Paclitaxel-loaded PLGA microspheres with a novel morphology to facilitate drug delivery and antitumor efficiency

Development of Intratumoral Drug Delivery Based Strategies for Antitumor Therapy

Research for tumor treatment with significant therapy effects and minimal side-effects has been widely carried over the past few decades. Different drug forms have received a lot of attention. However, systemic biodistribution induces efficacy and safety issues. Intratumoral delivery of agents might overcome these problems because of its abundant tumor accumulation and retention, thereby reducing side effects. Delivering hydrogels, nanoparticles, microneedles, and microspheres drug carriers directly to tumors can realize not only targeted tumor therapy but also low side-effects. Furthermore, intratumoral administration has been integrated with treatment strategies such as chemotherapy, enhancing radiotherapy, immunotherapy, phototherapy, magnetic fluid hyperthermia, and multimodal therapy. Some of these strategies are ongoing clinical trials or applied clinically. However, many barriers hinder it from being an ideal and widely used option, such as decreased drug penetration impeded by collagen fibers of a tumor, drug squeezed out by high density and high pressure, mature intratumoral injection technique. In this review, we systematically discuss intratumoral delivery of different drug carriers and current development of intratumoral therapy strategies.

"Triple-Punch" Strategy Exosome-Mimetic Nanovesicles for Triple Negative Breast Cancer Therapy

Triple-negative breast cancer (TNBC) is the most malignant breast cancer, with high rates of relapse and metastasis. Because of the nonspecific targeting of chemotherapy and insurmountable aggressiveness, TNBC therapy lacks an effective strategy. Exosomes have been reported as an efficient drug delivery system (DDS). CD82 is a tumor metastasis inhibitory molecule that is enriched in exosomes. Aptamer AS1411 specifically targets TNBC cells due to its high expression of nucleolin. We generated a "triple-punch" cell membrane-derived exosome-mimetic nanovesicle system that integrated with CD82 overexpression, AS1411 conjugation, and doxorubicin (DOX) delivery. CD82 enrichment effectively inhibits the migration of TNBC cells. AS1411 conjugation specifically targets TNBC cells. DOX loading effectively inhibits proliferation and induces apoptosis of TNBC cells. Our results demonstrate a system of exosome-mimetic nanovesicles with "triple-punch" that may facilitate TNBC therapeutics.

Resorbable Membranes for Guided Bone Regeneration: Critical Features, Potentials, and Limitations

Lack of horizontal and vertical bone at the site of an implant can lead to significant clinical problems that need to be addressed before implant treatment can take place. Guided bone regeneration (GBR) is a commonly used surgical procedure that employs a barrier membrane to encourage the growth of new bone tissue in areas where bone has been lost due to injury or disease. It is a promising approach to achieve desired repair in bone tissue and is widely accepted and used in approximately 40% of patients with bone defects. In this Review, we provide a comprehensive examination of recent advances in resorbable membranes for GBR including natural materials such as chitosan, collagen, silk fibroin, along with synthetic materials such as polyglycolic acid (PGA), polycaprolactone (PCL), polyethylene glycol (PEG), and their copolymers. In addition, the properties of these materials including foreign body reaction, mechanical stability, antibacterial property, and growth factor delivery performance will be compared and discussed. Finally, future directions for resorbable membrane development and potential clinical applications will be highlighted.

Targeted Delivery of Anticancer Drug Loaded Charged PLGA Polymeric Nanoparticles Using Electrostatic Field

Pure positive electrostatic charges (PPECs) show suppressive effect on the proliferation and metabolism of invasive cancer cells without affecting normal tissues. PPECs are used for the delivery of drug-loaded polymeric nanoparticles (DLNs) capped with negatively charged poly(lactide-co-glycolide) (PLGA) and Poly(vinyl-alcohol) PVA into the tumor site of mouse models. The charged patch is installed on top of the skin in the mouse models' tumor region, and the controlled selective release of the drug is assayed by biochemical, radiological, and histological experiments on both tumorized models and normal rats' livers. It is found that DLNs synthesized by PLGA show great attraction to PPECs due to their stable negative charges, which would not degrade immediately in blood. The burst and drug release after less than 48h of this synthesized DLNs are 10% and 50%, respectively. These compounds can deliver the loaded-drug into the tumor site with the assistance of PPECs, and the targeted-retarded release will take place. Hence, local therapy can be achieved with much lower drug concentration (conventional chemotherapy [2 mg kg-1 ] versus DLNs-based chemotherapy [0.75 mg kg-1 ]) with negligible side effects in non-targeted organs. PPECs have many potential clinical applications for advanced-targeted chemotherapy with the lowest discernible side effects.

