A comparable study of polyglycolic acid's degradation on macrophages' activation.

Polyglycolic acid (PGA) is a faster biodegradable polymer for various implants, frequently causing different macrophages' activation. In this study, we undertook a comparable study of PGA's degradation on macrophages' activation with different PGA crystallinity (in porous and fibrous 3D scaffolding format) in an in vitro and in vivo model. The incubation medium containing PGA degradation products, with different pH value of 7.1, 6.1 and 3.6, was added to RAW 264.7 macrophages' culture to simulate different degradation phases. The addition of hydrochloric acid with the same pH values in the culture media was used to compare and simplify the acid types' effect on macrophages. The scaffolds were implanted to mouse subcutaneously for 6 weeks. To correlate the degradation rate between the in vitro and in vivo models, PGA scaffolds were grafted by rhodamine-b covalently enabling the detection of PGA degradation through fluorescence intensity decay. It was confirmed that porous PGA degraded faster than fibrous scaffolds due to lower crystallinity. The acidic PGA degradation products (GA) did not promote IL-10 production, but inhibited IL-1ß, IL-6 and TNF-α production in 7-days' culture significantly. The use of HCl with the same pH value as PGA degradation products in culture did not produce the same inhibition effect as GA. The mouse model showed that the degradation of PGA scaffolds was accelerated in vivo in the first two weeks, mainly due to tissue ingrowth. The fast degradation of porous scaffolds triggered M1 macrophages into the implantation site, whilst the slow degradation of PGA fibers promoted the polarization of macrophages into M2 pro-healing phenotypes. This study provides a good foundation to study and design biodegradable biomaterials toward immunomodulation.

Hybrid nanovaccine for the co-delivery of the mRNA antigen and adjuvant.

For efficient cancer vaccines, the antitumor function largely relies on cytotoxic T cells, whose activation can be effectively induced via antigen-encoding mRNA, making mRNA-based cancer vaccines an attractive approach for personalized cancer therapy. While the liposome-based delivery system enables the systemic delivery and transfection of mRNA, incorporating an adjuvant that is non-lipid like remains challenging, although the co-delivery of mRNA (antigen) and effective adjuvant is key to the activation of the cytotoxic T cells. This is because the presence of an adjuvant is important for dendritic cell maturation-another necessity for cytotoxic T cell activation. In the present work, we designed a poly (lactic-co-glycolic acid) (PLGA)-core/lipid-shell hybrid nanoparticle carrier for the co-delivery of mRNA and gardiquimod (adjuvant that cannot be incorporated into the lipid shell). We demonstrated in the present work that the co-delivery of mRNA and gardiquimod led to the effective antigen expression and DC maturation in vitro. The intravenous administration of the hybrid nanovaccine resulted in the enrichment of mRNA expression in the spleen and a strong immune response in vivo. The simultaneous delivery of the antigen and adjuvant both spatially and temporally via the core/shell nanoparticle carrier is found to be beneficial for tumor growth inhibition.

A core-shell structure QRu-PLGA-RES-DS NP nanocomposite with photothermal response-induced M2 macrophage polarization for rheumatoid arthritis therapy.

Rheumatoid arthritis (RA) is a degenerative joint disease caused by autoimmunity; for the effective treatment of RA while avoiding the side effects of conventional drugs, we have proposed a new therapeutic strategy to eliminate the inflammatory response in RA by regulating the immune system that promotes the transformation of M1-type macrophages to M2-type macrophages. Herein, we designed and synthesized a core-shell nanocomposite (QRu-PLGA-RES-DS NPs), which showed an effective therapeutic effect on RA by accurately inducing the polarization of M2 macrophages. In this system, the quadrilateral ruthenium nanoparticles (QRuNPs) with a photothermal effect were utilized as a core and the thermosensitive molecular poly (lactic-co-glycolic acid) (PLGA) modified with the targeted molecule dextran sulfate (DS) was employed as a shell. Then, the nanocarrier QRu-PLGA-DS NPs effectively improved the water solubility and targeting of resveratrol (RES) through self-assembly. Therefore, the QRu-PLGA-RES-DS NPs significantly enhanced the ability of RES to reverse the M1 type macrophages to the M2 type macrophages through an accurate release. In vivo experiments further demonstrated that the QRu-PLGA-RES-DS NPs could effectively accumulate in the lesion area with an exogenous stimulus, and this significantly enhanced the transformation of the M2 type macrophages and decreased the recruitment of the M1 type macrophages. Furthermore, the QRu-PLGA-RES-DS NPs effectively treated RA by eliminating the inflammatory response; in addition, photoacoustic imaging (PA) of the QRu NPs provided image guidance for the distribution and analysis of nanomedicine in inflammatory tissues. Hence, this therapeutic strategy promotes the biological applications of Ru-based nanoparticles in disease treatment.

