to optimize the preparative process. Under the optimal conditions, nanoparticles displayed a size of about 170 nm, a surface charge of -47 mV and a drug loading of 69 µg GB/mg. X-ray diffraction studies confirmed the loss of the crystalline structure of GB due to its dispersion into the nanoparticles, either included into cyclodextrin cavities or entrapped in the polymer chains. Glibenclamide was mainly release by Fickian-diffusion in simulated intestinal fluid. GB-loaded nanoparticles produced a hypolipidemic effect over C. elegans N2 wild-type and daf-2 mutant. The action mechanism included daf-2 and daf-28 genes, both implicated in the insulin signaling pathway of C. elegans. In summary, the covalent linkage of cyclodextrin to the poly(anhydride) backbone could be an interesting strategy to prepare nanoparticles for the oral administration of glibenclamide.

Poly(vinyl methyl ether/maleic anhydride)-Doped PEG-PLA Nanoparticles for Oral Paclitaxel Delivery To Improve Bioadhesive Efficiency

Bioadhesive nanoparticles based on poly(vinyl methyl ether/maleic anhydride) (PVMMA) and poly(ethylene glycol) methyl ether-b-poly(d,l-lactic acid) (mPEG-b-PLA) were produced by the emulsification solvent evaporation method. Paclitaxel was utilized as the model drug, with an encapsulation efficiency of up to 90.2 ± 4.0%. The nanoparticles were uniform and spherical in shape and exhibited a sustained drug release compared with Taxol. m-NPs also exhibited favorable bioadhesive efficiency at the same time. Coumarin 6 or DiR-loaded nanoparticles with/without PVMMA (C6-m-NPs/DiR-m-NPs or C6-p-NPs/DiR-p-NPs) were used for cellular uptake and intestinal adhesion experiments, respectively. C6-m-NPs were shown to enhance cellular uptake, and caveolae/lipid raft mediated endocytosis was the primary route for the uptake of the nanoparticles. Favorable bioadhesive efficiency led to prolonged retention in the intestine reflected by the fluorescence in isolated intestines ex vivo. In a ligated intestinal loops model, C6-m-NPs showed a clear advantage for transporting NPs across the mucus layer over C6-p-NPs and free C6. The apparent permeability coefficient (Papp) of PTX-m-NPs through Caco-2/HT29 monolayers was 1.3- and 1.6-fold higher than PTX-p-NPs and Taxol, respectively, which was consistent with the AUC_0-t of different PTX formulations after oral administration in rats. PTX-m-NPs also exhibited a more effective anticancer efficacy, with an IC₅₀ of 0.2 ± 1.4 μg/mL for A549 cell lines, further demonstrating the advantage of bioadhesive nanoparticles. The bioadhesive nanoparticles m-NPs demonstrated both mucus permeation and epithelial absorption, and thus, this bioadhesive drug delivery system has the potential to improve the bioavailability of drugs that are insoluble in the gastrointestinal environment.

The Poly(acrylonitrule-co-acrylic acid)-graft-β-cyclodextrin Hydrogel for Thorium(IV) Adsorption

In this report, the β-CD(AN-co-AA) hydrogel was used to remove the thorium(IV) [Th(IV)] from the water system, and the new adsorbent was characterized through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The influences of contact time, pH value, ionic strength, solid-liquid ratio, initial Th(IV) concentration, and temperature on Th(IV) adsorption onto the functional hydrogel were researched. The results showed that the experimental data followed the Langmuir isotherm and the maximum adsorption capacity (q_max) for Th(IV) was 692 mg/g at pH 2.95, which approached the calculated (q_e) 682 mg/g. The desorption capacity of Th(IV) in different HNO₃ concentrations ranging from 0.005 to 0.5 M was also studied, and the percentage of the maximum desorption was 86.85% in the condition of 0.09 M HNO₃. The selectivity of β-CD(AN-co-AA) hydrogel was also be studied, the results indicated that this material retained the good adsorption capacity to Th(IV) even when the Ca²⁺, Mg²⁺, or Pb²⁺ existed in the system. The findings indicate that β-CD(AN-co-AA) can be used as a new candidate for the enrichment and separation of Th(IV), or its analogue actinides, from large-volume solution in practical application.