A γ-Glutamyl Transpeptidase (GGT)-Triggered Charge Reversal Drug-Delivery System for Cervical Cancer Treatment: In Vitro and In Vivo Investigation

Neutral/negatively charged nanoparticles are beneficial to reduce plasma protein adsorption and prolong their blood circulation time, while positively charged nanoparticles easily transverse the blood vessel endothelium into a tumor and easily penetrate the depth of the tumor via transcytosis. Γ-Glutamyl transpeptidase (GGT) is overexpressed on the external surface of endothelial cells of tumor blood vessels and metabolically active tumor cells. Nanocarriers modified by molecules containing γ-glutamyl moieties (such as glutathione, G-SH) can maintain a neutral/negative charge in the blood, as well as can be easily hydrolyzed by the GGT enzymes to expose the cationic surface at the tumor site, thus achieving good tumor accumulation via charge reversal. In this study, DSPE-PEG2000-GSH (DPG) was synthesized and used as a stabilizer to generate paclitaxel (PTX) nanosuspensions for the treatment of Hela cervical cancer (GGT-positive). The obtained drug-delivery system (PTX-DPG nanoparticles) was 164.6 ± 3.1 nm in diameter with a zeta potential of -9.85 ± 1.03 mV and a high drug-loaded content of 41.45 ± 0.7%. PTX-DPG NPs maintained their negative surface charge in a low concentration of GGT enzyme (0.05 U/mL), whereas they showed a significant charge-reversal property in the high-concentration solution of GGT enzyme (10 U/mL). After intravenous administration, PTX-DPG NPs mainly accumulated more in the tumor than in the liver, achieved good tumor-targetability, and significantly improved anti-tumor efficacy (68.48% vs. 24.07%, tumor inhibition rate, p < 0.05 in contrast to free PTX). This kind of GGT-triggered charge-reversal nanoparticle is promising to be a novel anti-tumor agent for the effective treatment of such GGT-positive cancers as cervical cancer.

Woven Vascular Stent-Grafts with Surface Modification of Silk Fibroin-Based Paclitaxel/Metformin Microspheres

In-stent restenosis caused by tumor ingrowth increases the risk of secondary surgery for patients with abdominal aortic aneurysms (AAA) because conventional vascular stent grafts suffer from mechanical fatigue, thrombosis, and endothelial hyperplasia. For that, we report a woven vascular stent-graft with robust mechanical properties, biocompatibility, and drug delivery functions to inhibit thrombosis and the growth of AAA. Paclitaxel (PTX)/metformin (MET)-loaded silk fibroin (SF) microspheres were self-assembly synthesized by emulsification-precipitation technology and layer-by-layer coated on the surface of a woven stent via electrostatic bonding. The woven vascular stent-graft before and after coating drug-loaded membranes were characterized and analyzed systematically. The results show that small-sized drug-loaded microspheres increased the specific surface area and promoted the dissolution/release of drugs. The stent-grafts with drug-loaded membranes exhibited a slow drug-release profile more for than 70 h and low water permeability at 158.33 ± 17.56 mL/cm²·min. The combination of PTX and MET inhibited the growth of human umbilical vein endothelial cells. Therefore, it was possible to generate dual-drug-loaded woven vascular stent-grafts to achieve the more effective treatment of AAA.

A novel combination for the treatment of small cell lung cancer: Active targeted irinotecan and stattic co-loaded PLGA nanoparticles

Polymeric nanoparticles are widely used drug delivery systems for cancer treatment due to their properties such as ease of passing through biological membranes, opportunity to modify drug release, specifically targeting drugs to diseased areas, and potential of reducing side effects. Here, we formulated irinotecan and Stattic co-loaded PLGA nanoparticles targeted to small cell lung cancer. Nanoparticles were successfully conjugated with CD56 antibody with a conjugation efficiency of 84.39 ± 1.01%, and characterization of formulated nanoparticles was conducted with in-vitro and in-vivo studies. Formulated particles had sizes in the range of 130-180 nm with PDI values smaller than 0.3. Encapsulation and active targeting of irinotecan and Stattic resulted in increased cytotoxicity and anti-cancer efficiency in-vitro. Furthermore, it was shown with ex-vivo biodistribution studies that conjugated nanoparticles were successfully targeted to CD56-expressing SCLC cells and distributed mainly to tumor tissue and lungs. Compliant with our hypothesis and literature, the STAT3 pathway was successfully inhibited with Stattic solution and Stattic loaded nanoparticles. Additionally, intravenous injection of conjugated co-loaded nanoparticles resulted in decreased side effects and better anti-tumor activity than individual solutions of drugs in SCLC tumor-bearing mice. These results may indicate a new treatment option for clinically aggressive small cell lung cancer.

In Vivo Degradation Studies of PGA-PLA Block Copolymer and Their Histochemical Analysis for Spinal-Fixing Application

Polylactic acid (PLA) and polyglycolic acid (PGA) are well-known medical-implant materials. Under the consideration of the limitations of degradable polymeric materials, such as weak mechanical strength and by-product release through the biodegradation process under in vivo environments, PLA–PGA block copolymer is one of the effective alternative implant materials in the clinical field. In our previous study, two types of extremely effective PGA–PLA copolymers (multi/tri-block PGA–PLA copolymers) were synthesized. These synthesized block copolymers could overcome aforementioned issues and also showed good biocompatibility. In this study, the PGA–PLA block copolymers with large molecular weight were synthesized under the same chemical scheme, and their bio durability was confirmed through the in vivo degradation behavior and histochemical analyses (by hematoxylin and eosin and immune staining) in comparison with commercial PLGA random copolymer (medical grade). Specimens for the degradation test were investigated by SEM and X-ray diffractometer (XRD). As a result, the synthesized PGA–PLA block copolymer showed good biocompatibility and had a controlled biodegrading rate, making it suitable for use in resorbable spinal-fixation materials.