Core-shell microencapsulation of curcumin in PLGA microparticles: programmed for application in ovarian cancer therapy.

In our study, we have established a novel liquid-driven co-flow focusing (LDCF) process to fabricate curcumin (CUR)-loaded poly (lactic-co-glycolic acid) (PLGA) microparticles (CPMs). LDCF-CPMs of size 20.26 ± 2.37 µm have high encapsulation efficiency (>70%) and were intended for application in ovarian cancer by intraperitoneal (IP) administration. LDCF-CPMs have smooth surface with narrow size distribution and a core-shell structured verified by confocal microscopy which can be precisely controlled by changing the flow rates of focusing, outer and inner phases. The LDCF-CPMs reveal the physiochemical stability with sustained release profile corresponding to 95% CUR release over a period of 14 days in an in vitro release medium. Moreover, LDCF-CPMs were testified for cytotoxicity against SKOV-3 ovarian cancer cell lines and peritoneal delivery advantages by animal experiments. The pharmacokinetics of LDCF-CPMs in rats following IP injection shows slow systemic absorption with mean residence time (MRT) of 13.54 h in comparison with 9.82 and 6.74 h for SE-CPMs and free CUR, respectively. In addition, IP delivery of CUR can expose the ovarian tumour to higher concentration for a longer duration by programming the thickness of the shell. The study provides compelling evidence for LDCF-CPMs having high therapeutic opportunity in the treatment of peritoneal cancers, such as ovarian, that reside in the peritoneal cavity.

Fab-conjugated PLGA nanoparticles effectively target cancer cells expressing human CD44v6.

Targeting of CD44 isoforms containing exon v6 (CD44v6) represents a viable strategy for the therapy and/or early diagnosis of metastatic cancers of the epithelium (e.g. gastric and colorectal cancer). We developed and characterized poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles (NPs) modified with polyethylene glycol (PEG) and engrafted, by site-directed conjugation, with an engineered human Fab that specifically target human CD44v6 (v6 Fab-PLGA NPs). The v6 Fab-PLGA NPs displayed spherical morphology around 300 nm and were negatively charged. They strongly bound to a CD44v6-derived peptide and, more importantly, to cells that endogenously and exogenously express CD44v6, but not to non-expressing cells and cells expressing the standard isoform of CD44. The v6 Fab-PLGA NPs also recognized CD44v6 in tumor sections from cells grown subcutaneously within mice. The NPs had nominal cytotoxicity at 50 µg/mL and withstood simulated intestinal fluid exposure. Interestingly, v6 Fab-PLGA NPs cryopreserved in 10% trehalose and stored maintained specific cell binding. In conclusion, we envision NPs targeting CD44v6 as potential in vivo diagnostic agents and/or as anti-cancer agents in patients previously stratified with CD44v6+ carcinomas. STATEMENT OF SIGNIFICANCE: The v6 Fab-PLGA NPs displayed many favorable qualities as a potential CD44v6-targeted drug and/or diagnostic delivery agent. The NPs were designed for optimal ligand orientation and for immediate administration into humans. v6 Fab-PLGA NPs strongly bound to cells that endogenously and exogenously express CD44v6, but not to non-expressing cells and cells expressing the standard isoform of CD44. Binding ability was retained after freeze-drying and long-term storage, providing evidences on the stability of Fab-functionalized NPs. These NPs can potentially be used as an in vivo diagnostic from parenteral or oral/rectal administration.

