Current Drug Delivery - Volume 18, Issue 7, 2021

Burns, mechanical injuries, skin defects, poor wound healing and scars caused by chronic diseases are serious clinical issues that affect millions of people around the world. Hyaluronic acid (HA) is one of the main components of extracellular matrix, which is widely distributed in human body. Because of its unique physical and chemical properties and diversity of physiological functions, hyaluronic acid is widely used in tissue engineering and regenerative medicine. This paper reviews the application of HA and HA based scaffolds in the regeneration and repair of skin tissue, as well as the application of HA in the fields of skin filler, wound healing, beauty, etc.

Clinically, the treatment of bone defects remains a significant challenge, as it requires autogenous bone grafts or bone graft substitutes. However, the existing biomaterials often fail to meet the clinical requirements in terms of structural support, bone induction, and controllable biodegradability. In the treatment of bone defects, 3D porous scaffolds have attracted much attention in the orthopedic field. In terms of appearance and microstructure, complex bone scaffolds created by 3D printing technology are similar to human bone. On this basis, the combination of active substances, including cells and growth factors, is more conducive to bone tissue reconstruction, which is of great significance for the personalized treatment of bone defects. With the continuous development of 3D printing technology, it has been widely used in bone defect repair as well as diagnosis and rehabilitation, creating an emerging industry with excellent market potential. Meanwhile, the diverse combination of 3D printing technology with multi-disciplinary fields, such as tissue engineering, digital medicine, and materials science, has made 3D printing products with good biocompatibility, excellent osteoinductive capacity, and stable mechanical properties. In the clinical application of the repair of bone defects, various biological materials and 3D printing methods have emerged to make patient-specific bioactive scaffolds. The microstructure of 3D printed scaffolds can meet the complex needs of bone defect repair and support the personalized treatment of patients. Some of the new materials and technologies that emerged from the 3D printing industry's advent in the past decade successfully translated into clinical practice. In this article, we first introduced the development and application of different types of materials that were used in 3D bioprinting, including metal, ceramic materials, polymer materials, composite materials, and cell tissue. The combined application of 3D bioprinting and other manufacturing methods used for bone tissue engineering are also discussed in this article. Finally, we discussed the bottleneck of 3D bioprinting technique and forecasted its research orientation and prospect.

In the past few decades, drug-eluting stents have made significant contributions to the treatment of coronary heart disease. However, due to the delayed healing of endothelial injuries caused by antiproliferative drugs and insufficient biocompatibility of vascular stent materials, late in-stent thrombosis and restenosis remain major challenges. Surface modification of cardiovascular materials to construct a biological functional layer that can regulate the behavior of blood and vascular cells is an effective way to improve the clinical performance of vascular stents. This paper reviewed the common methods of surface bio-functional modification of cardiovascular materials and especially proposed that take advantage of the new concept of precision medicine, as well as the precise and orderly regulation properties of cardiovascular disease-related gene fragments on vascular biological response behavior, the construction of gene-eluting stents which can in-situ regulate vascular intimal repair at the molecular and genetic level will become an important research direction in the future.

Mesenchymal Stem Cells (MSCs) possess unique properties that make them potential carriers for cancer therapy. MSCs have been documented to have low immunogenicity, positive safety in clinical trials, and the ability to selectively perform homing to inflammation and tumor sites. This review aims to introduce tumor tropism mechanism and effects of MSCs on tumor cells, and give an overview of MSCs in delivering gene therapeutic agents, oncolytic viruses and chemotherapeutics, as well as the application of MSCs-derived exosomes in tumor-targeted therapy.

Cardiovascular Diseases (CVD) remain the leading cause of mortality and morbidity worldwide. To date, significant progress has been made in developing stimuli-responsive nanosystems that can intrinsically interact with pathological microenvironment to achieve site-specific delivery along with on-demand drug release for precise CVD treatment. Herein, this review summarizes recent advances on smart nanosystems in response to a wide range of biological cues, including pH, enzymes, ROS, shear force, ATP, etc., which can boost drug delivery performance or monitor disease progression in a non-invasive manner. The designs, compositions and main outcomes of the single and multi-responsive nanosystems for drug delivery and/or detection purposes are provided and discussed.

