Tumor-Microenvironment- Responsive Size-Shrinkable Drug-Delivery Nanosystems for Deepened Penetration Into Tumors

Carrier cascade target delivery of 5-aminolevulinic acid nanoplatform to enhance antitumor efficiency of photodynamic therapy against lung cancer

5-Aminolevulinic acid (5-ALA) is a prodrug of porphyrin IX (PpIX). Disadvantages of 5-ALA include poor stability, rapid elimination, poor bioavailability, and weak cell penetration, which greatly reduce the clinical effect of 5-ALA based photodynamic therapy (PDT). Presently, a novel targeting nanosystem was constructed using gold nanoparticles (AuNPs) as carriers loaded with a CSNIDARAC (CC9)-targeting peptide and 5-ALA via Au-sulphur and ionic bonds, respectively, and then wrapped in polylactic glycolic acid (PLGA) NPs via self-assembly to improve the antitumor effects and reduce the side effect. The successful preparation of ALA/CC9@ AuNPs-PLGA NPs was verified using ultraviolet-visible, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The analyses revealed good sphericity with a particle size of approximately140 nm, Zeta potential of 10.11 mV, and slow-controlled release characteristic in a weak acid environment. Confocal microscopy revealed targeting of NCL-H460 cells by NPs by actively internalising CC9 and avoiding the phagocytic action of RAW264.7 cells, and live fluorescence imaging revealed targeting of tumours in tumour-bearing mice. Compared to free 5-ALA, the nanosystem displayed amplified anticancer activity by increasing production of PpIX and reactive oxygen species to induce mitochondrial pathway apoptosis. Antitumor efficacy was consistently observed in three-dimensionally cultured cells as the loss of integrity of tumour balls. More potent anti-tumour efficacy was demonstrated in xenograft tumour models by decreased growth rate and increased tumour apoptosis. Histological analysis showed that this system was not toxic, with lowered liver toxicity of 5-ALA. Thus, ALA/CC9@AuNPs-PLGA NPs deliver 5-ALA via a carrier cascade, with excellent effects on tumour accumulation and PDT through passive enhanced permeability and retention action and active targeting. This innovative strategy for cancer therapy requires more clinical trials before being implemented.

Nanomaterials-Induced Redox Imbalance: Challenged and Opportunities for Nanomaterials in Cancer Therapy

Cancer cells typically display redox imbalance compared with normal cells due to increased metabolic rate, accumulated mitochondrial dysfunction, elevated cell signaling, and accelerated peroxisomal activities. This redox imbalance may regulate gene expression, alter protein stability, and modulate existing cellular programs, resulting in inefficient treatment modalities. Therapeutic strategies targeting intra- or extracellular redox states of cancer cells at varying state of progression may trigger programmed cell death if exceeded a certain threshold, enabling therapeutic selectivity and overcoming cancer resistance to radiotherapy and chemotherapy. Nanotechnology provides new opportunities for modulating redox state in cancer cells due to their excellent designability and high reactivity. Various nanomaterials are widely researched to enhance highly reactive substances (free radicals) production, disrupt the endogenous antioxidant defense systems, or both. Here, the physiological features of redox imbalance in cancer cells are described and the challenges in modulating redox state in cancer cells are illustrated. Then, nanomaterials that regulate redox imbalance are classified and elaborated upon based on their ability to target redox regulations. Finally, the future perspectives in this field are proposed. It is hoped this review provides guidance for the design of nanomaterials-based approaches involving modulating intra- or extracellular redox states for cancer therapy, especially for cancers resistant to radiotherapy or chemotherapy, etc.

