Enhanced oral absorption and anticancer efficacy of cabazitaxel by overcoming intestinal mucus and epithelium barriers using surface polyethylene oxide (PEO) decorated positively charged polymer-lipid hybrid nanoparticles

β-Glucan-A promising immunocyte-targeting drug delivery vehicle: Superiority, applications and future prospects

Drug delivery technologies that could convert promising therapeutics into successful therapies have been under broad research for many years. Recently, β-glucans, natural-occurring polysaccharides extracted from many organism species such as yeast, fungi and bacteria, have attracted increasing attention to serve as drug delivery carriers. With their unique structure and innate immunocompetence, β-glucans are considered as promising carriers for targeting delivery especially when applied in the vaccine construction and oral administration of therapeutic agents. In this review, we focus on three types of β-glucans applied in the drug delivery system including yeast β-glucan, Schizophyllan and curdlan, highlighting the benefits of β-glucan based delivery system. We summarize how β-glucans as delivery vehicles have aided various therapeutics ranging from macromolecules including proteins, peptides and nucleic acids to small molecular drugs to reach desired cells or organs in terms of loading strategies. We also outline the challenges and future directions for developing the next generation of β-glucan based delivery systems.

Oral nanomedicine biointeractions in the gastrointestinal tract in health and disease

Oral administration is the preferred route of administration based on the convenience for and compliance of the patient. Oral nanomedicines have been developed to overcome the limitations of free drugs and overcome gastrointestinal (GI) barriers, which are heterogeneous across healthy and diseased populations. This review aims to provide a comprehensive overview and comparison of the oral nanomedicine biointeractions in the gastrointestinal tract (GIT) in health and disease (GI and extra-GI diseases) and highlight emerging strategies that exploit these differences for oral nanomedicine-based treatment. We introduce the key GI barriers related to oral delivery and summarize their pathological changes in various diseases. We discuss nanomedicine biointeractions in the GIT in health by describing the general biointeractions based on the type of oral nanomedicine and advanced biointeractions facilitated by advanced strategies applied in this field. We then discuss nanomedicine biointeractions in different diseases and explore how pathological characteristics have been harnessed to advance the development of oral nanomedicine.

Topical Drug Delivery of Concentrated Cabazitaxel in an α-Tocopherol and DMSO Solution

Topical chemotherapy approaches are relevant for certain skin cancer treatments. This study observes that cabazitaxel (CTX), a broad-spectrum second-generation taxane cytotoxic agent, can be dissolved in α-tocopherol at high concentrations exceeding 100 mg mL-1 . 2D nuclear magnetic resonance (NMR) analysis and molecular dynamics (MD) are used to study this phenomenon. The addition of 30% dimethyl sulfoxide (DMSO) to the α-tocopherol/CTX solution improves its working viscosity and enhances CTX permeation through human skin in vitro (over 5 µg cm-2 within 24 h), while no detectable drug permeates when CTX is dissolved in α-tocopherol alone. In a transepidermal water loss assay, the barrier impairment induced by CTX in 30% DMSO in α-tocopherol, but not in pure DMSO, is reversible 8 h after the formulation removal from the skin surface. Antitumor efficacy of the topical CTX formulation is evaluated in nude mice bearing A431 human squamous carcinoma skin cancer xenografts. With topical application of concentrated CTX solutions (75 mg mL-1 ), tumor growth is significantly suppressed compared to lower concentration groups (0, 25, or 50 mg mL-1 CTX). Taken together, these findings show that topical delivery of CTX using a DMSO and α-tocopherol solvent warrants further study as a treatment for skin malignancies.

A multifunctional integrated biomimetic spore nanoplatform for successively overcoming oral biological barriers

The biological barriers have seriously restricted the efficacious responses of oral delivery system in diseases treatment. Utilizing a carrier based on the single construction means is hard to overcome these obstacles simultaneously because the complex gastrointestinal tract environment requires carrier to have different or even contradictory properties. Interestingly, spore capsid (SC) integrates many unique biological characteristics, such as high resistance, good stability etc. This fact offers a boundless source of inspiration for the construction of multi-functional oral nanoplatform based on SC without further modification. Herein, we develop a type of biomimetic spore nanoplatform (SC@DS NPs) to successively overcome oral biological barriers. Firstly, doxorubicin (DOX) and sorafenib (SOR) are self-assembled to form carrier-free nanoparticles (DS NPs). Subsequently, SC is effectively separated from probiotic spores and served as a functional vehicle for delivering DS NPs. As expect, SC@DS NPs can efficaciously pass through the rugged stomach environment after oral administration and further be transported to the intestine. Surprisingly, we find that SC@DS NPs exhibit a significant improvement in the aspects of mucus penetration and transepithelial transport, which is related to the protein species of SC. This study demonstrates that SC@DS NPs can efficiently overcome multiple biological barriers and improve the therapeutic effect.

Modulation of engineered nanomaterial interactions with organ barriers for enhanced drug transport

The biomedical use of nanoparticles (NPs) has been the focus of intense research for over a decade. As most NPs are explored as carriers to alter the biodistribution, pharmacokinetics and bioavailability of associated drugs, the delivery of these NPs to the tissues of interest remains an important topic. To date, the majority of NP delivery studies have used tumor models as their tool of interest, and the limitations concerning tumor targeting of systemically administered NPs have been well studied. In recent years, the focus has also shifted to other organs, each presenting their own unique delivery challenges to overcome. In this review, we discuss the recent advances in leveraging NPs to overcome four major biological barriers including the lung mucus, the gastrointestinal mucus, the placental barrier, and the blood-brain barrier. We define the specific properties of these biological barriers, discuss the challenges related to NP transport across them, and provide an overview of recent advances in the field. We discuss the strengths and shortcomings of different strategies to facilitate NP transport across the barriers and highlight some key findings that can stimulate further advances in this field.