Alpha-fetoprotein mediated targeting of polymeric nanoparticles to treat solid tumors

Background: Serious side effects caused by paclitaxel formulation, containing toxic solubilizer Cremophor^® EL, and its nonspecific accumulation greatly limit clinical paclitaxel application. Aim: To design paclitaxel-loaded copolymer of lactic and glycolic acids nanoparticles decorated with alpha-fetoprotein third domain (rAFP3d-NP) to increase paclitaxel safety profile. Methods: rAFP3d-NP was obtained via carbodiimide technique. Results: The particles were characterized with high paclitaxel loading content of 5% and size of 280 nm. rAFP3d-NP revealed biphasic profile with 67% release of paclitaxel during 220 h. Increased area under the curve_inf and mean residence time values after rAFP3d-NP administration confirmed prolonged blood circulation compared with paclitaxel. rAFP3d-NP demonstrated significant tumor growth inhibition at 4T1 and SKOV-3 models. Conclusion: rAFP3d-NP is a promising delivery system for paclitaxel and can be applied similarly for delivery of other hydrophobic drugs.

Delivery of Wnt inhibitor WIF1 via engineered polymeric microspheres promotes nerve regeneration after sciatic nerve crush

Injuries within the peripheral nervous system (PNS) lead to sensory and motor deficits, as well as neuropathic pain, which strongly impair the life quality of patients. Although most current PNS injury treatment approaches focus on using growth factors/small molecules to stimulate the regrowth of the injured nerves, these methods neglect another important factor that strongly hinders axon regeneration—the presence of axonal inhibitory molecules. Therefore, this work sought to explore the potential of pathway inhibition in promoting sciatic nerve regeneration. Additionally, the therapeutic window for using pathway inhibitors was uncovered so as to achieve the desired regeneration outcomes. Specifically, we explored the role of Wnt signaling inhibition on PNS regeneration by delivering Wnt inhibitors, sFRP2 and WIF1, after sciatic nerve transection and sciatic nerve crush injuries. Our results demonstrate that WIF1 promoted nerve regeneration ( p < 0.05) after sciatic nerve crush injury. More importantly, we revealed the therapeutic window for the treatment of Wnt inhibitors, which is 1 week post sciatic nerve crush when the non-canonical receptor tyrosine kinase (Ryk) is significantly upregulated.

Enhanced Doxorubicin Delivery in Folate-Overexpressed Breast Cancer Cells Using Mesoporous Carbon Nanospheres

Nanoparticle-based drug delivery reveals the safety and effectiveness and avoids premature drug release from the nanocarrier. These nanoparticles improve the bioavailability and stability of the drug against chemical and enzymatic degradation and facilitate targeted drug delivery. Herein, targeted folic acid-conjugated oxidized mesoporous carbon nanospheres (Ox-MPCNPs) were successfully fabricated and developed as antitumoral doxorubicin delivery for targeted breast cancer therapy. Fourier transform infrared spectroscopy studies confirmed that the doxorubicin was successfully bound on the Ox-MPCNP through hydrogen bonding and π-π interactions. X-ray diffraction studies showed that the synthesized doxorubicin-loaded Ox-MPCNP is semi-crystalline. The surface morphology of the synthesized doxorubicin-loaded Ox-MPCNP (DOX/Ox-MPCNP-Cys-PAsp-FA) was studied by scanning electron microscopy and high-resolution transmission electron microscopy, which demonstrates a sphere-shaped morphology. The cytotoxic effects of DOX/Ox-MPCNP-Cys-PAsp-FA were studied in MCF-7 breast cancer cells using the CytoTox96 assay kit. The study confirmed the cytotoxic effects of the synthesized nanospheres in vitro. Moreover, DOX/Ox-MPCNP-Cys-PAsp-FA-treated cells displayed efficient cell apoptosis and cell death in flow cytometry analysis. The mitochondrial fragmentation and nucleus damages were further confirmed by fluorescence microscopy. Thus, the approach used to construct the DOX/Ox-MPCNP-Cys-PAsp-FA carrier provides excellent opportunities for the targeted treatment of breast cancer.

Development and optimization of paclitaxel loaded Eudragit/PLGA nanoparticles by simplex lattice mixture design: Exploration of improved hemocompatibility and in vivo kinetics

Anemia is the most common hematological abnormality of chemotherapy, which is responsible for poor clinical outcomes. To overcome this complication, the present study was aimed for developing a Eudragit/polylactic-co-glycolic acid (PLGA) based nanoparticulate system for a model drug paclitaxel (PTX). The study was planned using a simplex lattice mixture design. PTX nanoparticles (PTXNp) were evaluated in vitro for physicochemical properties, hemolytic effects and cytotoxic effects. Further, the nanoparticles were subjected to in vivo screening using rats for hemocompatibility, pharmacokinetic profile, and biodistribution to the vital organs. The PTXNps were 65.77-214.73 nm in size, showed more than 60% sustained drug release in 360 h and caused less than 8% hemolysis. The parameters like red blood cell count, activated partial thromboplastin time (aPTT), prothrombin time (PT) and C3 complement were similar to the negative control. Cytotoxicity results suggested that all the PTXNp demonstrated drug concentration-dependent cytotoxicity. The in vivo pharmacokinetic study concluded that PTXNp formulations had significantly higher blood AUC (93.194.55-163,071.15 h*ng/mL), longer half-lives (5.80-6.35 h) and extended mean residence times (6.05-8.54 h) in comparison to PTX solution (p < 0.05). Overall, the study provides a nanoparticulate drug delivery system to deliver PTX safely and effectively along with reducing the associated hematological adverse effects.