Background: In the field of antibacterial, nanomaterials are favored by researchers because of their unique advantages. Medicinal plants, especially traditional Chinese medicine, are considered to be an important source of new chemicals with potential therapeutic effects, as well as an important source for the discovery of new antibiotics. MRSA is endangering people's lives as a kind of multidrug-resistant Staphylococcus aureus, which is resistant to tetracycline, amoxicillin, norfloxacin and other first-line antibiotics. It is a hotspot to find good anti-drug-resistant bacteriae, nature-originated nanomaterials with good biocompatibility. Objective: We reported the formation of phytochemical nanoparticles (NPs) by the self-assembly of berberine (BBR) and 3,4,5-methoxycinnamic acid (3,4,5-TCA) from Chinese herb medicine, which had good antibacterial activity against MRSA. Methods and Results: We found that NPs had good antibacterial activity against MRSA; especially, its antibacterial activity was better than first-line amoxicillin, norfloxacin and its self-assembling precursors on MRSA. When the concentration reached 0.1 μmol/mL, the inhibition rate of NPs reached 94.62%, which was higher than that of BBR and the other two antibiotics (p < 0.001). It was observed by Field-Emission Scanning Electron Microscopy (FESEM) that NPs could directly adhere to the bacterial surface, which might be an important aspect of the antibacterial activity of NPs. Meanwhile, we further analyzed that the self-assembly was formed by hydrogen bonds and π-π stacking through Ultraviolet-Visible (UV-vis), Fourier Transform Infrared Spectroscopy (FTIR), hydrogen Nuclear Magnetic Spectrum (1H NMR), and powder X-ray Diffraction (pXRD). NPs’ morphology was observed by FESEM and TEM. The particle size and surface charge were characterized by Dynamic Light Scattering (DLS); and the surface charge was -31.6 mv, which proved that the synthesized NPs were stable. Conclusion: We successfully constructed a naturally self-assembled nanoparticle, originating from traditional Chinese medicine, which had a good antibacterial activity for MRSA. It is a promising way to obtain natural nanoparticles from medicinal plants and apply them to antibacterial therapy.

Background: Bistorta amplexicaulis of the genus Polygonum (Polygonaceae) has been reported for its antioxidant and anticancer activities. However, the low cellular uptake of the compounds in its extract limits its therapeutic application. Objectives: The present study aimed at developing a nanoliposomal carrier system for B. amplexicaulis extracts for improved cellular uptake, thus resulting in enhanced anticancer activity. Methods: Ultra Pressure Liquid Chromatography (UPLC) was used to identify major compounds in the plant extract. Nanoliposomes (NLs) were prepared by employing a thin-film rehydration method using DPPC, PEG2000DSPE and cholesterol, followed by characterization through several parameters. In vitro screening was performed against breast cancer cell line (MCF-7) and Hepatocellular carcinoma cell line (HepG-2) using MTT-assay. Raw extract and nanoliposomes were tested on Human Umbilical Vein Endothelial Cells (HUVEC). Moreover, molecular docking was performed to validate the data obtained through wet lab. Results: The UHPLC method identified gallic acid, caffeic acid, chlorogenic acid and catechin as the major compounds in the extract. The NLs with a size ranging between 140-155 nm, zeta potential -16.9 to -19.8 mV and good polydispersity index of < 0.1 were prepared, with a high encapsulation efficiency of 81%. The MTT assay showed significantly (p > 0.05) high uptake and cytotoxicity of NLs as compared to the plant extract. Moreover, reduced toxicity against HUVEC cells was observed as compared to the extract. Also, the docking of identified compounds suggested a favorable interaction with the SH2 domain of both STAT3 and STAT5. Conclusion: Overall, the results suggest NLs as a potential platform that could be developed for the improved intracellular delivery of plant extract, thus increasing the therapeutic outcomes.