Bioactive fatty acid analog-derived hybrid nanoparticles confer antibody-independent chemo-immunotherapy against carcinoma

Typical chemo-immunotherapy against malignant carcinoma, is characterized by the combined application of chemotherapeutic agents and monoclonal antibodies for immune checkpoint blockade (ICB). Temporary ICB with antibodies would not depress tumor intrinsic PD-L1 expression and potential PD-L1 adaptive upregulation during chemotherapy, thus exerting limited immunotherapy efficacy. Herein, we developed novel polymer-lipid hybrid nanoparticles (2-BP/CPT-PLNs) for inducing PD-L1 degradation by inhibiting palmitoylation with bioactive palmitic acid analog 2-bromopalmitate (2-BP) to replace PD-L1 antibody (αPD-L1) for ICB therapy, thus achieving highly efficient antitumor immune via immunogenic cell death (ICD) induced by potentiated chemotherapy. GSH-responsive and biodegradable polymer-prodrug CPT-ss-PAEEP₁₀ assisted as a cationic helper polymer could help to stabilize 2-BP/CPT-PLNs co-assembled with 2-BP, and facilitate the tumor site-specific delivery and intracellular release of water-insoluble camptothecin (CPT) in vivo. 2-BP/CPT-PLNs would reinforce cytotoxic CD8⁺ T cell-mediated antitumor immune response via promoting intratumoral lymphocytes cells infiltration and activation. 2-BP/CPT-PLNs significantly prevented melanoma progression and prolonged life survival of mice beyond the conventional combination of irinotecan hydrochloride (CPT-11) and αPD-L1. Our work first provided valuable instructions for developing bioactive lipid analogs-derived nanoparticles via lipid metabolism intervention for oncotherapy.

Fabrication of a Polysaccharide-Protein/Protein Complex Stabilized Oral Nanoemulsion to Facilitate the Therapeutic Effects of 1,8-Cineole on Atherosclerosis

Atherosclerosis (AS) is a systemic disease characterized by lipid deposition in the blood vessel wall that urgently requires effective and safe therapeutic drugs for long-term treatment. An essential oil monomer-1,8-cineole (CIN) with ameliorative effects on vascular injuries has considerable potential for preventing the progression of AS because of its antioxidant, anti-inflammation, and cholesterol regulatory effects. However, the high volatility and instability of CIN result in low oral bioavailability and a short half-life, thereby limiting its clinical application. We formulated a nanoemulsion using a polysaccharide-protein/protein complex (dextran-bovine serum albumin/protamine, DEX_5k-BSA/PTM) as an emulsifier, with vitamin B12 (VB₁₂) as the ligand to facilitate the transportation across the small intestine. An emulsion preparation method using a microjet followed by ultraviolet irradiation was developed to obtain the CIN-loaded oral nanoemulsion CIN@DEX_5k-BSA/PTM/VB₁₂. The nanoemulsion improved the stability of CIN both in vitro and in vivo, prolonged the retention time in the gastrointestinal tract (GIT), and enhanced the permeability across the mucus layer and intestinal epithelial cells to increase oral bioavailability and plaque accumulation of CIN. Validated in an AS mouse model, CIN@DEX_5k-BSA/PTM/VB₁₂ achieved prominent therapeutic efficacy combating AS. This study highlights the advantages of DEX_5k-BSA/PTM and VB₁₂ in the development of nanoemulsions for CIN and provides a promising oral nanoplatform for the delivery of essential oils.

Surface design of nanocarriers: Key to more efficient oral drug delivery systems

As nanocarriers (NCs) can improve the solubility of drugs, prevent their degradation by gastrointestinal (GI) enzymes and promote their transport across the mucus gel layer and absorption membrane, the oral bioavailability of these drugs can be substantially enhanced. All these properties of NCs including self-emulsifying drug delivery systems (SEDDS), solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), liposomes, polymeric nanoparticles, inorganic nanoparticles and polymeric micelles depend mainly on their surface chemistry. In particular, interaction with food, digestive enzymes, bile salts and electrolytes, diffusion behaviour across the mucus gel layer and fate on the absorption membrane are determined by their surface. Bioinert surfaces limiting interactions with gastrointestinal fluid and content as well as with mucus, adhesive surfaces providing an intimate contact with the GI mucosa and absorption enhancing surfaces can be designed. Furthermore, charge converting surfaces shifting their zeta potential from negative to positive directly at the absorption membrane and surfaces providing a targeted drug release are advantageous. In addition to these passive surfaces, even active surfaces cleaving mucus glycoproteins on their way through the mucus gel layer can be created. Within this review, we provide an overview on these different surfaces and discuss their impact on the performance of NCs in the GI tract.

Current development of cabazitaxel drug delivery systems

The second-generation taxane cabazitaxel has been clinically approved for the treatment of metastatic castration-resistant prostate cancer after docetaxel failure. Compared with the first-generation taxanes paclitaxel and docetaxel, cabazitaxel has potent anticancer activity and is less prone to drug resistance due to its lower affinity for the P-gp efflux pump. The relatively high hydrophobicity of cabazitaxel and the poor aqueous colloidal stability of the commercial formulation, following its preparation for injection, presents opportunities for new cabazitaxel formulations with improved features. This review provides an overview of cabazitaxel drug formulations and hydrophobic taxane drug delivery systems in general, and particularly focuses on emerging cabazitaxel delivery systems discovered in the past 5 years. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Mesoporous silica nanoparticles with chiral pattern topological structure function as “antiskid tires” on the intestinal mucosa to facilitate oral drugs delivery

The weak adhesion between nanocarriers and the intestinal mucosa was one of the main reasons caused the failure in oral delivery. Inspired by the "antiskid tires" with complex chiral patterns, mesoporous silica nanoparticles AT-R@CMSN exhibiting geometrical chiral structure were designed to improve the surface/interface roughness in nanoscale, and employed as the hosting system for insoluble drugs nimesulide (NMS) and ibuprofen (IBU). Once performing the delivery tasks, AT-R@CMSN with rigid skeleton protected the loaded drug and reduced the irritation of drug on gastrointestinal tract (GIT), while their porous structure deprived drug crystal and improved drug release. More importantly, AT-R@CMSN functioned as "antiskid tire" to produce higher friction on intestinal mucosa and substantively influenced multiple biological processes, including "contact", "adhesion", "retention", "permeation" and "uptake", compared to the achiral S@MSN, thereby improving the oral adsorption effectiveness of such drug delivery systems. By engineering AT-R@CMSN to overcome the stability, solubility and permeability bottlenecks of drugs, orally administered NMS or IBU loaded AT-R@CMSN could achieve higher relative bioavailability (705.95% and 444.42%, respectively) and stronger anti-inflammation effect. In addition, AT-R@CMSN displayed favorable biocompatibility and biodegradability. Undoubtedly, the present finding helped to understand the oral adsorption process of nanocarriers, and provided novel insights into the rational design of nanocarriers.