Review of Advances in Coating and Functionalization of Gold Nanoparticles: From Theory to Biomedical Application

Nanoparticles, especially gold nanoparticles (Au NPs) have gained increasing interest in biomedical applications. Used for disease prevention, diagnosis and therapies, its significant advantages in therapeutic efficacy and safety have been the main target of interest. Its application in immune system prevention, stability in physiological environments and cell membranes, low toxicity and optimal bioperformances are critical to the success of engineered nanomaterials. Its unique optical properties are great attractors. Recently, several physical and chemical methods for coating these NPs have been widely used. Biomolecules such as DNA, RNA, peptides, antibodies, proteins, carbohydrates and biopolymers, among others, have been widely used in coatings of Au NPs for various biomedical applications, thus increasing their biocompatibility while maintaining their biological functions. This review mainly presents a general and representative view of the different types of coatings and Au NP functionalization using various biomolecules, strategies and functionalization mechanisms.

Nano-Drug Delivery Systems in Oral Cancer Therapy: Recent Developments and Prospective

Oral cancer (OC), characterized by malignant tumors in the mouth, is one of the most prevalent malignancies worldwide. Chemotherapy is a commonly used treatment for OC; however, it often leads to severe side effects on human bodies. In recent years, nanotechnology has emerged as a promising solution for managing OC using nanomaterials and nanoparticles (NPs). Nano-drug delivery systems (nano-DDSs) that employ various NPs as nanocarriers have been extensively developed to enhance current OC therapies by achieving controlled drug release and targeted drug delivery. Through searching and analyzing relevant research literature, it was found that certain nano-DDSs can improve the therapeutic effect of drugs by enhancing drug accumulation in tumor tissues. Furthermore, they can achieve targeted delivery and controlled release of drugs through adjustments in particle size, surface functionalization, and drug encapsulation technology of nano-DDSs. The application of nano-DDSs provides a new tool and strategy for OC therapy, offering personalized treatment options for OC patients by enhancing drug delivery, reducing toxic side effects, and improving therapeutic outcomes. However, the use of nano-DDSs in OC therapy still faces challenges such as toxicity, precise targeting, biodegradability, and satisfying drug-release kinetics. Overall, this review evaluates the potential and limitations of different nano-DDSs in OC therapy, focusing on their components, mechanisms of action, and laboratory therapeutic effects, aiming to provide insights into understanding, designing, and developing more effective and safer nano-DDSs. Future studies should focus on addressing these issues to further advance the application and development of nano-DDSs in OC therapy.

Redox-active polyphenol nanoparticles deprive endogenous glutathione of electrons for ROS generation and tumor chemodynamic therapy

Chemodynamic therapy (CDT) based on generating reactive oxygen species (ROS) is promising for cancer treatment. However, the intrinsic H2O2 is deficient for CDT, and glutathione (GSH) eliminates ROS to protect tumor cells from ROS cytotoxicity. Herein, we propose a strategy to switch the electron flow direction of GSH for O2 reduction and ROS generation rather than ROS clearance by using P(DA-Fc) nanoparticles, which are polymerized from ferrocenecarboxylic acid (Fc) coupled dopamine. P(DA-Fc) NPs with phenol-quinone conversion ability mimic NOX enzyme to deprive electrons from GSH to reduce O2 for H2O2 generation; the following •OH release can be triggered by Fc. Semiquinone radicals in P(DA-Fc) are significantly enhanced after GSH treatment, further demonstrated with strong single-electron reduction ability by calculation. In vitro and in vivo experiments indicate that P(DA-Fc) can consume intrinsic GSH to produce endogenous ROS; ROS generation strongly depends on GSH/pH level and eventually causes tumor cell death. Our work makes the first attempt to reverse the function of GSH from ROS scavenger to ROS producer, explores new roles of PDA-based nanomaterials in CDT beyond photothermal reagents and drug carriers, and provides a new strategy to improve the efficiency of CDT. STATEMENT OF SIGNIFICANCE: P(DA-Fc) nanoparticles performing tumor microenvironment response capacity and tumor reductive power utilize ability were fabricated for CDT tumor suppression. After endocytosis by tumor cells, P(DA-Fc) deprived GSH of electrons for H2O2 and •OH release, mimicking the intrinsic ROS production conducted by NADPH, further inducing tumor cell necrosis and apoptosis. Our work makes the first attempt to reverse the function of GSH from ROS scavenger to producer, explores new functions of PDA-based nanomaterials in CDT beyond photothermal reagents and drug carriers, and provides a new strategy to improve CDT efficiency.