Optimization of Hericium erinaceus polysaccharide-loaded Poly (lactic-co-glycolicacid) nanoparticles by RSM and its absorption in Caco-2 cell monolayers.

In present study, HEP was successfully encapsulated into the Poly (lactic-coglycolicacid) (PLGA) to constitute the HEP-PLGA. The effects of three independent factors (the proper range of ratio of organic phase (o) to internal water phase (w1) (X1), ratio of external water phase (w2) to the primary emulsion (PE) (X2), and the concentration of PLGA (X3) on the extraction yield of encapsulation efficiency (EE) from the HEP was optimized using response surface methodology. The optimal extraction conditions for HEP-PLGA were determined as follows: X1: 8:1, X2: 7:1 and X3: 20 mg·mL-1. Under these optimal conditions, the mean experimental EE 90.86 ±â€¯0.576% was corresponded well with the predicted value of 91.81%. In addition, to investigate the transport properties of HEP and HEP-PLGA using a Caco-2 cell monolayer, and study the roles of the efflux transporters (P-gp) during the transport process. These results suggested that HEP can be absorbed more efficiently when encapsulated within the PLGA. These findings highlight the potential to the application of HEP in the formulation of functional foods. These results provide strategies in designing high absorbed polysaccharides with bioactive benefits.

Chitosan coated PLGA nanoparticles amplify the ocular hypotensive effect of forskolin: Statistical design, characterization and in vivo studies.

PURPOSE: Enhancing the ocular hypotensive effect of forskolin (FK) by means of biodegradable chitosan (CS) coated poly lactic-co-glycolic acid (PLGA) nanoparticles (NP's). METHODS: One step emulsion-sonication process was employed for the formulation of CS-PLGA NP's with optimization being carried out by employing a four factor four level Box Behnken Design. The physical and spectral characterization, drug release, permeation, confocal and ocular tolerance studies (ex-vivo &in vivo) were performed. The corneal retention was assessed by gamma scintigraphic analysis and dexamethasone induced glaucamotous rabbit's intraocular pressure (IOP) was measured by means of Schiotz tonometer. RESULTS AND DISCUSSION: Particle size of optimized CS-PLGA NP's was found as 201.56 ±â€¯10.92 nm with a good PDI and positive zeta potential value. Entrapment efficiency and drug loading were found to be 72.32 ±â€¯1.12% and 28.39 ±â€¯1.67% respectively. Spectral characterization confirmed the purity and encapsulation of the drug within polymeric system. Sustained drug release and enhanced permeation profile was observed with maximum depth penetration. Ocular tolerance studies explicated its safe use. Scintigraphy studies indicated longer retention of CS-PLGA NP's while increased effectiveness after single instillation in reducing the intraocular pressure was observed. CONCLUSION: CS-PLGA-NP's could be successfully formulated and are an excellent vehicle for FK in ocular delivery.

Nanoparticle-based delivery of carbamazepine: A promising approach for the treatment of refractory epilepsy.

Resistance to antiepileptic drugs (AEDs) is a major clinical problem. The overexpression of P-glycoprotein (Pgp), one of the main transporters limiting the entry of xenobiotics into the brain, is among the factors contributing to the AED resistance. Presently, there is no consensus on the interaction of carbamazepine (CBZ) with the Pgp. This study investigates the effect of the Pgp inhibitor verapamil on the anticonvulsant effect of CBZ and its nanoparticulate formulation in the rat model of isoniazid-induced epilepsy. Verapamil significantly increased the anticonvulsant effect of CBZ and reduced its effective dose by at least 30% (from 30 mg/kg to 20 mg/kg). Binding of carbamazepine to the poloxamer 188-coated PLGA nanoparticles enabled a 30-fold increase of its anticonvulsive effect, as compared to the free drug. The inhibition of Pgp did not influence the effectivity of carbamazepine encapsulated in nanoparticles.

