Advances in Research on Cellulose-based Drug Carriers

Traditional drug delivery methods are prone to large fluctuations in drug concentration and require multiple frequent doses.As a green material with excellent properties,cellulose has been widely used as a drug carrier for the development and preparation of drug controlled-release system.Based on the mechanisms of slow drug release,such as dissolution-diffusion release,degradation release,and nanochannel-controlled release,the preparation methods of cellulose-based drug carriers are introduced in this paper.The applications of cellulose-based drug carriers in the fields of antitumor therapy,antibacterial therapy,chronic disease treatment,and viral disease treatment are summarized with the aim of providing a useful reference for research on cellulose-based drug carriers.

The application of open disk-like structures as model membrane and drug carriers

The objective of this review is to outline the application of bicelles(or called bilayer micelles)and bilayer nanodisks in pharmaceutics,pharmaceutical analysis and biochemistry.The application of open disk-like structures as model membrane and drug carrier has been described.The exploration of many reports in different fields suggested that these open disk-like structures have great potential in studying interactions between drug-membrane and structure/function studies of membrane-bound proteins.Furthermore,they could be applied as promising carriers for in vivo delivery of drugs,protein and peptide.

Dendritic macromolecules as nano-scale drug carriers:Phase solubility,in vitro drug release,hemolysis and cytotoxicity study

Potential of nanoscale triazine based dendritic macromolecules G1,G2 and G3 as solubility enhancers of drug was investigated.Effect of pH,concentration and generation of synthesized dendritic macromolecules on solubility of ketoprofen was studied.G3 dendrimer was further exploited as carrier for sustained release.Ketoprofen was encapsulated by inclusion complex method and also characterized by Flourier Transform Infrared spectroscopy.Sustained release study of ketoprofen from ketoprofen loaded dendrimer was carried out and compared with free ketoprofen.Hemolytic potential and Cytotoxicity assay using A-549 lung cancer cell lines revealed that synthesized triazine based dendritic macromolecules having more potential that commercially available PAMAM dendrimer.

Preparation and Characterization of Polymeric Micelles from Poly (D, L-lactide) and Methoxypolyethylene Glycol Block Copolymers as Potential Drug Carriers

Amphiphilic diblock copolymers composed of methoxy polyethylene glycol （MePEG） and poly（D,L-lactide） （PDLLA） were prepared for the preparation of polymeric micelles, The use of MePEG-PDLLA as drug carriers has been reported in the open literature, but there are only few data on the application of a series of MePEG-PDLLA copolymers with different lengths in the medical field, The shape of the polymeric micelles is also important in drug delivery, Studies on in vitro drug release profiles require a good sink condition. The critical micelle concentration of a series of MePEG-PDLLA has a significant role in drug release. To estimate their feasibility as a drug carrier, polymeric micelles made of MePEG-PDLLA block copolymer were prepared by the oil in water （O/VV） emulsion method. From dynamic light scattering （DLS） measurements, the size of the micelle formed was less than 200 nm, The critical micelle concentration of polymeric micelles with various compositions was determined using pyrene as a fluorescence probe. The critical micelle concentration decreased with increasing number of hydrophobic segments. MePEG-PDLLA micelles have a considerably low critical micelle concentration （0.4～0.5 μg/mL）, which is apparently an advantage in utilizing these micelles as drug carriers. The morphology of the polymeric micelles was observed using scanning electron microscopy （SEM） and transmission electron microscopy （TEM）, The micelles were found to be nearly spherical. The yield of the polymeric micelles obtained from the O/W method is as high as 85%.