Current perspectives and trends in nanoparticle drug delivery systems in breast cancer: bibliometric analysis and review

The treatment of breast cancer (BC) is a serious challenge due to its heterogeneous nature, multidrug resistance (MDR), and limited therapeutic options. Nanoparticle-based drug delivery systems (NDDSs) represent a promising tool for overcoming toxicity and chemotherapy drug resistance in BC treatment. No bibliometric studies have yet been published on the research landscape of NDDS-based treatment of BC. In this review, we extracted data from 1,752 articles on NDDS-based treatment of BC published between 2012 and 2022 from the Web of Science Core Collection (WOSCC) database. VOSviewer, CiteSpace, and some online platforms were used for bibliometric analysis and visualization. Publication trends were initially observed: in terms of geographical distribution, China and the United States had the most papers on this subject. The highest contributing institution was Sichuan University. In terms of authorship and co-cited authorship, the most prolific author was Yu Zhang. Furthermore, Qiang Zhang and co-workers have made tremendous achievements in the field of NDDS-based BC treatment. The article titled "Nanomedicine in cancer therapy: challenges, opportunities, and clinical applications" had the most citations. The Journal of Controlled Release was one of the most active publishers in the field. "Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries" was the most cited reference. We also analysed "hot" and cutting-edge research for NDDSs in BC treatment. There were nine topic clusters: "tumour microenvironment," "nanoparticles (drug delivery)," "breast cancer/triple-negative breast cancer," "combination therapy," "drug release (pathway)," "multidrug resistance," "recent advance," "targeted drug delivery", and "cancer nanomedicine." We also reviewed the core themes of research. In summary, this article reviewed the application of NDDSs in the treatment of BC.

Gold nanoparticles and gold nanorods in the landscape of cancer therapy

Cancer is a grievous disease whose treatment requires a more efficient, non-invasive therapy, associated with minimal side effects. Gold nanoparticles possessing greatly impressive optical properties have been a forerunner in bioengineered cancer therapy. This theranostic system has gained immense popularity and finds its application in the field of molecular detection, biological imaging, cancer cell targeting, etc. The photothermal property of nanoparticles, especially of gold nanorods, causes absorption of the light incident by the light source, and transforms it into heat, resulting in tumor cell destruction. This review describes the different optical features of gold nanoparticles and summarizes the advance research done for the application of gold nanoparticles and precisely gold nanorods for combating various cancers including breast, lung, colon, oral, prostate, and pancreatic cancer.

Sono-promoted drug penetration and extracellular matrix modulation potentiate sonodynamic therapy of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) exhibits difficult penetration of most drugs, leading to a very poor therapeutic outcome with a quite low five-year survival rate. The foremost reason is the highly-dense extracellular matrix (ECM) with abundant collagen and fibronectin secreted by the activated pancreatic stellate cells (PSCs). Here, we constructed a sono-responsive polymeric perfluorohexane (PFH) nanodroplet to elicit a deep drug penetration in PDAC via the combination of exogenous ultrasonic (US) exposure and endogenous ECM modulation for potent sonodynamic therapy (SDT) of PDAC. Under US exposure, the rapid drug release and deep penetration in PDAC tissues were realized. The released and well penetrated all-trans retinoic acid (ATRA) as an inhibitor of activated PSCs successfully reduced the secretion of ECM components to form a non-dense matrix conducive to drug diffusion. Meanwhile, the sonosensitizer, manganese porphyrin (MnPpIX), was triggered to produce robust reactive oxygen species (ROS) to exert the SDT effect under US exposure. Furthermore, oxygen (O₂) delivered by PFH nanodroplets alleviated tumor hypoxia and enhanced the eradication of cancer cells. Overall, the sono-responsive polymeric PFH nanodroplets were successfully developed as an efficient strategy for PDAC therapy. STATEMENT OF SIGNIFICANCE: Pancreatic ductal adenocarcinoma (PDAC) is a representative refractory cancer with a highly dense extracellular matrix (ECM), making it difficult for most drugs to penetrate the nearly impenetrable desmoplastic stroma. Seeking methods for deep drug penetration is an extremely pressing matter for the treatment of PDAC and many other solid tumors. Herein, we designed a fluoroalkane-modified polymer to prepare a sono-responsive polymeric perfluorohexane (PFH) nanodroplet for loading sonosensitizers, and inhibitors of activated PSCs and O₂. Under ultrasonic exposure, the nanodroplet elicited deep drug penetration in PDAC via ultrasonic disturbance and stromal remodeling, inducing potent sonodynamic therapy (SDT) of PDAC. By combining exogenous ultrasonic exposure and endogenous ECM modulation, this work successfully alleviated the severe physiological barrier of PDAC and achieved a favourable treatment effect.