Preparation and in vitro/in vivo evaluation of PLGA microspheres containing norquetiapine for long-acting injection.

BACKGROUND: Norquetiapine (N-desalkyl quetiapine, NQ) is an active metabolite of quetiapine with stable pharmacokinetic and pharmacological properties. However, its short half-life is a drawback for clinical applications, and long-acting formulations are required. PURPOSE: The objectives of this study were to prepare improved entrapment efficiency NQ freebase microspheres by the solvent evaporation method with poly(d,l-lactic-co-glycolic acid) (PLGA) as a release modulator and to evaluate their physicochemical and in vitro/in vivo release properties. METHODS: NQ freebase PLGA (1:5 w/w) formulations were prepared by the oil-in-water (o/w) emulsion-solvent evaporation method. A solution of the drug and PLGA in 9:1 v/v dichloromethane:ethanol was mixed with 0.2% polyvinyl alcohol and homogenized at 2,800 rpm. The emulsion was stirred for 3 h to dilute and evaporate the solvent. After that, the resulting product was freeze-dried. Drug-loading capacity was measured by the validated RP-HPLC method. The surface morphology of the microspheres was observed by scanning electron microscopy (SEM), and the physicochemical properties were evaluated by differential scanning calorimetry, powder X-ray diffraction, and Fourier-transform infrared spectroscopy particle size distribution. The in vitro dissolution test was performed using a rotary shaking bath at 37°C, with constant shaking at 50 rpm in sink condition. RESULTS: The NQ freebase microspheres prepared by o/w emulsion-solvent evaporation showed over 30% efficiency. NQ was confirmed to be amorphous in the microspheres by powder X-ray diffraction and differential scanning calorimetry. Special chemical interaction in the microspheres was not observed by FT-IR. The in vitro dissolution test demonstrated that the prepared microspheres' release properties were maintained for more than 20 days. The in vivo test also confirmed that the particles' long acting properties were maintained. Therefore, good in vitro-in vivo correlation was established. CONCLUSION: In this study, NQ freebase-PLGA microspheres showed potential for the treatment of schizophrenia for long-periods.

Injectable PLGA Adefovir microspheres; the way for long term therapy of chronic hepatitis-B.

For patient convenience, sustained release Adefovir Poly-d,l-lactic-co-glycolic acid (PLGA) microspheres were formulated to relieve the daily use of the drug which is a problem for patients treated from chronic hepatitis-B. PLGA microspheres were prepared and characterized by entrapment efficiency, particle size distribution and scanning electron microscopy (SEM). In-vitro release and in-vivo studies were carried out. Factors such as drug: polymer ratio, polymer viscosity and polymer lactide content were found to be important variables for the preparation of PLGA Adefovir microspheres. Fourier transform infrared (FTIR) analysis and differential scanning calorimetry (DSC) were performed to determine any drug-polymer interactions. One way analysis of variance (ANOVA) was employed to analyze the pharmacokinetic parameters after intramuscular injection of the pure drug and the selected PLGA microspheres into rats. FTIR and DSC revealed a significant interaction between the drug and the polymer. Reports of SEM before and after 1 and 24 h release showed that the microspheres had nonporous smooth surface even after 24 h release. The entrapment efficiency ranged between 55.83 and 86.95% and in-vitro release studies were continued for 16, 31 and 90 days. The pharmacokinetic parameters and statistical analysis showed a significant increase in the Tmax, AUC0-t and MRT, and a significant decrease in the Cmax of the tested formulation (p < 0.05). Results demonstrated that PLGA Adefovir microspheres could be used for long-term treatment of chronic hepatitis-B instead of the daily dose used by the patient.

Oral insulin delivery, the challenge to increase insulin bioavailability: Influence of surface charge in nanoparticle system.