The recent increased interest in orodispersible films (ODF) stems from their ideal potential to circumvent several pharmacotherapy-related problems, such as improved medication compliance and adherence, especially in children, elderly and uncooperative patients. Their administration is well accepted by the majority of patients because ODF dissolve upon contact with the saliva in the oral cavity without the need for water intake. ODF application in personalized pharmacotherapy is currently being exploited. Moreover, innovative preparation methods and characterization technologies have been evolving in recent years, highlighting a promising future both from the technological and clinical standpoints. However, the key obstacles to the attainment of full potential of ODF in the pharmaceutical field is the lack of harmonized and well-defined quality characterization procedures, standard evaluation parameters, guidance on appropriate final product properties and specifications. This review provides an appraisal on the ODF characterization methods from slurries to the finished medicinal products with a specific focus on the technologies suitable for identification, quantification, and quality evaluation of extemporaneously prepared ODF on small batches in individualized pharmacotherapy. Generally, there is a paradigm shift from the use of the conventional quality evaluation tools and/or protocols for oral solid dosage forms to characterize ODF to more specific equipment and procedures that suit the peculiarities of the ODF.

Background: Idiopathic Pulmonary Fibrosis (IPF) is a chronic and progressive respiratory disease characterized by the destruction of the alveolar structure. In pulmonary fibrosis, aerosolized drugs are easily transferred to the systemic circulation via leakage through the injured alveolar epithelium. Therefore, pulmonary drug delivery systems for sustained distribution in fibrotic lungs are needed. Objective: We evaluated the intrapulmonary pharmacokinetics of aerosolized liposomes as pulmonary drug delivery systems in mice with bleomycin-induced pulmonary fibrosis. Methods: The aerosolized liposomal formulations and solutions of model compounds, including indocyanine green and 6-carboxyfluorescein (6-CF), were intrapulmonary administered to mice with bleomycin-induced pulmonary fibrosis. In vivo imaging for indocyanine green and 6-CF measurements in lung tissues and plasma were performed. Additionally, in vitro permeation experiments using NCI-H441 cell monolayers as a model of alveolar epithelial cells were performed. Results: The fluorescence signals of indocyanine green following the administration of liposomal formulations were observed longer in the lungs than those in solution-treated mice. Compared with the solution, the 6-CF concentrations in lung tissues after the administration of liposomal formulations were determined higher, whereas those in the plasma were lower. 6-CF permeability was significantly increased by transforming growth factor-β1 in NCI-H441 cell monolayers treated with the solution but unchanged in the presence of the liposomal formulation. Conclusion: The aerosolized liposomal formulation can prevent enhanced drug transfer from fibrotic lungs into the systemic circulation via the injured alveolar epithelium. This system may be useful for the sustained distribution of anti-fibrotic agents in fibrotic lungs and the optimization of IPF therapy.

Background: 1,4-Naphthoquinones (1,4-NQs) are secondary plant metabolites with numerous biological activities. 1,4-NQs display low water solubility and poor bioavailability. Bigels are a new technology with great potential, which are designated as drug delivery systems. Biphasic bigels consisting of solid and liquid components represent suitable formulations improving diffusion and bioavailability of NQs into the skin. Objective: We evaluated the in silico and in vitro activity of 5,8-dihydroxy-1,4-naphthoquinone (M1) and 2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone (M2) on elastase and assessed their cytotoxicity towards COLO38 melanoma cells. The 1,4-NQs were loaded into bigels for topical application. Methods: Molecular docking was performed, and cytotoxicity was evaluated on COLO38 cells using the resazurin assay. M1 and M2 were separately incorporated into bigels consisting of hydrogel organogel with sweet almond oil as the non-polar solvent and span 65 as an organogelator. Their rheological behavior and microscopic properties were characterized. The diffusion kinetics and permeation of 1,4-NQs from bigels were studied by a paddle-over-extraction cell and a “Franz cell” in vitro permeation model. Results: Molecular docking data predicted high interactions between elastase and ligands. Hydrogen bonds with LYS233 were observed for M1, M2, and phosphoramidon (positive control). The average binding energies were -8.5 and -9.7 kcal/mol for M1 and M2 and -12.6 kcal/mol for phosphoramidon. M1 and M2 inhibited the elastase activity by 58.9 and 56.6%, respectively. M1 and M2 were cytotoxic towards COLO38 cells (IC50 value: 2.6 and 9.8 μM). The M1 release from bigels was faster and more efficient than that of M2. Conclusion: M1 and M2 are promising for skin disease treatment. Biphasic organogel-hydrogel bigels are efficient and safe formulations to overcome their low bioavailability.