Multistage O2-producing liposome for MRI-guided synergistic chemodynamic/chemotherapy to reverse cancer multidrug resistance

Reduced drug uptake and elevated drug efflux are two major mechanisms in cancer multidrug resistance (MDR). In the present study, a new multistage O₂-producing liposome with NAG/R8-dual-ligand and stimuli-responsive dePEGylation was developed to address the abovementioned issues simultaneously. The designed C-NAG-R8-PTXL/MnO₂-lip could also achieve magnetic resonance imaging (MRI)-guided synergistic chemodynamic/chemotherapy (CDT/CT). In vitro and in vivo studies showed that C-NAG-R8-PTXL/MnO₂-lip enhanced circulation time by PEG and targeted the tumor site. After tumor accumulation, endogenous l-cysteine was administered, and the PEG-attached disulfide bond was broken, resulting in the dissociation of PEG shells. The previously hidden positively charged R8 by different lengths of PEG chains was exposed and mediated efficient internalization. In addition, the oxygen (O₂) generated by C-NAG-R8-PTXL/MnO₂-lip relieved the hypoxic environment within the tumor, thus reducing the efflux of chemotherapeutic drug. O₂ was able to burst liposomes and triggered the release of PTXL. The toxic hydroxyl radical (·OH), which was produced by H₂O₂ and Mn²⁺, strengthened CDT/CT. C-NAG-R8-PTXL/MnO₂-lip was also used as MRI contrast agent, which blazed the trail to rationally design theranostic agents for tumor imaging.

Engineering biomolecular systems: Controlling the self-assembly of gelatin to form ultra-small bioactive nanomaterials

The size of nanocarriers determines the biological property of the materials, especially as it relates to intratumoral distribution. Previous research has shown that sizes of 10-50 nm penetrate deep inside the tumor, resulting in better efficacy. On the other hand, studies have shown that gelatin exhibits excellent biological properties, including compatibility, degradability, and toxicity. Therefore, FDA approved gelatin as a safe material to use as an excipient in injectables. The bottleneck is the nonexistence of smaller-sized gelatin nanoparticles (GNPs) to realize the full potential of these biomaterials. Yet, GNPs with sizes of less than 50 nm have not been reported; the synthetic strategy reported in the literature uses "uncontrolled crosslinking coupled with nanoprecipitation", resulting in larger particle size. We have developed a new method to self-assemble gelatin strands by using an anionic, phosphate-based crosslinker and controlled precipitation. The method we developed produced ultra-small gelatin nanoparticles (GX) of size 10 nm with a high degree of reproducibility, and it was characterized using dynamic light scattering (DLS), Energy-dispersive X-ray spectroscopy (EDS), High-resolution transmission, and scanning electron microscopy (HR-TEM/STEM). We also explored GX as a bioactive platform to encapsulate imaging and therapy agents within the cavity. Interestingly, we were able to encapsulate 2 nm size gold nanoparticles within the void of GX. The versatile nature of the GX particles was further demonstrated by surface functionalizing with larger size gelatin nanoparticles to form core-satellite nanocomposites. Additionally, we studied the tumor penetrability of dye-tagged 10, 50, and 200 nm gelatin nanoparticles. The study showed that smaller size gelatin nanoparticles penetrate deeper tumor regions than larger particles. In general, GX was efficient in penetrating the inner region of the spheroids. The results demonstrate the potential capabilities of ultra-small GX nanoparticles for multi-staged payload delivery, diagnostics, and cancer therapy.