Lung Targeted Lipopolymeric Microspheres of Dexamethasone for the Treatment of ARDS

Acute respiratory distress syndrome (ARDS), a catastrophic illness of multifactorial etiology, involves a rapid upsurge in inflammatory cytokines that leads to hypoxemic respiratory failure. Dexamethasone, a synthetic corticosteroid, mitigates the glucocorticoid-receptor-mediated inflammation and accelerates tissue homeostasis towards disease resolution. To minimize non-target organ side effects arising from frequent and chronic use of dexamethasone, we designed biodegradable, lung-targeted microspheres with sustained release profiles. Dexamethasone-loaded lipopolymeric microspheres of PLGA (Poly Lactic-co-Glycolic Acid) and DPPC (Dipalmitoylphosphatidylcholine) stabilized with vitamin E TPGS (D-α-tocopheryl polyethylene glycol succinate) were prepared by a single emulsion technique that had a mean diameter of 8.83 ± 0.32 μm and were spherical in shape as revealed from electron microscopy imaging. Pharmacokinetic and biodistribution patterns studied in the lungs, liver, and spleen of Wistar rats showed high selectivity and targeting efficiency for the lung tissue (re 13.98). As a proof-of-concept, in vivo efficacy of the microspheres was tested in the lipopolysaccharide-induced ARDS model in rats. Inflammation markers such as IL-1β, IL-6, and TNF-α, quantified in the bronchoalveolar lavage fluid indicated major improvement in rats treated with dexamethasone microspheres by intravenous route. Additionally, the microspheres substantially inhibited the protein infiltration, neutrophil accumulation and lipid peroxidation in the lungs of ARDS bearing rats, suggesting a reduction in oxidative stress. Histopathology showed decreased damage to the pulmonary tissue upon treatment with the dexamethasone-loaded microspheres. The multipronged formulation technology approach can thus serve as a potential treatment modality for reducing lung inflammation in ARDS. An improved therapeutic profile would help to reduce the dose, dosing frequency and, eventually, the toxicity.

Development of Arteannuin B Sustained-Release Microspheres for Anti-Tumor Therapy by Integrated Experimental and Molecular Modeling Approaches

Arteannuin B (AB) has been found to demonstrate obvious anti-tumor activity. However, AB is not available for clinical use due to its very low solubility and very short half-life. This study aimed to develop AB long sustained-release microspheres (ABMs) to improve the feasibility of clinical applications. Firstly, AB-polylactic-co-glycolic acid (PLGA) microspheres were prepared by a single emulsification method. In vitro characterization studies showed that ABMs had a low burst release and stable in vitro release for up to one week. The particle size of microspheres was 69.10 μm (D50). The drug loading is 37.8%, and the encapsulation rate is 85%. Moreover, molecular dynamics modeling was firstly used to simulate the preparation process of microspheres, which clearly indicated the molecular image of microspheres and provided in-depth insights for understanding several key preparation parameters. Next, in vivo pharmacokinetics (PK) study was carried out to evaluate its sustained release effect in Sprague-Dawley (SD) rats. Subsequently, the methyl thiazolyl tetrazolium (MTT) method with human lung cancer cells (A549) was used to evaluate the in vitro efficacy of ABMs, which showed the IC50 of ABMs (3.82 μM) to be lower than that of AB (16.03 μM) at day four. Finally, in vivo anti-tumor activity and basic toxicity studies were performed on BALB/c nude mice by subcutaneous injection once a week, four times in total. The relative tumor proliferation rate T/C of AMBs was lower than 40% and lasted for 21 days after administration. The organ index, organ staining, and tumor cell staining indicated the excellent safety of ABMs than Cis-platinum. In summary, the ABMs were successfully developed and evaluated with a low burst release and a stable release within a week. Molecular dynamics modeling was firstly applied to investigate the molecular mechanism of the microsphere preparation. Moreover, the ABMs possess excellent in vitro and in vivo anti-tumor activity and low toxicity, showing great potential for clinical applications.

Paclitaxel-Loaded Biotinylated Fe2+-Doped Carbon Dot: Combination Therapy in Cancer Treatment

The present research work delineates the design and preparation of covalently tailored biotinylated Fe²⁺-doped carbon dots (FCD_b). The FCD_b was successfully used as a pro-drug activator, diagnostic probe, and target-specific delivery vehicle for anticancer drug paclitaxel in pro-drug-free drug combination therapy of cancer treatment. Fe²⁺-doped carbon dot was synthesized via the hydrothermal method (FCD). The surface of FCD was covalently modified with cancer cell targeting ligand biotin (FCD_b). Microscopic and spectroscopic methods were used to characterize aqueous soluble FCD and FCD_b. Both FCD and FCD_b emit blue fluorescence under UV light irradiation. FCD and FCD_b can effectively sense H₂O₂ by fluorescence quenching as well as activate H₂O₂ (pro-drug), which oxidatively damage the DNA through the generation of reactive oxygen species (ROS: superoxide (O₂^•-), hydroxyl radical (^•OH), etc). Both FCD and FCD_b were utilized as selective cellular markers for cancer cell B16F10 owing to their high H₂O₂ content, which was more distinct in the case of FCD_b due to the overexpression of biotin receptor in cancer cell. Anticancer drug paclitaxel (PTX)-loaded FCD_b (FCD_b-PTX) was employed for the selective killing of B16F10 cancer cells. This pro-drug-free drug formulation (FCD_b-PTX) exhibited ∼2.7- to 3.5-fold higher killing of B16F10 cells mostly via early as well as late apoptotic path in comparison to noncancer NIH3T3 cells through the synergistic action of ROS (generated from H₂O₂ in the presence of FCD_b) and anticancer effect of PTX. Hence, this newly developed FCD_b-PTX can act as a potential theranostic agent in the domain of combination therapy of cancer treatment.