Drug carriers based on highly protein-resistant materials for prolonged in vivo circulation time

Long-circulating drug carriers are highly desirable in drug delivery system.However,nonspecific protein adsorption leaves a great challenge in drug delivery of intravenous administration and significantly affects both the pharmacokinetic profiles of the carrier and drugs,resulting in negatively affect of therapeutic efficiency.Therefore,it is important to make surface modification of drug carriers by protein-resistant materials to prolong the blood circulation time and increase the targeted accumulation of therapeutic agents.In this review,we highlight the possible mechanism of protein resistance and recent progress of the alternative protein-resistant materials and their drug carriers,such as poly(ethylene glycol),oligo(ethylene glycol),zwitterionic materials,and red blood cells adhesion.

Nanoparticles for the treatment of spinal cord injury

Spinal cord injuries lead to significant loss of motor, sensory, and autonomic functions, presenting major challenges in neural regeneration. Achieving effective therapeutic concentrations at injury sites has been a slow process, partly due to the difficulty of delivering drugs effectively. Nanoparticles, with their targeted delivery capabilities, biocompatibility, and enhanced bioavailability over conventional drugs, are garnering attention for spinal cord injury treatment. This review explores the current mechanisms and shortcomings of existing treatments, highlighting the benefits and progress of nanoparticle-based approaches. We detail nanoparticle delivery methods for spinal cord injury, including local and intravenous injections, oral delivery, and biomaterial-assisted implantation, alongside strategies such as drug loading and surface modification. The discussion extends to how nanoparticles aid in reducing oxidative stress, dampening inflammation, fostering neural regeneration, and promoting angiogenesis. We summarize the use of various types of nanoparticles for treating spinal cord injuries, including metallic, polymeric, protein-based, inorganic non-metallic, and lipid nanoparticles. We also discuss the challenges faced, such as biosafety, effectiveness in humans, precise dosage control, standardization of production and characterization, immune responses, and targeted delivery in vivo. Additionally, we explore future directions, such as improving biosafety, standardizing manufacturing and characterization processes, and advancing human trials. Nanoparticles have shown considerable progress in targeted delivery and enhancing treatment efficacy for spinal cord injuries, presenting significant potential for clinical use and drug development.

Hydrogel-based local drug delivery strategies for spinal cord repair

Spinal cord injury results in significant loss of motor, sensory, and autonomic functions. Although a wide range of therapeutic agents have been shown to attenuate secondary injury or promote regeneration/repair in animal models of spinal cord injury, clinical translation of these strategies has been limited, in part due to difficulty in safely and effectively achieving therapeutic concentrations in the injured spinal cord tissue. Hydrogelbased drug delivery systems offer unique opportunities to locally deliver drugs to the injured spinal cord with sufficient dose and duration, while avoiding deleterious side effects associated with systemic drug administration. Such local drug delivery systems can be readily fabricated from biocompatible and biodegradable materials. In this review, hydrogel-based strategies for local drug delivery to the injured spinal cord are extensively reviewed, and recommendations are made for implementation.

Functionalized magnetic nanoparticles for drug delivery in tumor therapy

The side effects of chemotherapy are mainly the poor control of drug release. Magnetic nanoparticles(MNPs) have super-paramagnetic behaviors which are preferred for biomedical applications such as in targeted drug delivery, besides, in magnetic recording, catalysis, and others. MNPs, due to high magnetization response, can be manipulated by the external magnetic fields to penetrate directly into the tumor, thus they can act as ideal drug carriers. MNPs also play a crucial role in drug delivery system because of their high surface-to-volume ratio and porosity. The drug delivery in tumor therapy is related to the sizes, shapes, and surface coatings of MNPs as carriers. Therefore, in this review, we first summarize the effects of the sizes, shapes, and surface coatings of MNPs on drug delivery, then discuss three types of drug release systems, i.e., p H-controlled, temperature-controlled, and magnetic-controlled drug release systems, and finally compare the principle of passive drug release with that of active drug release in tumor therapy.

Advances in studies of phospholipids as carriers in skin topical application

Objective： This article provides an overview of characteristics of phospholipids, the characteristics and influential factors of liposome and microemulsion as carriers for skin delivery of drugs, and the latest advances of the phospholipids carriers in transdermal delivery systems. The perspective is that phospholipids carriers may be capable of a wide range of applications in the transdermal delivery system.