Aims: In this study, the dosage regimen establishment of cyadox nanosuspension against dairy cow mastitis caused by Staphylococcus aureus (S. aureus) was used as example to provide a general reference for the other novel nanocrystal preparations. Methods: The effect of cyadox against S. aureus isolates from dairy cows were firstly estimated and then the dosing regimen of nanosuspension after intramammary administration was optimized according to the model of ex vivo pharmacokinetic (PK) and pharmacodynamic (PD). The therapeutic efficacy of the predicted dosage regimen was evaluated. Results: The results demonstrated that cyadox has a concentration-dependent effect on S. aureus. The smallest and highest values of minimum inhibitory concentration (MIC) against 80 isolates was 8 and 64 μg/mL, respectively. The corresponding MIC 50 and MIC 90 was 16 and 32 μg/mL, respectively. The MIC against the pathogenic S. aureus SAHZ156001 in broth and milk were 16 and 32 μg/mL, respectively. The AUC 0-last and C max of cyadox in milk were 4442.877 μg*h/mL and 753.052 μg/mL, respectively. According to the inhibitory sigmoid E max modeling and dosage equation, the daily doses were predicted 1.6, 6.6, and 12.2 mL/gland to achieve bacteriostatic, bactericidal, and elimination effects. The dosage internal was daily administration for continuous three days. Conclusion: The clinical experiment showed that the efficient rates were 100, 100, and 90.9%, and the curative rates were 100, 81.8, and 63.6% in 12.2, 6.6 and 1.6 ml/gland groups, respectively. These results showed that cyadox nanosuspension had a good prospect as intramammary infusion to cure dairy cow mastitis infected by S. aureus. This study will be helpful for providing reference for nanocrystal preparation dosage regimen formulation.

Background: Icaritin can inhibit cell proliferation and induce apoptosis in Oral Squamous Cell Carcinoma (OSCC). However, low solubility limits its clinical usage. Objectives: To improve the efficacy of icaritin treatment, a micelle system was designed for targeted delivery of drugs to OSCC cells. Methods: In the present study, the micelles loaded with icaritin were self-assembled from the amphipathic polymer via film dispersion. Nanoparticles were characterized with the transmission electron microscope and dynamic light scattering. The cytotoxicity of icaritin nanoparticles was analyzed by CCK-8, and in vitro target-selective intracellular uptake behaviors were observed using a laser confocal microscope. Results: The micelles were spherical with the mean diameter of 121.2 nm. in vitro studies revealed that icaritin was stablely and slowly released from micelles. Cytotoxicity analysis demonstrated that icartin-loaded micelles exhibited better therapeutic efficacy compared with free icaritin. Cellular uptake and intracellular release results revealed that micelles efficiently delivered icaritin into OSCC cells. Conclusion: These results suggest that encapsulated icaritin in polycaprolactone - polyethylene glycol (PCL-PEG) micelles may provide safe and effective drug delivery in OSCC treatments.