Combination chemotherapeutic and immune-therapeutic anticancer approach via anti-PD-L1 antibody conjugated albumin nanoparticles

Anticancer regimens have been substantially enriched through monoclonal antibodies targeting immune checkpoints, programmed cell death-1/programmed cell death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte antigen-4. Inconsistent clinical efficacy after solo immunotherapy may be compensated by nanotechnology-driven combination therapy. We loaded human serum albumin (HSA) nanoparticles with paclitaxel (PTX) via nanoparticle albumin-bound technology and pooled them with anti-PD-L1 monoclonal antibody through a pH-sensitive linker for targeting and immune response activation. Our tests demonstrated satisfactory preparation of paclitaxel-loaded, PD-L1-targeted albumin nanoparticles (PD-L1/PTX@HSA). They had small particle size (~200 nm) and polydispersity index (~0.12) and successfully incorporated each constituent. Relative to normal physiological pH, the formulation exhibited higher drug-release profiles favoring cancer cell-targeted release at low pH. Modifying nanoparticles with programmed cell death-ligand 1 increased cancer cell internalization in vitro and tumor accumulation in vivo in comparison with non-PD-L1-modified nanoparticles. PD-L1/PTX@HSA constructed by nanoparticle albumin-bound technology displayed successful tumor inhibition efficacy both in vitro and in vivo. There was successful effector T-cell infiltration, immunosuppressive programmed cell death-ligand 1, and regulatory T-cell suppression because of cytotoxic T-lymphocyte antigen-4 synergy. Moreover, PD-L1/PTX@HSA had low organ toxicity. Hence, the anti-tumor immune responses of PD-L1/PTX@HSA combined with chemotherapy and cytotoxic T-lymphocyte antigen-4 is a potential anti-tumor strategy for improving quantitative and qualitative clinical efficacy.

Multimodal imaging of drug and excipients in rat lungs following an inhaled administration of controlled-release drug laden PLGA microparticles

Controlled-release formulations, in the form of micro- or nanoparticles, are increasingly attractive to the pharmaceutical industry for drug delivery. For respiratory illnesses, controlled-release microparticle formulations provide an opportunity to deliver a higher percentage of an inhaled medicament dose to the lung, thus potentially reducing the therapeutic dose, frequency of dosing, and minimising side-effects. We describe the use of a multimodal approach consisting of MALDI MS imaging, 3D depth profiling TOF-SIMS analysis, and histopathology to monitor the distribution of drug and excipients in sections taken from excised rat lungs following an inhaled administration of drug-laden microparticles. Following a single dose, the administered drug was detected in the lung via both MALDI MS and TOF-SIMS over a range of time points. Both imaging techniques enabled the characterisation of the distribution and retention of drug particles and identified differences in the capabilities of both imaging modalities. Histochemical staining of consecutive sections was used to provide biological context to the findings and will also be discussed in this presentation. We demonstrate how this multimodal approach could be used to help increase our understanding of the use of controlled release microparticles.

Fabrication of anionic dextran-coated micelles for aptamer targeted delivery of camptothecin and survivin-shRNA to colon adenocarcinoma

In this study, we synthesized PLA-PEI micelles which was co-loaded with an anticancer drug, camptothecin (CPT), and survivin-shRNA (sur-shRNA). The hydrophobic CPT was encapsulated in the core of the polymeric micelles while sur-shRNA was adsorbed on the shell of the cationic micelles. Then, the positively-charged sur-shRNA-loaded micelles were coated with poly carboxylic acid dextran (PCAD) to form PLA/PEI-CPT-SUR-DEX. To selectively target the system to colon cancer cells, AS1411 aptamer was covalently attached to the surface of the PCAD-coated nanoparticles (PLA/PEI-CPT-SUR-DEX-APT). PLA/PEI-CPT-SUR-DEX-APT enhanced cellular uptake through receptor-mediated endocytosis followed by increased CPT accumulation, downregulation of survivin, and thereby 38% cell apoptosis. In C26 tumor-bearing mice models, after administered intravenously, PLA/PEI-CPT-SUR-DEX-APT and PLA/PEI-CPT-SUR-DEX formulations resulted in a significant inhibition of the tumor growth with tumor inhibition rate of 93% and 87%, respectively. Therefore, PLA/PEI-CPT-SUR-DEX-APT could be a versatile co-delivery vehicle for promising therapy of colorectal cancer.

Validated HPLC method for paclitaxel determination in PLGA submicron particles conjugated with α-fetoprotein third domain: Sample preparation case study

OBJECTIVES

The goal of this study was to develop sample preparation method and validate the HPLC method for precise determination of paclitaxel (Ptx) in PLGA submicron particles conjugated with protein vector molecule.