Oral administration of insulin increases patient comfort and could improve glycemic control thanks to the hepatic first passage. However, challenges remain. The current approach uses poly (d, lactic-co-glycolic) acid (PLGA) nanoparticles (NPs), an effective drug carrier system with a long acting profile. However, this system presents a bioavailability of less than 20% for insulin encapsulation. In this context, physico-chemical parameters like surface charge could play a critical role in NP uptake by the intestinal barrier. Therefore, we developed a simple method to modulate NP surface charge to test its impact on uptake in vitro and finally on NP efficiency in vivo. Various NPs were prepared in the presence (+) or absence (-) of polyvinyl alcohol (PVA), sodium dodecyl sulfate (SDS), and/or coated with chitosan chloride. In vitro internalization was tested using epithelial culture of Caco-2 or using a co-culture (Caco-2/RevHT29MTX) by flow cytometry. NPs were then administered by oral route using a pharmaceutical complex vector (100 or 250 UI/kg) in a diabetic rat model. SDS-NPs (-42 ±â€¯2 mV) were more negatively charged than -PVA-NPs (-22 ±â€¯1 mV) and chitosan-coated NPs were highly positively charged (56 ±â€¯2 mV) compared to +PVA particles (-2 ±â€¯1 mV), which were uncharged. In the Caco-2 model, NP internalization was significantly improved by using negatively charged NPs (SDS NPs) compared to using classical NPs (+PVA NPs) and chitosan-coated NPs. Finally, the efficacy of insulin SDS-NPs was demonstrated in vivo (100 or 250 UI insulin/kg) with a reduction of blood glucose levels in diabetic rats. Formulation of negatively charged NPs represents a promising approach to improve NP uptake and insulin bioavailability for oral delivery.

Controlled release of clarithromycin from PLGA microspheres enhances bone regeneration in rabbit calvaria defects.

This study evaluated the sustained release effect of clarithromycin-loaded in PLGA microspheres in a rabbit calvaria defect model. Four bone defects (ø5.0) were created in the calvaria of New Zealand White rabbits (n = 21, n = 7/time point). The defects were randomly designated to four groups. Group 1: No augmentation (sham), Group 2: beta-tricalcium phosphate (ß-TCP), Group 3: ß-TCP with 0.12 µg clarithromycin, and Group 4: ß-TCP with 6.12 µg PLGA microspheres loaded with 0.12 µg Clarithromycin. After 2, 4, and 12 weeks of healing, bone regeneration was evaluated using micro-computed tomography (µCT) and histology. Clarithromycin release from PLGA microspheres revealed sustained release for around 4 weeks with ∼50% release during the first week. Histologically, new bone formation was evident at 2 and 4 weeks of healing in all groups and bone formation increased as a function of healing time. At 12 weeks, Group 4 showed significantly higher amount of newly formed bone compared to Group 1. The µCT showed that Group 4 expressed significantly higher bone formation compared to Group 1 at all time points. The in vivo findings showed that ß-TCP with clarithromycin-loaded microspheres can enhance bone formation in bone defects. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 201-208, 2018.

Chemopreventive efficacy of curcumin-loaded PLGA microparticles in a transgenic mouse model of HER-2-positive breast cancer.

Curcumin has shown promising inhibitory activity against HER-2-positive tumor cells in vitro but suffers from poor oral bioavailability in vivo. Our lab has previously developed a polymeric microparticle formulation for sustained delivery of curcumin for chemoprevention. The goal of this study was to examine the anticancer efficacy of curcumin-loaded polymeric microparticles in a transgenic mouse model of HER-2 cancer, Balb-neuT. Microparticles were injected monthly, and mice were examined for tumor appearance and growth. Initiating curcumin microparticle treatment at 2 or 4 weeks of age delayed tumor appearance by 2-3 weeks compared to that in control mice that received empty microparticles. At 12 weeks, abnormal (lobular hyperplasia, carcinoma in situ, and invasive carcinoma) mammary tissue area was significantly decreased in curcumin microparticle-treated mice, as was CD-31 staining. Curcumin treatment decreased mammary VEGF levels significantly, which likely contributed to slower tumor formation. When compared to saline controls, however, blank microparticles accelerated tumorigenesis and curcumin treatment abrogated this effect, suggesting that PLGA microparticles enhance tumorigenesis in this model. PLGA microparticle administration was shown to be associated with higher plasma lactic acid levels and increased activation of NF-κΒ. The unexpected side effects of PLGA microparticles may be related to the high dose of the microparticles that was needed to achieve sustained curcumin levels in vivo. Approaches that can decrease the overall dose of curcumin (for example, by increasing its potency or reducing its clearance rate) may allow the development of sustained release curcumin dosage forms as a practical approach to cancer chemoprevention.