Physicochemical properties, pharmacokinetics, toxicology and application of nanocarriers

As a promising delivery nanosystem for drug controlled-release, nanocarriers (NCs) have been investigated widely. Although various studies have concentrated on the preparation and characterization of nanoparticles (NPs), clinical applications are rarely reported, due to the unclear distribution, absorption, metabolism, toxicology processes and drug release mechanism. The clinical application of NCs is therefore still a long way off. This review describes the effects of the properties of NCs (including size, shape, surface properties, porosity, elasticity and so on) on pharmacological and toxicological behaviours in vivo and medical applications. Moreover, this study is intended to help the readers understand the behaviours and mechanisms of NCs and positively face the challenges caused by the variety of complicated and limited processes of NCs in vivo. Importantly, this article provides some strategies for the clinical application of NCs and may provide ideas to enhance the therapeutic efficacy of NCs without increasing the toxicology, by introducing tracing technology, which can be more suitable in contributing to the development of safety and efficacy of NCs and the growth of nanotechnology.

A lymphatic-absorbed multi-targeted kinase inhibitor for myelofibrosis therapy

Activation of compensatory signaling nodes in cancer often requires combination therapies that are frequently plagued by dose-limiting toxicities. Intestinal lymphatic drug absorption is seldom explored, although reduced toxicity and sustained drug levels would be anticipated to improve systemic bioavailability. A potent orally bioavailable multi-functional kinase inhibitor (LP-182) is described with intrinsic lymphatic partitioning for the combined targeting of phosphoinositide 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways without observable toxicity. We demonstrate selectivity and therapeutic efficacy through reduction of downstream kinase activation, amelioration of disease phenotypes, and improved survival in animal models of myelofibrosis. Our further characterization of synthetic and physiochemical properties for small molecule lymphatic uptake will support continued advancements in lymphatropic therapy for altering disease trajectories of a myriad of human disease indications.

Combination therapies simultaneously inhibiting different therapeutic targets in cancer is challenged by individual pharmacokinetic profiles. Here, the authors generate an orally provided multi-targeted kinase inhibitor that is lymphatic absorbed and increases survival in a murine model of myelofibrosis.

Glucose-Modified Zein Nanoparticles Enhance Oral Delivery of Docetaxel

Based on glucose (G) transporters (GLUTs), structuring nanoparticles with G as a target are an effective strategy to enhance oral bioavailability and anti-tumor effects of drugs. A novel drug delivery system using G-modified zein (GZ) nanoparticles loaded with docetaxel (DTX) (DTX-GNPs) was prepared and characterized in vitro and in vivo via assessment of cellular uptake, absorption site, pharmacokinetics, ex vivo distribution, and anti-tumor effects. The DTX-GNPs were approximately 120 nm in size. Compared with DTX-NPs, G modification significantly enhanced cellular uptake of DTX-GNPs by 1.22 times in CaCo-2 cells, which was related to GLUT mediation and the enhancement of endocytosis pathways via clathrin, micropinocytosis, and caveolin. Compared to DTX-NPs, G modification significantly enhanced DTX-NP absorption in the jejunum and ileum, delayed plasma concentration peak time, prolonged the average residence time in vivo, and increased oral bioavailability (from 43.82% to 96.04%). Cellular uptake and oral bioavailability of DTX were significantly affected by the G modification ratio. Compared with DTX-NPs, G modification significantly reduced drug distribution in the liver, lungs, and kidneys and increased tumor distribution and tumor growth inhibition rate without obvious systemic toxicity. This study demonstrated the potential of GZ-NPs as nanocarriers for DTX to enhance oral bioavailability and anti-tumor effects.

Preclinical Validation of a Novel Injection-Molded Swab for the Molecular Assay Detection of SARS-CoV-2

During the COVID-19 public health emergency, many actions have been undertaken to help ensure that patients and health care providers have timely and continued access to high-quality medical devices to respond effectively. The development and validation of new testing supplies and equipment, including collection swabs, has helped to expand the availability and capability for various diagnostic, therapeutic, and protective medical devices in high demand during the COVID-19 emergency. Here, we report the initial validation of a new injection-molded anterior nasal swab, ClearTip™, that was experimentally validated in a laboratory setting as well as in independent clinical studies in comparison to gold standard flocked swabs. We have also developed an in vitro anterior nasal tissue model which offers a novel, efficient, and clinically relevant validation tool to replicate the clinical swabbing workflow with high fidelity, while being accessible, safe, reproducible, and time- and cost-effective. ClearTip™ displayed greater inactivated virus release in the benchtop model, confirmed by its greater ability to report positive samples in a small clinical study in comparison to flocked swabs. We also quantified the detection of biological materials, as a proxy for viral material, in multi-center pre-clinical and clinical studies which showed a statistically significant difference in one study and a reduction in performance in comparison to flocked swabs. Taken together, these results emphasize the compelling benefits of non-absorbent injection-molded anterior nasal swabs for COVID-19 detection, comparable to standard flocked swabs. Injection-molded swabs, as ClearTip™, could have the potential to support future swab shortages, due to its manufacturing advantages, while offering benefits in comparison to highly absorbent swabs in terms of comfort, limited volume collection, and potential multiple usage.

Synthesis and Validation of a Bioinspired Catechol-Functionalized Pt(IV) Prodrug for Preclinical Intranasal Glioblastoma Treatment

Simple Summary

Glioblastoma (GB) is a type of brain cancer with a poor prognosis and few improvements in its treatment. One of the greatest difficulties in GB therapy lies in the fact that most of the drugs with high anticancer potential do not reach the brain and exert high therapeutic activity while minimizing side effects. To overcome these limitations, we focused on a catechol-based Pt(IV) prodrug (able to reverse cisplatin in a cellular environment) with the intention of repurposing Pt-based drugs as GB chemotherapeutic agents. Our in vitro results have corroborated the therapeutic effect of the synthesized complexes as comparable to cisplatin, and in vivo studies have demonstrated the potential of nose-to-brain delivery of this Pt(IV) prodrug for GB treatment.