Size,shape,charge and“stealthy”surface:Carrier properties affect the drug circulation time in vivo

The present review sets out to discuss recent developments of the effects and mechanisms of carrier properties on their circulation time.For most drugs,sufficient in vivo circulation time is the basis of high bioavailability.Drug carrier plays an irreplaceable role in helping drug avoid being quickly recognized and cleared by mononuclear phagocyte system,to give drug enough time to arrive at targeted organ and tissue to play its therapeutic effect.The physical and chemical properties of drug carriers,such as size,shape,surface charge and surface modification,would affect their in vivo circulation time,metabolic behavior and biodistribution.The final circulation time of carriers is determined by the balance between macrophage recognitions,blood vessel penetration and urine excretion.Therefore,when designing the drug delivery system,we should pay much attention to the properties of drug carriers to get enough in vivo circulation time to arrive at target site eventually.This article mainly reviews the effect of carrier size,size,surface charge and surface properties on its circulation time in vivo,and discusses the mechanism of these properties affecting circulation time.This review has reference significance for the research of long-circulation drug delivery system.

Drug Release Characteristics of Hydroxyapatite Bone Cement

To discuss the feasibility of bydroxyapatite bone cement （HAC） used as a drug delivery carrier and observe the bacteriostatic activity of HAC/ Norvancomycin（ HAC/ NVCM ） composite in vitro and its release characteristics in vivo. Bacteriostatic zone and cycle of composite containing 1.5wt% of NVCM were measured in vitro studies. In vivo stndies , the composite was implanted into the top of rabbit＇ s tibia as the local medication group, HAC without NVCM being composed was also implanted and NVCM was injected into auricular vein as the systemic medication group. Cnncentrations of NVCM in blood and local bone were measured in both groups at different time points. The experimental results showed that HAC did not influence the bacteriostatic activity of NVCM otviously, and NVCM exist in the porosities of HAC in the pattern of amorphism. The blood coueemrations of NVCM in local medication group were always lower than those in systemic medication group at any time point, while the bone concentrations of NVCM in local medication group were much higher than those of systemic medication group,which remained to be 3.96μg/mg/mL after 2 weeks. And HAC has good release characteristics as a drug delivery earricr.

Novel drug delivery systems for inflammatory bowel disease

Inflammatory bowel disease(IBD)is a chronic illness characterized by relapsing inflammation of the intestines.The disorder is stratified according to the severity and is marked by its two main phenotypical representations:Ulcerative colitis and Crohn’s disease.Pathogenesis of the disease is ambiguous and is expected to have interactivity between genetic disposition,environmental factors such as bacterial agents,and dysregulated immune response.Treatment for IBD aims to reduce symptom extent and severity and halt disease progression.The mainstay drugs have been 5-aminosalicylates(5-ASAs),corticosteroids,and immunosuppressive agents.Parenteral,oral and rectal routes are the conventional methods of drug delivery,and among all,oral administration is most widely adopted.However,problems of systematic drug reactions and low specificity in delivering drugs to the inflamed sites have emerged with these regular routes of delivery.Novel drug delivery systems have been introduced to overcome several therapeutic obstacles and for localized drug delivery to target tissues.Enteric-coated microneedle pills,various nano-drug delivery techniques,prodrug systems,lipid-based vesicular systems,hybrid drug delivery systems,and biologic drug delivery systems constitute some of these novel methods.Microneedles are painless,they dislodge their content at the affected site,and their release can be prolonged.Recombinant bacteria such as genetically engineered Lactococcus Lactis and eukaryotic cells,including GM immune cells and red blood cells as nanoparticle carriers,can be plausible delivery methods when evaluating biologic systems.Nano-particle drug delivery systems consisting of various techniques are also employed as nanoparticles can penetrate through inflamed regions and adhere to the thick mucus of the diseased site.Prodrug systems such as 5-ASAs formulations or their derivatives are effective in reducing colonic damage.Liposomes can be modified with both hydrophilic and lipophilic particles and act as lipid-based vesicular systems,while hybrid drug delivery systems containing an internal nanoparticle section for loading drugs are potential routes too.Leukosomes are also considered as possible carrier systems,and results from mouse models have revealed that they control anti-and pro-inflammatory molecules.