Preparation and characterization of surface-modified PLGA-polymeric nanoparticles used to target treatment of intestinal cancer.

Docetaxel (DTX), a cytotoxic taxane, is a poor water-soluble drug and exhibits less oral bioavailability. Current research investigates the effective transport, for DTX-loaded chitosan (CS)-coated-poly-lactide-co-glycolide (PLGA)-nanoparticles (NPs) (DTX-CS-PLGA-NPs) and DTX-PLGA-NPs as well as a novel third-generation P-gp inhibitor i.e. GF120918 (Elacridar), across intestinal epithelium with its successive uptake by the tumour cells in an in vitro model. The prepared NPs showed a spherical shape particle size i.e. <123.96 nm with polydispersity index (PDI) of <0.290 whereas for CS-coated NPs, the zeta potential was converted from negative to positive value along with a small modification in particle size distribution. The entrapment efficiency observed for DTX-CS-PLGA-NPs was 74.77%, whereas the in vitro release profile revealed an initial rapid DTX release followed by a sustained release pattern. For apparent permeability, DTX-CS-PLGA-NPs and DTX-PLGA-NPs along with GF120918 showed a five-fold (p < .01) and 2.2-fold enhancement, respectively, as observed in rat ileum permeation study. Similarly, for pharmacokinetic (PK) studies, higher oral bioavailability was observed from DTX-CS-PLGA-NPs (5.11-folds) and DTX-PLGA-NPs (3.29-folds) as compared with DTX-suspension (DTX-S). Cell uptake studies on A549 cells as performed for DTX-CS-PLGA-NPs and DTX-PLGA-NPs loaded with rhodamine 123 dye, exhibited enhanced uptake as compared with plain dye solution. The enhanced uptake for DTX-CS-PLGA-NPs and DTX-PLGA-NPs formulations in the presence of GF120918 was confirmed further with the help of confocal laser scanning microscopic images (CLSM). The potential of the third-generation novel P-gp inhibitor (GF120918) investigated for the effective delivery of DTX as well as investigation of permeability and uptake studies whereby a strong potential of GF120918 for effective oral delivery was established.

Small molecule delivery to solid tumors with chitosan-coated PLGA particles: A lesson learned from comparative imaging.

For polymeric nanoparticles (NPs) to deliver more drugs to tumors than free drug solution, it is critical that the NPs establish interactions with tumor cells and avoid removal from the tumors. Since traditional polyethylene glycol (PEG) surface layer interferes with the cell-NP interaction in tumors, we used a water-soluble and blood-compatible chitosan derivative called zwitterionic chitosan (ZWC) as an alternative surface coating for poly(lactic-co-glycolic acid) (PLGA) NPs. The ZWC-coated PLGA NPs showed pH-dependent surface charge profiles and differential cellular interactions according to the pH of the medium. The in vivo delivery of ZWC-coated NPs was evaluated in mice bearing LS174T-xenografts using magnetic resonance (MR) imaging and fluorescence whole body imaging, which respectively tracked iron oxide particles and indocyanine green (ICG) encapsulated in the NPs as tracers. MR imaging showed that ZWC-coated NPs were more persistent in tumors than PEG-coated NPs, in agreement with the in vitro results. However, the fluorescence imaging indicated that the increased NP retention in tumors by the ZWC coating did not significantly affect the ICG distribution in tumors due to the rapid release of the dye. This study shows that stable drug retention in NPs during circulation is a critical prerequisite to successful translation of the potential benefits of surface-engineered NPs.