Tumor microenvironment penetrating chitosan nanoparticles for elimination of cancer relapse and minimal residual disease

Chitosan and its derivatives are among biomaterials with numerous medical applications, especially in cancer. Chitosan is amenable to forming innumerable shapes such as micelles, niosomes, hydrogels, nanoparticles, and scaffolds, among others. Chitosan derivatives can also bring unprecedented potential to cross numerous biological barriers. Combined with other biomaterials, hybrid and multitasking chitosan-based systems can be realized for many applications. These include controlled drug release, targeted drug delivery, post-surgery implants (immunovaccines), theranostics, biosensing of tumor-derived circulating materials, multimodal systems, and combination therapy platforms with the potential to eliminate bulk tumors as well as lingering tumor cells to treat minimal residual disease (MRD) and recurrent cancer. We first introduce different formats, derivatives, and properties of chitosan. Next, given the barriers to therapeutic efficacy in solid tumors, we review advanced formulations of chitosan modules as efficient drug delivery systems to overcome tumor heterogeneity, multi-drug resistance, MRD, and metastasis. Finally, we discuss chitosan NPs for clinical translation and treatment of recurrent cancer and their future perspective.

Cellular Hypoxia Mitigation by Dandelion-like Nanoparticles for Synergistic Photodynamic Therapy of Oral Squamous Cell Carcinoma

Hypoxia at the tumor site limits the therapeutic effects of photodynamic therapy (PDT) in oral squamous cell carcinoma (OSCC), which is an oxygen-consumption process. Inhibiting cellular oxygen consumption and reducing cellular ATP production are expected to enhance PDT. In this study, we designed and constructed dandelion-like size-shrinkable nanoparticles for tumor-targeted delivery of hypoxia regulator resveratrol (RES) and photodynamic agent chlorine e6 (CE6). Both drugs were co-encapsulated in small-sized micelles modified with EGFR targeting ligand GE11, which was further conjugated on hyaluronic nanogel (NG) to afford RC-GMN. After targeted accumulation in tumors mediated by GE11 and enhanced penetration and retention (EPR) effects, RC-GMN was degraded by hyaluronidase (HAase) and resulted in small-sized micelles, allowing for deep penetration and dual-receptor-mediated cellular internalization. Resveratrol inhibited cellular oxygen consumption and provided sufficient oxygen for PDT, which consequently activated PDT to produce reactive oxygen species (ROS). Notably, we found that autophagy was overactivated in PDT, which was further strengthened by the hypoxia regulator resveratrol, elevating autophagic cell death. The synergistic effects of resveratrol and CE6 promoted autophagic cell death and apoptosis in the enhanced PDT, resulting in stronger antitumor effects in the orthotopic OSCC model. Therefore, the facilitated delivery of hypoxia regulator enhanced PDT efficacy by elevating oxygen content in tumor cells and inducing autophagic cell death and apoptosis, which offers an alternative strategy for enhancing the PDT effects against OSCC.

Nanodelivery Systems Delivering Hypoxia-Inducible Factor-1 Alpha Short Interfering RNA and Antisense Oligonucleotide for Cancer Treatment