Introduction: Quercetin is the main active ingredient of Xanthoceras sorbifolia Bunge. Traditional compatibility theory of traditional Chinese medicine has typically reported a synergistic interaction among multiple components, while the synergistic effects of nanoemulsion have not been fully clarified. Objective: The paper aims to study the preparation and characterization of quercetin-based Mongolia Medicine Sendeng-4 nanoemulsion (N-QUE-NE) and its antibacterial activity and mechanisms. Methods: The morphology of the nanoemulsion was observed by Transmission Electron Microscopy (TEM), and the zeta potential, Polydispersity Index (PDI), and particle size distribution were determined by the nanometer particle size analyze. The stability of nanoemulsion was investigated by light test, high-speed centrifugal test and storage experiment at different temperatures. The combined bacteriostatic effect of N-QUE-NE was studied in vitro by the double-dilution method and checkerboard dilution method. Results: The appearance of N-QUE-NE was pale yellow, clear and transparent. The nanoemulsion particles were spherical and uniformly distributed under TEM. The PDI was 0.052, the average particle size was 19.6nm, and the Zeta potential was -0.2mV. When quercetin nanoemulsion (QUENE) was used in combination with tannin nanoemulsion (TAN-NE) and toosendanin nanoemulsion (TOO-NE), it exhibited a synergistic antibacterial effect. However, the combination of QUE-NE and geniposide nanoemulsion (GEN-NE) exhibited an antagonistic effect. It was revealed that the antibacterial effect was in the order of quercetin-tannin-toosendanin nanoemulsion (QUE-TANTOO- NE) > quercetin-tannin nanoemulsion (QUE-TAN-NE) > QUE-NE > quercetin-tannintoosendanin- geniposide nanoemulsion (QUE-TAN-TOO-GEN-NE). Conclusion: This study explored the preparation and efficacy of N-QUE-NE, and the results showed that quercetin, tannin and toosendanin had satisfactory synergistic antibacterial effects. The antagonistic effect of quercetin and geniposide in nanoemulsion indicated that it is not beneficial to the antibacterial effect of Sendeng-4, and further research needs to be conducted to clarify its antibacterial effect.

Aim: This study aimed to investigate the influence of the preparation process and composition on the microstructure of the O/W primary emulsions and the corresponding impact on the formation of oil-in-water-in-oil (O/W/O) multiple emulsions. Objectives: Multiple emulsions were prepared by a two-step emulsification method and the microstructure was characterized by the microscope. Methods: The primary emulsion was prepared by four kinds of preparation methods, which include both high-energy and low-energy emulsification, and then the primary emulsion was re-emulsified by stirring in the outer phase. Result: Through the theoretical investigation and the corresponding verification experiments of the interfacial film, the geometric reason for O/W/O multiple emulsion which was relatively difficult to prepare has been found. The microstructure of O/W particles was more obvious, and the particle size became smaller with the increase of the hydrophilic emulsifier amount beneficial to the formation and stability of O/W/O structures. However, the excess emulsifier that existed in the water phase could interfere the stability of the W/O interface. Moreover, the viscosity of inner oil phase had a large influence on the formation of O/W/O emulsion by affecting the particle size of the primary emulsion and the dynamic equilibrium between the inner and outer oil phase. Conclusion: It can be concluded that fine multiple emulsions were formed when the particle size of the primary emulsion was moderate since the large particles would break through the outer interface membrane and small particles would combine with the outer oil phase due to the Ostwald ripening.