Abstract

Glioblastoma is the most malignant and frequently occurring type of brain tumors in adults. Its treatment has been greatly hampered by the difficulty to achieve effective therapeutic concentration in the tumor sites due to its location and the blood–brain barrier. Intranasal administration has emerged as an alternative for drug delivery into the brain though mucopenetration, and rapid mucociliary clearance still remains an issue to be solved before its implementation. To address these issues, based on the intriguing properties of proteins secreted by mussels, polyphenol and catechol functionalization has already been used to promote mucopenetration, intranasal delivery and transport across the blood–brain barrier. Thus, herein we report the synthesis and study of complex 1, a Pt(IV) prodrug functionalized with catecholic moieties. This complex considerably augmented solubility in contrast to cisplatin and showed a comparable cytotoxic effect on cisplatin in HeLa, 1Br3G and GL261 cells. Furthermore, preclinical in vivo therapy using the intranasal administration route suggested that it can reach the brain and inhibit the growth of orthotopic GL261 glioblastoma. These results open new opportunities for catechol-bearing anticancer prodrugs in the treatment for brain tumors via intranasal administration.

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.

A common strategy to improve transmembrane transport in polarized epithelial cells based on sorting signals: Guiding nanocarriers to TGN rather than to the basolateral plasma membrane directly

The intestinal barrier has always been the rate-limiting step in the oral administration process. To overcome the intestinal barrier, researchers have widely adopted nanocarriers, especially active-targeting nanocarriers strategies. However, most of these strategies focus on the ligand decoration of nanocarriers targeting specific receptors, so their applications are confined to specific receptors or specific cell types. In this study, we tried to investigate more common strategies in the field of transmembrane transport enhancement. Trans-Golgi network (TGN) is the sorting center of biosynthetic route which could achieve polarized localization of proteins in polarized epithelial cells, and the basolateral plasma membrane is where all transcytotic cargos have to pass through. Thus, it is expected that guiding nanocarriers to TGN or basolateral plasma membrane may improve the transcytosis. Hence, we choose sorting signal peptide to modify micelles to guide micelles to TGN (named as BAC decorated micelles, BAC-M) or to basolateral plasma membrane (named as STX decorated micelles, STX-M). By incorporating coumarin-6 (C6) or Cy5-PEG-PCL in the micelles to indicate the behavior of micelles, the effects of these two strategies on the transcytosis were investigated. To our surprise, BAC-M and STX-M behaved quite differently when crossing biological barriers. BAC-M showed significant superiority in colocalization with TGN, transmembrane transport and even in vivo absorption, while STX-M had no significant difference from blank micelles. Further investigation revealed that the strategy of directly guiding nanocarriers to the basolateral plasma membrane (STX-M) only caused the stack of vesicles near the basolateral plasma membrane. So, we concluded that guiding nanocarriers to TGN which related to secretion may contribute to the transmembrane transport. This common strategy based on the physiological function of TGN in polarized epithelial cells will have broad application prospects in overcoming biological barrier.

Nanomedicine for increasing the oral bioavailability of cancer treatments

Abstract

Oral administration is an appealing route of delivering cancer treatments. However, the gastrointestinal tract is characterized by specific and efficient physical, chemical, and biological barriers that decrease the bioavailability of medications, including chemotherapeutics. In recent decades, the fields of material science and nanomedicine have generated several delivery platforms with high potential for overcoming multiple barriers associated to oral administration. This review describes the properties of several nanodelivery systems that improve the bioavailability of orally administered therapeutics, highlighting their advantages and disadvantages in generating successful anticancer oral nanomedicines.

Graphical Abstract

Rod-shaped nintedanib nanocrystals improved oral bioavailability through multiple intestinal absorption pathways

Nintedanib (BIBF) is a biopharmaceutical classification system II (BCS II) drug that has a good therapeutic effect for the treatment of nonsmall cell lung cancer; however, it shows poor oral bioavailability due to low dissolution and intestinal absorption. This study aims to fabricate rod-shaped nanocrystals to enhance oral bioavailability by improving the dissolution and absorption of BIBF in the intestine. By prescription screening, BIBF nanocrystals (BIBF-NCs) with a particle size of 325.30 ± 1.03 nm and zeta potential of 32.70 ± 1.24 mV were fabricated by an antisolvent precipitation-ultrasound approach with a stabilizer of sodium carboxyl methyl cellulose (CMC-Na). BIBF-NCs exhibited a rod-shaped morphology by transmission electron microscopy (TEM). The results of powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) showed that the crystal form of BIBF in BIBF-NCs was altered. The BIBF-NCs remarkably improved the saturation solubility and dissolution of BIBF compared with BIBF powder. According to the results of in situ single-pass intestinal perfusion (SPIP), BIBF-NCs showed improved absorption and membrane permeability, with K_a and P_app values in the jejunum of 0.21 ± 0.01 min^-1 and (4.34 ± 0.11) × 10^-4 cm/min, respectively. Further, the K_a and P_app values of BIBF-NCs were all reduced significantly after the addition of inhibitors colchicine, chlorpromazine and indomethacin, which demonstrated that BIBF-NCs could be absorbed by endocytosis mediated by caveolae and clathrin and micropinocytosis in the intestine. The cell evaluation results showed that BIBF-NCs could be taken up by macrophages and transported from Caco-2 monolayers. The in vivo pharmacokinetic results showed that the bioavailability of the BIBF-NCs was 2.51-fold higher than that of the BIBF solution (BIBF-Sol) after oral administration with a longer T_max (4.50 ± 1.00 h vs. 2.60 ± 1.92 h). In summary, rod-shaped BIBF-NCs could significantly improve oral bioavailability through multiple intestinal absorption pathways.

Bioadhesive polymer/lipid hybrid nanoparticles as oral delivery system of raloxifene with enhancive intestinal retention and bioavailability

Raloxifene (RLX) is a second-generation selective estrogen receptor modulator used to treat osteoporosis in postmenopausal women. RLX fails to be developed into injectable dosage forms due to poor solubility. Although oral formulations are clinically available, the lower bioavailability (<2%) embarrasses the pharmaceutists. This work reported a bioadhesive nanosystem intended for oral delivery of RLX to enhance its oral bioavailability and address the formulation challenge. The bioadhesive nanosystem refers to polymer-lipid hybrid nanoparticles made up of Carbopol 940, glyceryl distearate, and TGPS. RLX was solidly encapsulated into bioadhesive nanoparticles (bNPs) through a nanoprecipitation technique along with synchronous desalting of RLX·HCl. The resultant RLX-loaded bNPs (RLX-bNPs) were characterized by particle size, ζ potential, morphology, and entrapment efficiency. The in vitro release and in vivo oral bioavailability of RLX-bNPs in rats were comparatively investigated with RLX-loaded common lipid nanoparticles (RLX-cNPs). The preferred formulation possesses a particle size of 150 nm around with a polydispersity index (PDI) of 0.282. RLX-bNPs exhibited slower drug release than RLX-cNPs owing to the presence of an adhesive layer. After oral administration, RLX-bNPs resulted in significant enhancement in the bioavailability of RLX, up to 556.9% relative to RLX suspensions, while it was merely 244.7% for RLX-cNPs. Cellular testing and ex vivo transport imaging demonstrated that bNPs were endowed with excellent intestinal epithelial affinity and absorbability. Our study affords an alternative option for designing a suitable oral delivery system specific to amphiphobic drugs like RLX·HCl.