Nanotechnology in Glycomics: Applications in Diagnostics, Therapy, Imaging, and Separation Processes

This review comprehensively covers the most recent achievements (from 2013) in the successful integration of nanomaterials in the field of glycomics. The first part of the paper addresses the beneficial properties of nanomaterials for the construction of biosensors, bioanalytical devices, and protocols for the detection of various analytes, including viruses and whole cells, together with their key characteristics. The second part of the review focuses on the application of nanomaterials integrated with glycans for various biomedical applications, that is, vaccines against viral and bacterial infections and cancer cells, as therapeutic agents, for in vivo imaging and nuclear magnetic resonance imaging, and for selective drug delivery. The final part of the review describes various ways in which glycan enrichment can be effectively done using nanomaterials, molecularly imprinted polymers with polymer thickness controlled at the nanoscale, with a subsequent analysis of glycans by mass spectrometry. A short section describing an active glycoprofiling by microengines (microrockets) is covered as well.

In vitro evaluation of the genotoxicity of poly(anhydride) nanoparticles designed for oral drug delivery

In the last years, the development of nanomaterials has significantly increased due to the immense variety of potential applications in technological sectors, such as medicine, pharmacy and food safety. Focusing on the nanodevices for oral drug delivery, poly(anhydride) nanoparticles have received extensive attention due to their unique properties, such as their capability to develop intense adhesive interactions within the gut mucosa, their modifiable surface and their biodegradable and easy-to-produce profile. However, current knowledge of the possible adverse health effects as well as, toxicological information, is still exceedingly limited. Thus, we investigated the capacity of two poly(anhydride) nanoparticles, Gantrez^® AN 119-NP (GN-NP) and Gantrez^® AN 119 covered with mannosamine (GN-MA-NP), and their main bulk material (Gantrez^® AN 119-Polymer), to induce DNA damage and thymidine kinase (TK^+/-) mutations in L5178Y TK^+/- mouse lymphoma cells after 24h of exposure. The results showed that GN-NP, GN-MA-NP and their polymer did not induce DNA strand breaks or oxidative damage at concentrations ranging from 7.4 to 600μg/mL. Besides, the mutagenic potential of these nanoparticles and their polymer revealed no significant or biologically relevant gene mutation induction at concentrations up to 600μg/mL under our experimental settings. Considering the non-genotoxic effects of GN-NP and GN-MA-NP, as well as their exceptional properties, these nanoparticles are promising nanocarriers for oral medical administrations.

Development of novel self-assembled ES-PLGA hybrid nanoparticles for improving oral absorption of doxorubicin hydrochloride by P-gp inhibition: In vitro and in vivo evaluation

To increase the encapsulation efficiency and oral absorption of doxorubicin hydrochloride (DOX), a novel drug delivery system of enoxaparin sodium-PLGA hybrid nanoparticles (EPNs) was successfully designed. By introducing the negative polymer of enoxaparin sodium (ES) to form an electrostatic complex with the cationic drug, DOX, the encapsulation efficiency (93.78%) of DOX was significantly improved. The X-ray diffraction (XRD) results revealed that the DOX-ES complex was in an amorphous form. An in vitro release (pH6.8 PBS) study showed the excellent sustained-release characteristics of DOX-loaded EPNs (DOX-EPNs). In addition, in situ intestinal perfusion and intestinal biodistribution experiments demonstrated the improved membrane permeability and intestinal wall bioadhesion of DOX-EPNs, and caveolin- and clathrin-mediated endocytosis pathways were the main mechanisms responsible. The cytotoxicity of DOX was significantly increased by EPNs in Caco-2 cells, compared with DOX-Sol. Confocal laser scanning microscope (CLSM) images confirmed that the amount of DOX-EPNs internalized by Caco-2 cells was higher than that of DOX-Sol showing that P-glycoprotein-mediated drug efflux was reduced by the introduction of EPNs. The qualitative detection of transcytosis demonstrated the ability of the nanoparticles (NPs) to cross Caco-2 cell monolayers. An in vivo toxicity experiment demonstrated that DOX-EPNs reduced cardiac and renal toxic effects and were biocompatible. An in vivo pharmacokinetics study showed that the AUC_(0-t) and t_1/2 of DOX-EPNs were increased to 3.63-fold and 2.47-fold in comparison with DOX solution (DOX-Sol), respectively. All these results indicated that the novel EPNs were an excellent platform to improve the encapsulation efficiency of an aqueous solution of this antitumor drug and its oral bioavailability.