Background: Chronic inflammation and lack of angiogenesis are the important pathological mechanisms in Deep Tissue Injury (DTI). Curcumin is a well-known anti-inflammatory and antioxidant agent. However, curcumin is unstable under acidic and alkaline conditions and can be rapidly metabolized and excreted in the bile, which shortens its bioactivity and efficacy. Objective: This study aimed to prepare curcumin-loaded poly (lactic-co-glycolic acid) nanoparticles (CPNPs) and to elucidate the protective effects and underlying mechanisms of wound healing in DTI models. Methods: CPNPs were evaluated for particle size, biocompatibility, in vitro drug release and their effect on in vivo wound healing. Results: The results of in vivo wound closure analysis revealed that CPNP treatments significantly improved wound contraction rates (p<0.01) at a faster rate than the other three treatment groups. H staining revealed that CPNP treatments resulted in complete epithelialization and thick granulation tissue formation. In contrast, control groups resulted in a lack of compact epithelialization and persistence of inflammatory cells within the wound sites. Quantitative real-time PCR analysis showed that treatment with CPNPs suppressed IL-6 and TNF-α mRNA expression, and up-regulated TGF-β, VEGF-A and IL-10 mRNA expression. Western blot analysis showed up-regulated protein expression of TGF-β, VEGF-A and phosphorylated-STAT3. Conclusion: Our results showed that CPNPs enhanced wound healing in DTI models through modulation of the JAK2/STAT3 signalling pathway and subsequent upregulation of pro-healing factors.

Background: There have been massive efforts on vaccine development against HIV-1 since its discovery. Various approaches have been taken to attention, including rational vaccine design, optimized delivery systems and heterologous regimen to eradicate the virus. DNA vaccines fundamentally induce host immune responses by genetically engineered plasmids encoding antigens and expressed in vivo without the need of the specific delivery system. Therefore, long-term endogenous antigen expression could be possible. Objective: In this study, we aimed at evaluation and comparison of DNA and protein vaccine based on two forms of full and truncated HIV-1 p24-nef antigens by in silico design in BLALB/c. Methods: The recombinant pcDNA3.1 harboring two sets of HIV-1 p24 and nef genes in truncated and full forms were generated and applied to immunize BALB/c along with the corresponding proteins via three different DNA/DNA, DNA/protein and protein/protein regimens. Results: The results showed that the applied regimens could elicit strong immune responses in comparison with controls and the prim-boost DNA/protein regimen reached the highest immune induction (p < 0.05). Moreover, prime-boost approach was assessed more successfully in a qualitatively broad Th1 response induction. The truncated form of the antigens, p24(80-231 aa)-AAY- Nef (120-150), was evaluated more immunogenic in agreement with the in silico investigation. Conclusion: The truncated form of p24-Nef was evaluated highly immunogenic specially when applied in prim-boost DNA/Protein regimen and could be investigated in other delivery systems and a proper animal model to achieve a therapeutic vaccine candidate against HIV-1.

Introduction: The most common treatment for Primary Open-Angle Glaucoma (POAG) is the daily use of eye drops. Sustained-release drug delivery systems have been developed to improve patient adherence by achieving prolonged therapeutic drug concentrations in ocular target tissues while limiting systemic exposure. The purpose of this study is to compare the efficacy and safety of bimatoprost inserts with bimatoprost eye drops in patients with POAG and Ocular Hypertension (OH). Methods: We include OH and POAG patients aged between 40 and 75 years-old. Both OH and POAG patients had intraocular pressure (IOP) greater than 21 and ≤30 mmHg at 9:00 am without glaucoma medication and normal biomicroscopy. Five normal patients with IOP≤14 mmHg constitute the control group. A chitosan-based insert of bimatoprost was placed at the upper conjunctival fornix of the right eye. In the left eye, patients used one drop of LumiganTM daily at 10:00 pm. For statistical analysis, a two-way analysis of variance (ANOVA), Student t-test, and paired t-test is used. Results: Sixteen POAG and 13 OH patients with a mean age of 61 years were assessed. In both eyes, IOP reduction was similar during three weeks of follow-up (19.5±2.2 mmHg and 16.9±3.1 mmHg), insert, and eye drop, respectively; P=0.165). The percentage of IOP reduction in the third week was 30% for insert and 35% for eye drops (P=0.165). No intolerance or discomfort with the insert was reported. Among the research participants, 58% preferred the use of the insert while 25% preferred eye drops, and 17% reported no preference. Conclusion: Bimatoprost-loaded inserts showed similar efficacy to daily bimatoprost eye drops during three weeks of follow up, without major side effects. This might suggest a possible change in the daily therapeutic regimen for the treatment of POAG and OH.