METHODS

Ptx loaded PLGA submicron particles were formulated by a single emulsification method. PLGA submicron particles were conjugated with alpha fetoprotein third domain (rAFP3d) via standard carbodiimide technique. The obtained conjugate was analyzed using 1525 binary pump and 2487 UV-VIS detector system (Waters, USA) and Reprosil ODS C-18 analytical column with the dimensions of 150mm×4.6mm ID×5μm (Dr. Maisch GmbH, Germany). Sample preparation method was developed utilizing guard cartridge with С18 stationary phase (Phenomenex, USA). HPLC method was validated according to the international conference on harmonization guidelines.

RESULTS

Efficient sample preparation was achieved using 4% of DMSO pre-dissolution, following by 10min of centrifugation at 4500g. Ptx determination was performed using acetonitrile/0.1% phosphoric acid (50:50 v/v) mobile phase at a flow rate of 1.0mL/min, injection volume of 10μL, and at 227nm. The developed method showed linearity, accuracy and precision in the range from 0.03 to 360μg/mL, with LOD and LOQ values of 0.005 and 0.03μg/mL, respectively. The intra- and inter-day precisions presented RSD values of lower than 2%.

CONCLUSION

The validated method was successfully applied to calculate Ptx encapsulation efficacy and drug loading in the developed formulation.

Intranasal delivery of Paclitaxel encapsulated nanoparticles for brain injury due to Glioblastoma

Brain injury is a common cause for physical and emotional effects to the large number of populations. Moreover, glioblastoma is the tumor in brain with no possible treatment leading to death. The blood-brain barrier's makes the treatment more difficult by preventing the drugs to reach central nervous system. Paclitaxel (PTX) encapsulated Poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), PTX-PLGA-NPs were developed using emulsification method. The PTX-PLGA-NPs were characterized using Malvern Zetasizer and Scanning Electron Microscopy and were evaluated for their cytotoxicity in U87MG cells. PTX-PLGA-NPs were prepared using single emulsion method having size of 154 ± 22.19 nm with zeta potential of -23.7 mV. The PTX-PLGA-NPs were spherical in shape and have dose dependent cytotoxicity on U87MG cells. The PTX was released from the particles with initial burst release followed by sustained release pattern. The biodistribution was studied in mice with glioblastoma model using ¹²⁵I radiolabeled PTX-PLGA-NPs and anti-glioblastoma was studied with PTX-PLGA-NPs. The biodistribution studies revealed PTX-PLGA-NPs after intranasal administration resulted in higher in vivo uptake with high anti-glioblastoma efficacy. The results suggest that PTX-PLGA-NPs administered through intranasal route have potential in the treatment of glioblastoma.

Construction and anti-tumor activities of disulfide-linked docetaxel-dihydroartemisinin nanoconjugates

Co-delivery of anti-tumor agents with outstanding stimulus-triggered drug release in tumor cells, especially with the aid of nanotechnology, provided the possibility to enhance delivery efficiency for targeting tumor cells and antitumor efficacy. In this paper, docetaxel-dihydroartemisinin nanoconjugates linked by disulfide bond were designed to increase co-delivery and anti-tumor efficacy. Docetaxel and dihydroartemisinin were synthesized using two-step reaction and furtherly assembled to nanoconjugates. Nanoprescription was optimized to evaluate its physicochemical properties. In vitro anti-tumor activities of nanoformulation were assessed by MTT. The flow cytometry was adopted to analyze cell apoptosis and cell cycle arrest. The wound healing assay was used to evaluate antimigratory-property. In vivo pharmacokinetic and pharmacodynamic studies were investigated in rats and 4T1 bearing Balb/c mice model after intravenous injection, respectively. The chemical structure of conjugate was confirmed. The prepared nanoparticles possessed uniform size distribution (172.10 ± 1.70 nm, PDI 0.05 ± 0.01), was stable during storage period, sustained release profiles and sensitive reduction responsiveness. MTT assay indicated that the toxicity of nanoconjugates was slightly weak. Flow cytometry studies showed that nanoconjugates could promote early apoptosis significantly and mainly arose from G₀/G₁ phase. The wound healing assay provided an obvious antimetastatic potential of nanoparticles in 4T1 cells. The result of pharmacokinetic study suggested that nanoconjugates exhibited higher exposure levels. In vivo pharmacodynamic research showed that mice treated with docetaxel-dihydroartemisinin nanoconjugates had lower systemic toxicity and higher survival ratio than those of control groups. This potential of nanoconjugates was developed as a novel nanoplateform to treat tumor.