Brij-functionalized chitosan nanocarrier system enhances the intestinal permeability of P-glycoprotein substrate-like drugs

The highly expressed P-glycoprotein (Pgp) in the intestine plays a key role in preventing drugs across the intestinal epithelium, which linked by tight junctions (TJs). Thus increasing the oral bioavailability of Pgp substrate-like drugs (PSLDs) remains a great challenge. Herein, we construct a nanocarrier system derived from Brij-grafted-chitosan (BC) to enhance the oral bioavailability and therapeutic effect of berberine (BBR, a typical PLSD) against diabetic kidney disease. The developed BC nanoparticles (BC-NPs) are demonstrated to improve the intestinal permeability of BBR via transiently and reversibly modulating the intercellular TJs (paracellular pathway) and Pgp-mediated drug efflux (transcellular pathway). As compared to free BBR and chitosan nanoparticles, the BC-NPs enhanced the relative oral bioavailability of BBR in rats (4.4- and 2.7-fold, respectively), and the therapeutic potency of BBR in renal function and histopathology. In summary, such strategy may provide an effective nanocarrier system for oral delivery of BBR and PSLDs.

Effectiveness of idebenone nanorod formulations in the treatment of Alzheimer's disease

Idebenone (IDB) has demonstrated the potential to treat mitochondrial and neurodegenerative diseases, including Alzheimer's disease (AD). However, its therapeutic effects are compromised by poor compliance due to low bioavailability. The objective of this study is to fabricate IDB nanorods (IDBNRs) to improve oral bioavailability and increase concentrations in the brain in order to enhance therapeutic effects of IDB in the treatment of AD. IDBNRs showed desired sizes and rod-shaped morphologies. The release rate and the antioxidant activity of IDBNRs were improved relative to other delivery routes. The plasma and brain concentrations were enhanced due to rapid release into the systemic circulation. In behavioral tests, mice treated orally with IDBNRs showed amelioration of AD-induced impairment of learning and memory. Thus, because of improved efficiency of drug delivery, doses can be reduced, and the compliance and therapeutic experience of patients can be improved. IDBNRs may provide effective and convenient treatments for AD patients in the future.

A systematic review of functionalized polymeric nanoparticles to improve intestinal permeability of drugs and biological products

BACKGROUND

The oral route is the most frequently used and the most convenient route of drug administration, since it has several advantages, such as ease of use, patient compliance and better cost-effectiveness. However, physicochemical and biopharmaceutical limitations of various active pharmaceutical ingredients (API) hinder suitability for this route, including degradation in the gastrointestinal tract, low intestinal permeability and low bioavailability. To overcome these problems, while maintaining therapeutic efficacy, polymeric nanoparticles have attracted considerable attention for their ability to increase drug solubility, promote controlled release, and improve stability. In addition, the functionalization of nanocarriers can increase uptake and accumulation at the target site of action, and intestinal absorption, making it possible to obtain more viable, safe and efficient treatments for oral administration. <P> Objective: This systematic review aimed to seek recent advances in the literature on the use of polymeric nanoparticles functionalization to increase intestinal permeability of APIs that are intended for oral administration. <P> Method: Two bibliographic databases were consulted (PubMed and ScienceDirect). The selected publications and the writing of this systematic review were based on the guidelines mentioned in the PRISMA statement. <P> Results: Out of a total of 3036 studies, 22 studies were included in this article based on our eligibility criteria. The results were consistent for the application of nanoparticle functionalization to increase intestinal permeability. <P> Conclusion: The functionalized polymeric nanoparticles can be considered as carrier systems that improve the intestinal permeability and bioavailability of APIs, with the potential to result, in the future, in the development of oral medicines.

Nanocrystals for Improving Oral Bioavailability of Drugs: Intestinal Transport Mechanisms and Influencing Factors

With the limitation of solubility and dissolution rate of insoluble drugs, following oral administration, they would rifely prove poor and volatile bioavailability, which may fail to realize its therapeutic value. The drug nanocrystals are perceived as effective tactic for oral administration of insoluble drugs attributes to possess many prominent properties such as elevating dissolution rate and saturation solubility, high drug loading capacity, and improving oral bioavailability. Based on these advantages, the application of nanocrystals in oral drug delivery has acquired significant achievement, and so far more than 20 products of drug nanocrystals have been confirmed in the market. However, the oral absorption of drug nanocrystals is still facing huge challenges due to the limitation of many factors. Intrinsic properties of the drugs and complex physiological environment of the intestinal tract are the two most important factors affecting the oral bioavailability of drugs. In addition, the research on the multi-aspect mechanisms of nanocrystals promoting gastrointestinal absorption and bioavailability has been gradually deepened. In this review, we summarized recent advances of the nanocrystals delivered orally, and provided an overview to the research progress for crossing the intestinal tract transport mechanisms of the nanocrystals by some new research techniques. Meanwhile, the factors relevant to the transport of drug nanocrystals were also elaborated in detail. Graphical Abstract.

Preparation and in vitro evaluation of amphiphilic paclitaxel small molecule prodrugs and enhancement of oral absorption

A series of novel amphiphilic paclitaxel (PTX) small molecule prodrugs, PTX-succinic anhydride-cystamine (PTX-Cys), PTX-dithiodipropionic anhydride (PTX-SS-COOH) and PTX-succinic anhydride-cystamine-valine (PTX-SS-Val) were designed, synthesized and evaluated against cancer cell lines. Compared with paclitaxel, these prodrugs contained water-soluble groups such as amino, carboxyl and amino acid, which improved the aqueous solubility of the prodrugs. More importantly, the valine was introduced in PTX-SS-Val molecule and made the molecule conform to the structural characteristics of intestinal oligopeptide transporter PEPT1 substrate. Thus the oral bioavailability of prodrug could be improved because of the mediation of PEPT1 transporter. These small molecule paclitaxel prodrugs could self-assemble into nanoparticles in aqueous solution, which effectively improved the solubility of paclitaxel, and had certain stability in pH 6.5, pH 7.4 buffer solutions and simulated gastrointestinal fluids. Some of these prodrugs, especially for PTX-Cys and PTX-SS-Val, exhibited nearly equal or slightly better anticancer activity when compared to paclitaxel. Further studies on PTX-Cys and PTX-SS-Val showed that both had good intestinal absorption in the rat single-pass intestinal perfusion (SPIP) experiments. Oral pharmacokinetic experiments showed that PTX-SS-Val could effectively improve the oral bioavailability of PTX.