Engineering PLGA nano-based systems through understanding the influence of nanoparticle properties and cell-penetrating peptides for cochlear drug delivery.

The properties of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and penetration enhancers play a deciding role in the inner ear drug delivery of NPs across the round window membrane (RWM). Thus, PLGA nano-based systems with a variety of particle sizes and surface chemistries and those combined with cell-penetrating peptides (CPPs) as penetration enhancers were devised to explore their impact on the cochlear drug delivery in vivo. First, we demonstrated that the properties of NPs dictated the extent of NP cochlear entry by near-infrared fluorescence imaging. NPs with the sizes of 150 and 300nm had faster entry than that of 80nm NPs. At 0.5h, among the NPs unmodified and modified with chitosan (CS), poloxamer 407 (P407) and methoxy polyethylene glycol, CS-PLGA-NPs (positive surface charge) carried payload to the cochlea fastest, whereas P407-PLGA-NPs (surface hydrophilicity) showed the greatest distribution in the cochlea at 24h. Compared to other CPPs (TAT, penetratin and poly(arginine)8), low molecular weight protamine (LMWP) performed an outstanding enhanced NP cellular uptake in HEI-OC1 cells and cochlear entry. More importantly, NPs with optimized properties and CPPs may be combined to improve RWM penetration. For the first time, we confirmed that the combination of P407-PLGA-NPs (mean diameter: 100-200nm) and LMWP provided a synergistic enhancement in NP entry to the organ of Corti and stria vascularis without inducing pathological alteration of cochlear tissues and RWM. Taken together, we propose an effective PLGA nano-based strategy for enhanced drug delivery to the inner ear tissues that combines hydrophilic molecule-modified NPs and CPPs, ultimately opening an avenue for superior inner ear therapy.

A pro-angiogenic degradable Mg-poly(lactic-co-glycolic acid) implant combined with rhbFGF in a rat limb ischemia model.

Site-specific controlled release of exogenous angiogenic growth factors, such as recombinant human basic fibroblast growth factor (rhbFGF), has become a promising approach to improve peripheral vascular disease. Here, we have developed an implant composed of spiral magnesium (Mg) and a coating made using poly(lactic-co-glycolic acid) (PLGA) with encapsulated rhbFGF (Mg-PLGA-rhbFGF). The encapsulated protein could release continually for 4weeks with well preserved bioactivity. We compared the angiogenic effect produced by Mg-PLGA-rhbFGF with that of a PLGA implant loaded with rhbFGF (PLGA-rhbFGF). The incorporation of Mg in the implant raised the microclimate pH in the polymer, which preserved the stability of rhbFGF. Mg-PLGA-rhbFGF exhibited advantages over PLGA-rhbFGF implant in terms of a cytocompatibility evaluation. An in vivo angiogenesis test further confirmed the efficacy of released rhbFGF. HE, CD31 and α-SMA staining revealed that the controlled release of rhbFGF from the Mg-PLGA-rhbFGF implant was superior in promoting angiogenesis compared with that of the PLGA-rhbFGF implant. Four weeks post-implantation, the capillary density of the Mg-PLGA-rhbFGF group was significantly higher than that of the PLGA-rhbFGF, control and the normal group (p<0.05, p<0.01 and p<0.01, respectively). Furthermore, the limb blood perfusion ratios of the Mg-PLGA-rhbFGF and PLGA-rhbFGF groups were dramatically increased, at 99.1±2.9% and 80.7±3.2%, respectively, whereas the ischemic limb did not recover in the control group. The biocompatibility of the implants was also evaluated. In conclusion, Mg-PLGA-based, sustained local delivery of rhbFGF promotes post-ischemic angiogenesis and blood flow recovery. The results suggest potential therapeutic usefulness of Mg-PLGA-rhbFGF for tissue ischemia. STATEMENT OF SIGNIFICANCE: Magnesium (Mg)-based implant has been already used in patients with critical limb ischemia. Site-specific controlled release of recombinant human basic fibroblast growth factor (rhbFGF), has become a promising approach to improve peripheral vascular disease. We report here on a novel combination implant composed of spiral magnesium and a coating made using poly(lactic-co-glycolic acid) (PLGA) with encapsulated rhbFGF (Mg-PLGA-rhbFGF). The preparation method does not involve any complex processes and results in a high encapsulation efficiency (approximately 100%). The degradation of metal Mg raise the microclimate pH in the PLGA polymer, which could well preserve the bioactivity of rhbFGF incorporated in the implant. Mg-PLGA-based, sustained local delivery of rhbFGF promotes post-ischemic angiogenesis and blood flow recovery in rat limb ischemic model. This work marks the first report for controlled release of rhbFGF in combination with metal Mg, and suggests potential therapeutic usefulness of Mg-PLGA-rhbFGF for tissue ischemia.