Preparation and Drug-release Behavior of β-TCP Ceramics Drug Carrier in vitro

β-TCP ceramics drug carrier was first prepared and characterized. SEM showed that β-TCP carrier was in porous amorphous structure with diameters around 10 μm. The physical properties including apparent porosity, volume-weight, tensile strength and the permeability were measured and the results indicated those properties fit the clinical usage of β-TCP drug carrier. Furthermore, drug release experiment in vitro showed that the carrier could prolong drug release in simulated body fluid which provides basis for the clinical use of β-TCP ceramics as drug carrier.

Research progress on pharmacological action and effective drug carrier of berberine

Berberine(BBR)is an isoquinoline alkaloid that can be extracted from the traditional Chinese medicine Huang Lian.It has anti-inflammatory,anti-cancer,protection of nerves,hypoglycemic,blood lipid,anti-oxidation,antibacterial and other effects.It can be used clinically to treat chronic colitis,bacterial vaginitis,rheumatoid arthritis,breast cancer,liver cancer,Alzheimer's disease,diabetes,obesity and other common diseases.This paper reviews the pharmacological effects of berberine and the research progress of effective drug carriers in order to provide new ideas for the clinical application of berberine.

Nanomedicine Disrupts Stromal Barriers to Augment Drug Penetration for Improved Cancer Therapy

Tumor stroma composing diverse extracellular matrixes(ECM)and stromal cells shapes a condensed physical barrier,which severely hampers the efficient accessibility of nanomedicine to tumor cells,especially these deep-seated in the core of tumor.Such barrier significantly compromises the antitumor effects of drug-loaded nanomedicine,revealing the remarkable importance of disrupting stromal barrier for improved tumor therapy with deep penetration ability.To achieve this goal,various nanoparticle-based strategies have been developed,including direct depleting ECM components via delivering anti-fibrotic agents or targeting stromal cells to suppress ECM expression,dynamic regulation of nanoparticles’physicochemical properties(i.e.,size,surface charge,and morphology),mechanical force-driven deep penetration,natural/biomimetic self-driven nanomedicine,and transcytosis-inducing nanomedicine.All these nanostrategies were systemically summarized in this review,and the design principles for obtaining admirable nanomedicine were included.With the rapid development of nanotechnology,elaborate design of multifunctional nanomedicine provides new opportunities for overcoming the critical stromal barriers to maximize the therapeutic index of various therapies,such as chemotherapy,photodynamic therapy,and immunotherapy.

Mesenchymal stem cell-derived exosomes as a new drug carrier for the treatment of spinal cord injury:A review

Spinal cord injury(SCI)is a devastating traumatic disease seriously impairing the quality of life in patients.Expectations to allow the hopeless central nervous system to repair itself after injury are unfeasible.Developing new approaches to regenerate the central nervous system is still the priority.Exosomes derived from mesenchymal stem cells(MSC-Exo)have been proven to robustly quench the inflammatory response or oxidative stress and curb neuronal apoptosis and autophagy following SCI,which are the key processes to rescue damaged spinal cord neurons and restore their functions.Nonetheless,MSC-Exo in SCI received scant attention.In this review,we reviewed our previous work and other studies to summarize the roles of MSC-Exo in SCI and its underlying mechanisms.Furthermore,we also focus on the application of exosomes as drug carrier in SCI.In particular,it combs the advantages of exosomes as a drug carrier for SCI,imaging advantages,drug types,loading methods,etc.,which provides the latest progress for exosomes in the treatment of SCI,especially drug carrier.