Current strategies for oral delivery of BCS IV drug nanocrystals: challenges, solutions and future trends

INTRODUCTION

Oral absorption of BCS IV drug benefits little from improved dissolution. Therefore, the absorption of BCS IV drug nanocrystals 'as a whole' strategy is preferred, and structural modification of nanocrystals is required. Surface modification helps the nanocrystals maintain particle structure before drug dissolution is needed, thus enhancing the oral absorption of BCS IV drugs and promoting therapeutic effect. Here, the main challenges and solutions of oral BCS IV drug nanocrystals delivery are discussed. Moreover, strategies for nanocrystal surface modification that facilitates oral bioavailability of BCS IV drugs are highlighted, and provide insights for the innovation in oral drug delivery.

AREAS COVERED

Promising size, shape, and surface modification of nanocrystals have gained interests for application in oral BCS IV drugs.

EXPERT OPINION

Nanocrystal surface modification is a feasible method to maintain the structural integrity of nanocrystals, and the introduced materials can also be modified to integrate additional functions to further facilitate the absorption of nanocrystals. It is expected that the absorption 'as a whole' strategy of nanocrystals will provide different choices for the oral BCS IV drugs.

Oral administration co-delivery nanoparticles of docetaxel and bevacizumab for improving intestinal absorption and enhancing anticancer activity

In this study, to improve the intestinal absorption of small molecule chemotherapeutic drug docetaxel (DTX) and macromolecular monoclonal antibody drug bevacizumab (BVZ), we designed and prepared a type of co-delivery nanoparticles for the oral administration of DTX and BVZ. Carboxymethyl chitosan (CMC) and poly(lactic-co-glycolic acid) (PLGA) were used as the carrier of DTX nanoparticles (CPNP_DTX), and methoxy polyethylene glycol-poly (β-amino ester) (mPEG-PAE) was used as the carrier of BVZ nanoparticles (PPNP_BVZ). Then, the two nanoparticles were physically mixed in mass ratios to form mixed co-delivery nanoparticles, which was named as CPNP_DTX&PPNP_BVZ. The nanoparticles were characterized with pH-sensitive drug release property. CPNP_DTX&PPNP_BVZ could significantly increase the bioavailability of DTX and BVZ according to the more cellular uptake in Caco-2 cells and the higher absorption in the intestinal tissue. Compared with free DTX and BVZ, CPNP_DTX&PPNP_BVZ showed excellent cytotoxic effects on A549 cells. Our study revealed the potential of co-delivery nanoparticles of binary mixture of chemotherapeutic small molecule and macromolecular antibody drug as an oral administration therapeutic system.

Advances in regulating physicochemical properties of mesoporous silica nanocarriers to overcome biological barriers

Mesoporous silica nanoparticles (MSNs) with remarkable structural features have been proven to be an excellent platform for the delivery of therapeutic molecules. Biological barriers in various forms (e.g., mucosal barrier, cellular barrier, gastrointestinal barrier, blood-brain barrier, and blood-tumor barrier) present substantial obstacles for MSNs. The physicochemical parameters of MSNs are known to be effective and tunable not only for load and release of therapeutic molecules but also for their biological responsiveness that is beneficial for cells and tissues. This review innovatively provides a description of how and why physicochemical properties (e.g., particle size, morphology, surface charge, hydrophilic-hydrophobic property, and surface modification) of MSNs influence their ability to cross the biological barriers prior to reaching targeted sites. First, the structural and physiological features of biological barriers are outlined. Next, the recent progresses in the critical physicochemical parameters of MSNs are highlighted from physicochemical and biological aspects. Surface modification, as an important strategy for achieving rapid transport, is also reviewed with special attention to the latest findings of bioactive groups and molecular mechanisms. Furthermore, advanced designs of multifunction intelligent MSNs to surmount the blood-tumor barrier and to actively target tumor sites are demonstrated in detail. Lastly, the biodegradability and toxicity of MSNs are evaluated. With perspectives for their potential application and biosafety, the clues in summary might lead to drug delivery with high efficiency and provide useful knowledge for rational design of nanomaterials.

Recent progress in nanoformulations of cabazitaxel

The antitumor efficacy of various paclitaxel (PTX) and docetaxel (DTX) formulations in clinical applications is seriously affected by drug resistance. Cabazitaxel, a second-generation taxane, exhibits greater anticancer activity than paclitaxel and docetaxel and has low affinity for the P-glycoprotein (P-gp) efflux pump because of its structure. Therefore, cabazitaxel has the potential to overcome taxane resistance. However, owing to the high systemic toxicity and hydrophobicity of cabazitaxel and the instability of its commercial preparation, Jevtana®, the clinical use of cabazitaxel is restricted to patients with metastatic castration-resistant prostate cancer (mCRPC) who show progression after docetaxel-based chemotherapy. Nanomedicine is expected to overcome the limitations associated with cabazitaxel application and surmount taxane resistance. This review outlines the drug delivery systems of cabazitaxel published in recent years, summarizes the challenges faced in the development of cabazitaxel nanoformulations, and proposes strategies to overcome these challenges.

Tyrosine kinase inhibitors and their unique therapeutic potentialities to combat cancer

Cancer is one of the leading causes of death with a mortality rate of 12%. Although significant progress has been achieved in cancer research, the effective treatment of cancer remains the greatest global challenge in medicine. Dysregulation of tyrosine kinases (TK) is one of the characteristics of several types of cancers. Thus, drugs that target and inhibit these enzymes, known as TK inhibitors (TKIs), are considered vital chemotherapeutics to combat various types of cancer. The oral bioavailability of available TKIs and their targeted therapy are their potential benefits. Based on these characteristics, most TKIs are included in first/second-line therapy for the treatment of different cancers. This review aims to shed light on orally-active TKIs (natural and synthetic molecules) and their promising implication in the therapy of numerous types of tumors along with their mechanisms of action. Further, recent progress in the development of synthetic and isolation of natural TKIs is reviewed. A significant growth in research regarding the development of new-generation TKIs is made with time (23 FDA-approved TKIs from 2018) due to their better therapeutic response. Oral bioavailability should be considered as an important parameter while developing of new-generation TKIs; however, drug delivery systems can also be used to address issue of poor bioavailability to a certain extent. Moreover, clinical trials should be designed in consideration of the development of resistance and tumor heterogeneity.