Development of Liposome containing sodium deoxycholate to enhance oral bioavailability of itraconazole

The aim of this study was to enhance oral bioavailability of itraconazole (ITZ) by developing Liposome containing sodium deoxycholate (ITZ-Lip-NaDC). The liposome, consisting of egg yolk lecithin and sodium deoxycholate, was prepared by thin-film dispersion method. Differential Scanning Calorimetry (DSC) results indicated an amorphous state in the liposome. The physicochemical characteristics including particle size, morphology, entrapment efficiency, dissolution properties were also investigated. The performance of single-pass intestinal infusion exhibited that the transport order of intestinal segment was jejunum, duodenum, colon and ileum, and that all the segments participated in the absorption of ITZ in intestinal tract. The bioavailability study in rats showed that the AUC_0-72 of the liposome was nearly 1.67-fold higher than that of commercial capsules (SPORANOX) in terms of oral administration, and the RSD of AUC_0-72 of ITZ-Lip-NaDC was also decreased. Our results indicated that ITZ-Lip-NaDC liposome was facilitated to improve dissolution efficiency, augment transmembrane absorption, and then enhance the oral bioavailability of ITZ, successfully.

Luteinizing hormone-releasing hormone targeted poly(methyl vinyl ether maleic acid) nanoparticles for doxorubicin delivery to MCF-7 breast cancer cells

The purpose of this study was to design a targeted anti-cancer drug delivery system for breast cancer. Therefore, doxorubicin (DOX) loaded poly(methyl vinyl ether maleic acid) nanoparticles (NPs) were prepared by ionic cross-linking method using Zn(2+) ions. To optimise the effect of DOX/polymer ratio, Zn/polymer ratio, and stirrer rate a full factorial design was used and their effects on particle size, zeta potential, loading efficiency (LE, %), and release efficiency in 72 h (RE72, %) were studied. Targeted NPs were prepared by chemical coating of tiptorelin/polyallylamin conjugate on the surface of NPs by using 1-ethyl-3-(3-dimethylaminopropyl) carboiimid HCl as cross-linking agent. Conjugation efficiency was measured by Bradford assay. Conjugated triptorelin and targeted NPs were studied by Fourier-transform infrared spectroscopy (FTIR). The cytotoxicity of DOX loaded in targeted NPs and non-targeted ones were studied on MCF-7 cells which overexpress luteinizing hormone-releasing hormone (LHRH) receptors and SKOV3 cells as negative LHRH receptors using Thiazolyl blue tetrazolium bromide assay. The best results obtained from NPs prepared by DOX/polymer ratio of 5%, Zn/polymer ratio of 50%, and stirrer rate of 960 rpm. FTIR spectrum confirmed successful conjugation of triptorelin to NPs. The conjugation efficiency was about 70%. The targeted NPs showed significantly less IC50 for MCF-7 cells compared to free DOX and non-targeted NPs.

Improved oral bioavailability of docetaxel by nanostructured lipid carriers: in vitro characteristics, in vivo evaluation and intestinal transport studies

The objective of the current study was to explore the potential of nanostructured lipid carriers (NLC) for oral delivery of docetaxel (DTX) and investigate the absorption mechanismin vivo.