A smart approach to enable preclinical studies in pharmaceutical industry: PLGA-based extended release formulation platform for subcutaneous applications

Objective: Validation of a prospective new therapeutic concept in a proof of concept study is costly and time-consuming. In particular, pharmacologically active tool compounds often lack suitable pharmacokinetic (PK) properties for subsequent studies. The current work describes a PLGA-based formulation platform, encapsulating different preclinical research compounds into extended release microparticles, to optimize their PK properties after subcutaneous administration.Significance: Developing a PLGA-based formulation platform offers the advantage of enabling early proof of concept studies in pharmaceutical research for a variety of preclinical compounds by providing a tailor-made PK profile.Methods: Different model compounds were encapsulated into PLGA microparticles, utilizing emulsification solvent evaporation or spray drying techniques. Formulations aiming different release rates were manufactured and characterized. Optimized formulations were assessed in in vivo studies to determine their PK properties, with the mean residence time (MRT) as one key PK parameter.Results: Utilizing both manufacturing methods, tested tool compounds were encapsulated successfully, with a drug load between 5% and 40% w/w, and an extended release time up to 250 h. In the following PK studies, the MRT was extended by a factor of 90, resulting in prolonged coverage of the required target through level. This approach was confirmed to be equally successful for additional internal compounds, verifying a general applicability of the platform.Conclusion: For different active pharmaceutical ingredients (API), an optimized, tailor-made PK profile was obtained utilizing the described formulation platform. This approach is applicable for a variety of pharmacologically active tool compounds, reducing timelines and costs in preclinical research.

Co-delivery of minocycline and paclitaxel from injectable hydrogel for treatment of spinal cord injury

Spinal cord injury (SCI) induces pathological and inflammatory responses that create an inhibitory environment at the site of trauma, resulting in axonal degeneration and functional disability. Combination therapies targeting multiple aspects of the injury, will likely be more effective than single therapies to facilitate tissue regeneration after SCI. In this study, we designed a dual-delivery system consisting of a neuroprotective drug, minocycline hydrochloride (MH), and a neuroregenerative drug, paclitaxel (PTX), to enhance tissue regeneration in a rat hemisection model of SCI. For this purpose, PTX-encapsulated poly (lactic-co-glycolic acid) PLGA microspheres along with MH were incorporated into the alginate hydrogel. A prolonged and sustained release of MH and PTX from the alginate hydrogel was obtained over eight weeks. The obtained hydrogels loaded with a combination of both drugs or each of them alone, along with the blank hydrogel (devoid of any drugs) were injected into the lesion site after SCI (at the acute phase). Histological assessments showed that the dual-drug treatment reduced inflammation after seven days. Moreover, a decrease in the scar tissue, as well as an increase in neuronal regeneration was observed after 28 days in rats treated with dual-drug delivery system. Over time, a fast and sustained functional improvement was achieved in animals that received dual-drug treatment compared with other experimental groups. This study provides a novel dual-drug delivery system that can be developed to test for a variety of SCI models or neurological disorders.

Polydopamine-tailored paclitaxel-loaded polymeric microspheres with adhered NIR-controllable gold nanoparticles for chemo-phototherapy of pancreatic cancer

Chemotherapeutic drugs often used as a first-line treatment of pancreatic cancer (PC) exhibit challenges due to resistance development, lack of selectivity, and tumor heterogeneity. Currently, combination chemo-photothermal therapy is known to enhance the therapeutic efficacy of chemotherapeutic drugs in PC. In this study, we develop adherent gold nanoparticles (GNPs) and paclitaxel (PTX)-loaded PLGA microspheres for the treatment of PC. Polydopamine (pD) was used as a linker to adhere GNPs to the surface of PLGA-Ms and characterized using TEM. Short-term cytotoxicity of GNPs-pD-PTX-PLGA-Ms with or without NIR treatment was evaluated using CCK-8 assays. ROS and western blot assay were performed to determine the intensity of ROS following the treatment of GNPs-pD-PTX-PLGA-Ms with or without NIR in Panc-1 cell line. Successful adhesion of GNPs on the microspheres was confirmed by TEM. CCK-8 assay revealed that GNPs-pD-PTX-PLGA-Ms with NIR showed three-fold higher cytotoxicity, compared to the group without NIR. Furthermore, ROS and western blot assay suggest that GNPs-pD-PTX-PLGA-Ms with NIR showed more ROS generation, followed by downregulation of the expression levels of antioxidant enzyme (SOD2 and CATALASE). These results suggest that the GNPs-pD-PTX-PLGA-Ms in combination with NIR irradiation can provide a synergistic chemo-photothermal therapy for the treatment of PC.

Optimization and characterization of poly(lactic-co-glycolic acid) nanoparticles loaded with astaxanthin and evaluation of anti-photodamage effect in vitro

Astaxanthin is a xanthophyll carotenoid with high beneficial biological activities, such as antioxidant function and scavenging oxygen free radicals, but its application is limited because of poor water solubility and low bioavailability. Here, we prepared and optimized poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with astaxanthin using the emulsion solvent evaporation technique and investigated the anti-photodamage effect in HaCaT cells. The four-factor three-stage Box-Behnken design was used to optimize the nanoparticle formulation. The experimental determination of the optimal nanoparticle size was 154.4 ± 0.35 nm, the zeta potential was 22.07 ± 0.93 mV, encapsulation efficiency was 96.42 ± 0.73% and drug loading capacity was 7.19 ± 0.12%. The physico-chemical properties of the optimized nanoparticles were characterized by dynamic light scattering, scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and thermo-gravimetric analyser. In vitro study exhibited the excellent cell viability and cellular uptake of optimized nanoparticles on HaCaT cells. The anti-photodamage studies (cytotoxicity assay, reactive oxygen species content and JC-1 assessment) demonstrated that the optimized nanoparticles were more effective and safer than pure astaxanthin in HaCaT cells. These results suggest that our PLGA-coated astaxanthin nanoparticles synthesis method was highly feasible and can be used in cosmetics or the treatment of skin diseases.