Multi-functional Hollow Structures for Intelligent Drug Delivery

Multi-fountional hollow structures have emerged as promising platforms for intelligent drug delivery due to their unique properties,such as high loading capacities and programmed drug release.In particular,hollow multishell structures(HoMSs)with multilevel shell and space can regulate the molecular-level interaction between drugs and materials,so as to achieve the temporal-spatial order and sequential release of drugs.The anisotropic hollow structures can control the drug diffusion process by inducing the macroscopic interface flow through autonomous movement,realizing the targeted drug transport and release.In this paper,a key focus will be HoMSs with their temporal-ordered architectures and anisotropic hollow carriers with directional movement.Their synthesis mechanisms,structure-property relationships,smartly programmed drug delivery and biomedical applications will be discussed,providing insights into designing next-generation intelligent drug carriers.

Nanoparticles modified by polydopamine: Working as “drug” carriers

Inspired by the mechanism of mussel adhesion,polydopamine(PDA),a versatile polymer for surface modification has been discovered.Owing to its unique properties like extraordinary adhesiveness,excellent biocompatibility,mild synthesis requirements,as well as distinctive drug loading approach,strong photothermal conversion capacity and reactive oxygen species(ROS)scavenging facility,various PDA-modified nanoparticles have been desired as drug carriers.These nanoparticles with diverse nanostructures are exploited in multifunctions,consisting of targeting,imaging,chemical treatment(CT),photodynamic therapy(PDT),photothermal therapy(PTT),tissue regeneration ability,therefore have attracted great attentions in plenty biomedical applications.Herein,recent progress of PDA-modified nanoparticle drug carriers in cancer therapy,antibiosis,prevention of inflammation,theranostics,vaccine delivery and adjuvant,tissue repair and implant materials are reviewed,including preparation of PDA-modified nanoparticle drug carriers with various nanostructures and their drug loading strategies,basic roles of PDA surface modification,etc.The advantages of PDA modification in overcoming the existing limitations of cancer therapy,antibiosis,tissue repair and the developing trends in the future of PDA-modified nanoparticle drug carriers are also discussed.

Optimization of the Process of Gelatin-ceftiofur Sodium Microspheres

Gelatin microsphere（GMS） was prepared through W/O emulsion chemical-crossline method.The best formula was selected by examining its appearance,size,drug carrier and drug dissolution rate.The experimental results showed that the optimized gelatin microspheres were spherical ball with smooth surface and had well dispersion.The average size of blank gelatin microspheres was 15.84 μm,while the loaded microspheres＇average diameter were 33.10 μm.It was also shown that drug loading of microspheres increased with increasing loading capacity,but drug encapsulation efficiency had a trend of climbing up and then decline.The encapsulation efficiency reached the maximum when the dosage ratio was 2：1.And the results show ceftiofur sodium microspheres have sustained release in the PBS buffer of pH7.4.

Preparation and Acute Toxicology of Nano-Magnetic Ferrofluid

The nano-magnetic ferrofluid was prepared by chemical coprecipitation and its acute toxicology was investigated. The effective diameter (Eff. Diam.) of the magnetic particles was about 19.9 nm, and the concentration of the ferrofluid was 17.54 mg/ml. The acute toxic reaction and the main viscera pathological morphology of mice were evaluated after oral, intravenous and intraperitoneal administration of the nano-magnetic ferrofluid of different doses respectively. Half lethal dose (LD 50)>2104.8 mg/kg,maximum non-effect dose (ED 0)=320.10mg/kg with oral; LD 50>438.50 mg/kg, ED 0=160.05 mg/kg with intravenous route; and LD 50>1578.6 mg/kg, ED 0=320.10 mg/kg with intraperitoneal administration. Degeneration and necrosis of viscera were not found. So the nano-magnetic ferrofluid, of which toxicity is very low, may be used as a drug carrier.