Galactosamine-modified PEG-PLA/TPGS micelles for the oral delivery of curcumin

In this study, galactosamine-modified poly(ethylene glycol)-poly(lactide) (Gal-PEG-PLA) polymers were synthesized and Gal-PEG-PLA/D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) micelles named as GPP micelles were designed to promote the oral absorption of a hydrophobic drug, curcumin (CUR). CUR-loaded Gal-PEG-PLA/TPGS micelles (CUR@GPP micelles) were fabricated using the thin-film dispersion method. CUR@GPP micelles had a size of about 100 nm, a near-neutral zeta potential, drug loading (DL) of 14.6%, and sustained release properties. GPP micelles with high Gal density (GPP3 micelles) were superior in facilitating uptake in epithelial cells and improving intestinal permeation. In situ intestinal absorption studies suggested that the jejunum and ileum were the best absorption segments in the intestinal tract. Additionally, biodistribution results revealed that GPP3 micelles could be remarkably taken up by the jejunum and ileum. Pharmacokinetics revealed that the maximum plasma concentration (C_max) and the area under the plasma concentration-time curve from 0 to 24 h (AUC_0-24) for CUR@GPP3 micelles were both significantly increased, and that the relative bioavailability of CUR@GPP3 micelles to CUR-loaded mPEG-PLA/TPGS micelles (CUR@PP micelles) was 258.8%. Furthermore, CUR-loaded micelles could reduce damage to the liver and intestinal tissues. This study highlights the importance of Gal content in the design of targeting nanocarrier Gal-modified micelles, which have broad prospects for oral delivery of hydrophobic drugs. Therefore, they could serve as a promising candidate for targeted delivery to the liver.

The intravenous to oral switch of taxanes: strategies and current clinical developments

The taxanes paclitaxel, docetaxel and cabazitaxel are important anticancer agents that are widely used as intravenous treatment for several solid tumor types. Switching from intravenous to oral treatment can be more convenient for patients, improve cost-effectiveness and reduce the demands of chemotherapy treatment on hospital care. However, oral treatment with taxanes is challenging because of pharmaceutical and pharmacological factors that lead to low oral bioavailability. This review summarizes the current clinical developments in oral taxane treatment. Intravenous parent drugs, strategies in the oral switch, individual agents in clinical trials, challenges and further perspectives on treatment with oral taxanes are subsequently discussed.

Toxicity Reduction and Efficacy Promotion of Doxorubicin in the Treatment of Breast Tumors Assisted by Enhanced Oral Absorption of Curcumin-Loaded Lipid-Polyester Mixed Nanoparticles

Curcumin (CUR), a polyphenol derived from turmeric, exhibits anticancer and anti-inflammatory properties. However, it has poor water solubility, stability, and oral bioavailability. To overcome these limitations, lipid-polyester mixed nanoparticles (NPs) embedded in enteric polymer-EudragitL100-55(Eu) were formulated (CUR-NPs-Eu). NPs composed of mPEG-b-PCL have a hybrid core made up of middle chain triglyceride (MCT) and poly(ε-caprolactone) (PCL) for enhancing drug loading. The CUR-NPs with MCT content of 10% had a particle size of 121.2 ± 16.8 nm, ζ potential of -16.25 ± 1.38 mV, drug loading of 9.8%, and encapsulation efficiency of 87.4%. The transport of the CUR-NPs-Eu across Caco-2 monolayers is enhanced compared with CUR alone (1.98 ± 0.94 × 10-6 of curcumin versus 55.43 ± 6.06 × 10-6 cm/s of curcumin-loaded NPs) because of the non-disassociated nanostructure during absorption. The absolute bioavailability of CUR-NPs-Eu was 7.14%, which was drastically improved from 1.08% of the CUR suspension (CUR-Sus). Therefore, in the xenograft 4T1 tumor-bearing mice, increased drug accumulation in heart and tumor was noticed because of enhanced oral bioavailability of CUR. The chemosensitizing effect of CUR was attributed to its NF-κB reduction effect (148 ± 11.83 of DOX alone versus 104 ± 8.71 of combined therapy, ng/g tissue). The cardioprotective effect of CUR was associated with maintenance of cardiac antioxidant enzyme activity and down-regulation of NF-κB. This study provided a partial illustration of the mechanisms of chemosensitizing and cardioprotective effects of CUR utilizing the oral availability promotion effect brought by the NPs-Eu formulation. And these results further demonstrated that the capability of this NPs-Eu system in oral delivery of poorly soluble and poorly permeable drugs.

Acetic acid transporter-mediated, oral, multifunctional polymer liposomes for oral delivery of docetaxel

Nanoparticle-structuring aimed at the acetic acid (A) transporter on intestinal epithelial cells and tumor cells is a new potential strategy to enhance oral bioavailability and anti-tumor efficacy. In this study, chitosan (CS) was modified with hydrophilic A and hydrophobic lipoic acid (L), to produce ACSL. A novel ACSL-modified multifunctional liposomes (Lip) loaded with docetaxel (DTX; DTX-ACSL-Lip) was then prepared and characterized. DTX-ACSL-Lip recorded higher pH sensitivity and slower release than DTX-Lip and showed dithiothreitol (DTT) response release. DTX-ACSL-Lip uptake by Caco-2 cells was also significantly enhanced mainly viaA transporters compared with DTX-Lip. ACSL modification of DTX-Lip also improved oral bioavailability by 10.70-folds, with a 3.45-fold increase in C_max and a 1.19-fold prolongation in retention time of DTX in the blood. Moreover, the grafting degree of A significantly affected cell uptake and oral bioavailability. They also showed a significant (1.33-fold) increase in drug intratumoral distribution, as well as an increase in tumor growth inhibition rate from 54.34% to 87.51% without weight loss, compared with DTX-Lip. Therefore, modification of DTX-Lip with ACSL can significantly enhance the oral bioavailability and anti-tumor efficacy of DTX without obvious toxicity, confirming the potential of the dual strategy of targeting A transporter and controlled drug release in tumor cells in oral therapy of tumor.