Enhanced cancer therapy with pH-dependent and aptamer functionalized doxorubicin loaded polymeric (poly D, L-lactic-co-glycolic acid) nanoparticles

Aptamer based drug delivery systems are gaining the importance in anticancer therapy due to their targeted drug delivery efficiency without harming the normal cells. The present work formulated the pH-dependent aptamer functionalized polymer-based drug delivery system against human lung cancer. The prepared aptamer functionalized doxorubicin (DOX) loaded poly (D, L-lactic-co-glycolic acid) (PLGA), poly (N-vinylpyrrolidone) (PVP) nanoparticles (APT-DOX-PLGA-PVP NPs) were spherical in shape with an average size of 87.168 nm. The crystallography and presence of the PLGA (poly (D, L-lactic-co-glycolic acid)) and DOX (doxorubicin) in APT-DOX-PLGA-PVP NPs were indicated by the X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and ¹H and ¹³C nuclear magnetic resonance spectrometer (NMR). The pH-dependent aptamer AS1411 based drug release triggered the cancer cell death was evidenced by cytotoxicity assay, flow cytometry, and fluorescent microscopic imaging. In addition, the cellular uptake of the DOX was determined and the apoptosis-related signaling pathway in the A549 cells was studied by Western blot analysis. Further, the in vivo study revealed that mice treated with APT-DOX-PLGA-PVP NPs were significantly recovered from cancer as evident by mice weight and tumor size followed by the histopathological study. It was reported that the APT-DOX-PLGA-PVP NPs induced the apoptosis through the activation of the apoptosis-related proteins. Hence, the present study revealed that the APT-DOX-PLGA-PVP NPs improved the therapeutic efficiency through the nucleolin receptor endocytosis targeted drug release.

Design of Astaxanthin-Loaded Core-Shell Nanoparticles Consisting of Chitosan Oligosaccharides and Poly(lactic- co-glycolic acid): Enhancement of Water Solubility, Stability, and Bioavailability

Astaxanthin, a hydrophobic carotenoid found in marine plants and animals, is claimed to exhibit various beneficial biological activities. Its use as a nutraceutical in foods, however, is currently limited by its low water-solubility and poor bioavailability. The goal of this paper was to fabricate astaxanthin-loaded colloidal particles to overcome these challenges. Astaxanthin was encapsulated in poly(lactic- co-glycolic acid) (PLGA) nanoparticles coated with chitosan oligosaccharides (COS). The properties of the loaded nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, and dynamic light scattering. The influence of PLGA properties on the loading capacity, water solubility, stability, and release of the astaxanthin were determined. The nanoparticles were smooth spheres with mean particle diameters around 150 nm and positive surface potentials (ζ = +30 mV). The encapsulation efficiency (>85%) and loading capacity (>15%) of the astaxanthin in the nanoparticles was relatively high. X-ray analysis suggested that the encapsulated astaxanthin was in an amorphous form. The nanoparticles had good dispersibility and stability in aqueous solutions, as well as high cytocompatibility. In vitro studies showed that the astaxanthin was released from the nanoparticles under simulated gastric and small intestinal conditions. Overall, our results suggest the core-shell nanoparticles developed in this study may be suitable for encapsulating this important nutraceutical in functional foods and cosmetics.

Microencapsulation of Thymol in Poly(lactide-co-glycolide) (PLGA): Physical and Antibacterial Properties

Thymol has been shown to be a safe and effective broad-spectrum antimicrobial agent that can be used as a food preservative. However, its volatile characteristics and strong odor limit its use in food products. The microencapsulation of this essential oil in biopolymers could overcome these disadvantages. In this work, thymol-loaded poly(lactide-co-glycolide) (PLGA) microparticles were successfully prepared and the optimal encapsulation efficiency was obtained at 20% (w/w) thymol. Microparticles containing thymol presented a spherical shape and smooth surface. Microencapsulation significantly improved the thermal and storage stability of thymol. In vitro release profiles demonstrated an initial fast release followed by a slow and sustained release. Thymol-loaded microparticles had strong antibacterial activity against Escherichia coli and Staphylococcus aureus, and the effectiveness of their antibacterial properties was confirmed in a milk test. Therefore, the thymol-loaded microparticles show great potential for use as an antimicrobial and as preservation additives in food.

Encapsulation of Thymol in Biodegradable Nanofiber via Coaxial Eletrospinning and Applications in Fruit Preservation

The application of the nanofiber film in the field of food preservation was an emerging research direction in recent years. With the functionalization of nanofibers, the quality and safety of food can be better guaranteed. In the present work, thymol as an antibacterial agent was encapsulated into poly(lactide- co-glycolide) to form core-shell nanofibers by coaxial electrospinning. With such a core-shell nanofiber film, thymol can be slowly released to headspace between food and the nanofiber film, inhibiting the growth of bacteria on the surface of food. The morphology and core-shell structure of nanofibers were confirmed by scanning electron microscopy and transmission electron microscopy. The antibacterial and fruit preservation abilities of the nanofiber film were tested on strawberries. Studies have shown that it can effectively inhibit the growth of bacteria, fungi, and yeast and extend the shelf life of fruit. This novel antibacterial packaging material with excellent biocompatibility, biodegradability, and good sustained release performance would have a broad application prospect in the field of food preservation.