Hypoxia-inducible factor (HIF), which plays a crucial role in oxygen homeostasis, contributes to immunosuppression, tumor angiogenesis, multidrug resistance, photodynamic therapy resistance, and metastasis. HIF as a therapeutic target has attracted scientists’ strong academic research interests. Short interfering RNA (siRNA) and antisense oligonucleotide (ASO) are the more promising and broadly utilized methods for oligonucleotide-based therapy. Their physicochemical characteristics such as hydrophilicity, negative charge, and high molecular weight make them impossible to cross the cell membrane. Moreover, siRNA and ASO are subjected to a rapid deterioration in circulation and cannot translocate into nuclear. Delivery of siRNA and ASO to specific gene targets should be realized without off-target gene silencing and affecting the healthy cells. Nanoparticles as vectors for delivery of siRNA and ASO possess great advantages and flourish in academic research. In this review, we summarized and analyzed regulation mechanisms of HIF under hypoxia, the significant role of HIF in promoting tumor progression, and recent academic research on nanoparticle-based delivery of HIF siRNA and ASO for cancer immunotherapy, antiangiogenesis, reversal of multidrug resistance and radioresistance, potentiating photodynamic therapy, inhibiting tumor metastasis and proliferation, and enhancing apoptosis are reviewed in this thesis. Furthermore, we hope to provide some rewarding suggestions and enlightenments for targeting HIF gene therapy.

An update on dual targeting strategy for cancer treatment

The key issue in the treatment of solid tumors is the lack of efficient strategies for the targeted delivery and accumulation of therapeutic cargoes in the tumor microenvironment (TME). Targeting approaches are designed for more efficient delivery of therapeutic agents to cancer cells while minimizing drug toxicity to normal cells and off-targeting effects, while maximizing the eradication of cancer cells. The highly complicated interrelationship between the physicochemical properties of nanoparticles, and the physiological and pathological barriers that are required to cross, dictates the need for the success of targeting strategies. Dual targeting is an approach that uses both purely biological strategies and physicochemical responsive smart delivery strategies to increase the accumulation of nanoparticles within the TME and improve targeting efficiency towards cancer cells. In both approaches, either one single ligand is used for targeting a single receptor on different cells, or two different ligands for targeting two different receptors on the same or different cells. Smart delivery strategies are able to respond to triggers that are typical of specific disease sites, such as pH, certain specific enzymes, or redox conditions. These strategies are expected to lead to more precise targeting and better accumulation of nano-therapeutics. This review describes the classification and principles of dual targeting approaches and critically reviews the efficiency of dual targeting strategies, and the rationale behind the choice of ligands. We focus on new approaches for smart drug delivery in which synthetic and/or biological moieties are attached to nanoparticles by TME-specific responsive linkers and advanced camouflaged nanoparticles.

Brain Targeting, Antioxidant Polymeric Nanoparticles for Stroke Drug Delivery and Therapy

Ischemic stroke is a leading cause of death and disability and remains without effective treatment options. Improved treatment of stroke requires efficient delivery of multimodal therapy to ischemic brain tissue with high specificity. Here, this article reports the development of multifunctional polymeric nanoparticles (NPs) for both stroke treatment and drug delivery. The NPs are synthesized using an reactive oxygen species (ROS)-reactive poly (2,2'-thiodiethylene 3,3'-thiodipropionate) (PTT) polymer and engineered for brain penetration through both thrombin-triggered shrinkability and AMD3100-mediated targeted delivery. It is found that the resulting AMD3100-conjugated, shrinkable PTT NPs, or ASPTT NPs, efficiently accumulate in the ischemic brain tissue after intravenous administration and function as antioxidant agents for effective stroke treatment. This work shows ASPTT NPs are capable of efficient encapsulation and delivery of glyburide to achieve anti-edema and antioxidant combination therapy, resulting in therapeutic benefits significantly greater than those by either the NPs or glyburide alone. Due to their high efficiency in brain penetration and excellent antioxidant bioactivity, ASPTT NPs have the potential to be utilized to deliver various therapeutic agents to the brain for effective stroke treatment.