Panax quinquefolium saponin liposomes prepared by passive drug loading for improving intestinal absorption

Panax quinquefolium saponin (PQS) composed of 45% pseudo-ginsenoside F11 (PF11), is a natural mixture of sterol compounds obtained from the American ginseng plant, having numerous promising benefits for health. However, low solubility and permeability limit the development of PQS as a therapeutic agent for oral administration. In this study, PQS liposomes (PQS-Lips) were prepared by thin layer hydration, an in situ single-pass intestinal perfusion (SPIP) model was used to verify the improvement of membrane permeability of PQS-Lips. PQS-Lips had a high encapsulation efficiency (EE) of 65%∼70%, a particle size about 100.0 nm, and a zeta potential of -60 mV with regular spherical surface. FTIR and DSC showed the PQS in liposomes were amorphous, indicating that hydrogen bonds formed between one or several hydroxyl groups in PQS and C-O group at the phospholipid polar terminal. In addition, PQS-Lips showed sustained release in vitro than PQS at pH 1.2 and pH 6.8, and PQS-Lips had good stability in simulated gastric and intestinal fluid. Then, the absorption rate (K _a) and effective permeability coefficient (P _eff) of PQS-Lips in the whole small intestine were significantly higher than those in PQS solution (PQS-Sol), which proved that the PQS-Lips could significantly increase the membrane permeability of PQS and promote its absorption in the small intestine. From the experimental results, it could be known that liposome technology could effectively improve the absorption of PQS in the small intestine.

A surfactant-stripped cabazitaxel micelle formulation optimized with accelerated storage stability

Pluronic (Poloxomer) micelles can solubilize cabazitaxel (CTX), a second-generation taxane, and then be subjected to low-temperature "surfactant-stripping" to selectively remove loose and free surfactant, thereby increasing the drug-to-surfactant ratio. We previously found that the addition of certain other co-loaded hydrophobic cargo to the micelles can result in stabilized, surfactant-stripped cabazitaxel (sss-CTX) micelles, which resist drug aggregation in aqueous storage, a common challenge for taxanes. Here, we show that elevated temperatures can accelerate the aggregation of sss-CTX micelles, thereby enabling rapid optimization of formulations with respect to the type and ratio of co-loader used for stabilization. A sss-CTX micelle formulation was developed using mifepristone as the co-loader, at a 60% mass ratio to the CTX. Drug release, hemolysis and complement activation were investigated in vitro. Microtubule stabilization and in vitro cytotoxicity were similar for sss-CTX and a conventional Tween-80 micelle formulation. In vivo pharmacokinetics also revealed similar blood circulation of the two formulations. In subcutaneous Lewis lung carcinoma tumors, as well as in an aggressive mouse model of malignant pleural effusion, sss-CTX showed a similar therapeutic effect as the Tween-80 based formulation. Altogether, these data show that sss-CTX can achieve similar efficacy as conventional Tween-80 formulations, albeit with substantially higher drug-to-surfactant ratio and with capability of extended aqueous storage.

Microfluidic self-assembly of high cabazitaxel loading albumin nanoparticles

Cabazitaxel (CTX) is a promising anticancer drug. In this study, CTX-loaded human serum albumin (HSA) nanoparticles (MF-NPs-CTX) were prepared by a microfluidic (MF) method and were evaluated for tumor inhibition in PC-3 and HeLa cells in vitro and in vivo. The in vitro experiments showed that MF-NPs-CTX had higher drug loading content (DLC) as compared with NPs prepared by the bottom-up (BU) method (BU-NPs-CTX). Besides, MF-NPs-CTX exhibited uniform particle size distribution, high stability, sustained drug release, and high biosafety, in vivo imaging studies demonstrated that MF-NPs-CTX accumulated preferentially at the tumor site, compared to BU-NPs-CTX. The enhanced tumor uptake also increased the therapeutic efficacy of MF-NPs-CTX. Both MF-NPs-CTX and tween-CTX exhibited good tumor inhibition effect in vivo. MF-NPs-CTX had better biosafety and biocompatibility than tween-CTX. These results demonstrated that high CTX loading of MF-NPs-CTX has potential in the clinical treatment of tumors.

The Influence of Nanoparticle Properties on Oral Bioavailability of Drugs

Oral administration has been the most common therapeutic regimen in various diseases because of its high safety, convenience, lower costs, and high compliance of patients. However, susceptible in hostile gastrointestinal (GI) environment, many drugs show poor permeability across GI tract mucus and intestinal epithelium with poor oral absorption and limited therapeutic efficacy. In recent years, nanoparticulate drug delivery systems (NDDS) have become a hot research spot because of their unique advantages including protecting drug from premature degrading and interacting with the physiological environment, increasing intracellular penetration, and enhancing drug absorption. However, a slight change in physicochemistry of nanoparticles can significantly impact their interaction with biological pathways and alter the oral bioavailability of drugs. Hence, this review focuses on the factors affecting oral bioavailability from two aspects. On the one hand, the factors are the biochemical and physiological barriers in oral drugs delivery. On the other hand, the factors are the nanoparticle properties including size, surface properties, and shape of nanoparticles.

The enhancement of N-acetylcysteine on intestinal absorption and oral bioavailability of hydrophobic curcumin

To solve the low oral bioavailability of curcumin (CUR) due to the limits imposed by gastrointestinal (GI) barrier, we constructed a nano delivery system to evaluate the effect of N-acetyl-L-cysteine (NAC) on intestinal absorption and oral bioavailability of CUR. CUR was first encapsulated in bovine serum albumin nanoparticles (CUR-BSA-NPs), and then was further modified by NAC (CUR-NBSA-NPs). In situ single-pass intestinal perfusion assay demonstrated that CUR-NBSA-NPs displayed excellent permeation and absorption rates in GI tract. Additionally, the distribution study in GI tract revealed that more NBSA-NPs were absorbed by intestinal segments compared to the BSA nanoparticles. Plasma concentration-time curves in rats showed that AUC_0-t, C_max and MRT_0-t values of CUR after oral administration of CUR-NBSA-NPs were increased to 3.25-, 4.42-, and 1.43-fold compared with that of CUR suspension. In conclusion, NAC promotes oral absorption of CUR, thereby improving its oral bioavailability.