Recent Advances in Strategies for Addressing Hypoxia in Tumor Photodynamic Therapy

Photodynamic therapy (PDT) is a treatment modality that uses light to target tumors and minimize damage to normal tissues. It offers advantages including high spatiotemporal selectivity, low side effects, and maximal preservation of tissue functions. However, the PDT efficiency is severely impeded by the hypoxic feature of tumors. Moreover, hypoxia may promote tumor metastasis and tumor resistance to multiple therapies. Therefore, addressing tumor hypoxia to improve PDT efficacy has been the focus of antitumor treatment, and research on this theme is continuously emerging. In this review, we summarize state-of-the-art advances in strategies for overcoming hypoxia in tumor PDTs, categorizing them into oxygen-independent phototherapy, oxygen-economizing PDT, and oxygen-supplementing PDT. Moreover, we highlight strategies possessing intriguing advantages such as exceedingly high PDT efficiency and high novelty, analyze the strengths and shortcomings of different methods, and envision the opportunities and challenges for future research.

Facile Fabrication of BiF3: Ln (Ln = Gd, Yb, Er)@PVP Nanoparticles for High-Efficiency Computed Tomography Imaging

X-ray computed tomography (CT) has been widely used in clinical practice, and contrast agents such as Iohexol are often used to enhance the contrast of CT imaging between normal and diseased tissue. However, such contrast agents can have some toxicity. Thus, new CT contrast agents are urgently needed. Owing to the high atomic number (Z = 83), low cost, good biological safety, and great X-ray attenuation property (5.74 cm² kg^-1 at 100 keV), bismuth has gained great interest from researchers in the field of nano-sized CT contrast agents. Here, we synthesized BiF₃: Ln@PVP nanoparticles (NPs) with an average particle size of about 380 nm. After coating them with polyvinylpyrrolidone (PVP), the BiF₃: Ln@PVP NPs possessed good stability and great biocompatibility. Meanwhile, compared with the clinical contrast agent Iohexol, BiF₃: Ln@PVP NPs showed superior in vitro CT imaging contrast. Subsequently, after in situ injection with BiF₃: Ln@PVP NPs, the CT value of the tumor site after the injection was significantly higher than that before the injection (the CT value of the pre-injection and post-injection was 48.9 HU and 194.58 HU, respectively). The morphology of the gastrointestinal (GI) tract can be clearly observed over time after oral administration of BiF₃: Ln@PVP NPs. Finally, the BiF₃: Ln@PVP NPs were completely discharged from the GI tract of mice within 48 h of oral administration with no obvious damage to the GI tract. In summary, our easily synthesized BiF₃: Ln@PVP NPs can be used as a potential clinical contrast agent and may have broad application prospects in CT imaging.

Transdermal iontophoresis delivery system for terazosin hydrochloride: an in vitro and in vivo study

This study aimed to construct a transdermal iontophoresis delivery system for terazosin hydrochloride (IDDS-TEH), which included a positive and negative electrode hydrogel prescription. Intact guinea pig skin was used as a model for the skin barrier function, and the current intensity, terazosin hydrochloride (TEH) concentration, pH, competitive salt, and transdermal enhancer properties were studied. The blood drug concentration was determined in Sprague–Dawley (SD) rats using HPLC, and the antihypertensive effects of IDDS-TEH were evaluated in spontaneously hypertensive rats (SHRs). The results showed that the steady-state penetration rate of TEH increased (from 80.36 µg·cm⁻²·h⁻¹ to 304.93 µg·cm⁻²·h⁻¹), followed by an increase in the current intensity (from 0.10 mA·cm⁻² to 0.49 mA·cm⁻²). The pH values also had a significant influence on percutaneous penetration. The blood concentration of IDDS-TEH was significantly higher (p < .05) than with passive diffusion, which could not be detected. The main pharmacokinetic parameters of the high current group (0.17 mA·cm⁻²) and the low current group (0.09 mA·cm⁻²) were AUC_0–t: 5873.0 ng·mL⁻¹·h and 2493.7 ng·mL⁻¹·h, respectively. Meanwhile, the pharmacodynamic results showed that IDDS-TEH significantly decreased the blood pressure of SHRs compared with the TEH hydrogel without loading current. Therefore, TEH could be successfully delivered by the transdermal iontophoresis system in vitro and in vivo, and further clinical studies should be explored to develop a therapeutically useful protocol.