Cholera Toxin Subunit B Enabled Multifunctional Glioma-Targeted Drug Delivery.

Glioma is among the most formidable brain cancers due to location in the brain. Cholera toxin subunit B (CTB) is investigated to facilitate multifunctional glioma-targeted drug delivery by targeting the glycosphingolipid GM1 expressed in the blood-brain barrier (BBB), neovasulature, and glioma cells. When modified on the surface of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (CTB-NPs), CTB fully retains its bioactivity after 24 h incubation in the fresh mouse plasma. The formed protein corona (PC) of CTB-NP and plain PLGA nanoparticles (NP) after incubation in plasma is analyzed using liquid chromatography tandem massspectrometry (nano-LC-MS/MS). CTB modification does not alter the protein components of the formed PC, macrophage phagocytosis, or pharmacokinetic profiles. CTB-NP can efficiently penetrate the in vitro BBB model and target glioma cells and human umbilical vascular endothelial cells. Paclitaxel is loaded in NP (NP/PTX) and CTB-NP (CTB-NP/PTX), and their antiglioma effects are assessed in nude mice bearing intracranial glioma. CTB-NP/PTX can efficiently induce apoptosis of intracranial glioma cells and ablate neovasulature in vivo, resulting in significant prolongation of survival of nude mice bearing intracranial glioma (34 d) in comparison to those treated with NP/PTX (29 d), Taxol (24 d), and saline (21 d). The present study suggests a potential multifunctional glioma-targeted drug delivery system enabled by cholera toxin subunit B.

Folate-conjugated and pH-responsive polymeric micelles for target-cell-specific anticancer drug delivery.

In this study, we developed a folate (FA)-conjugated and pH-responsive active targeting micellar system for anti-cancer drug delivery. In this system, FA was attached to the terminal of the hydrophilic segment of poly(lactic acid)-poly(L-lysine) (PLA-PLL), and PLL was modified by a citric acid group. The FA receptor-mediated active targeting and electrostatic interaction between micelles and cell membrane due to a negative-to-positive charge reversal was combined in one micellar anti-cancer drug delivery system to enhance the tumour targeting and cellular internalisation of micelles. In vitro and in vivo anti-cancer studies demonstrated that the doxorubicin-loaded, FA-conjugated and pH-responsive polymeric micelles possess an enhanced and effective cancer efficiency. STATEMENT OF SIGNIFICANCE: Negatively charged nano-carriers prolonged anti-cancer drugs' blood circulation. However it is difficult to be internalised. Therefore, a negative-to-positive charged micelle surface could improve selectivity for tumour cells and increase uptake chance. In this study, we developed a folate (FA)-conjugated and pH-responsive active targeting micellar system for anti-cancer drug delivery. The FA receptor-mediated active targeting and electrostatic interaction between micelles and cell membrane due to a negative-to-positive charge reversal was combined in one micellar anti-cancer drug delivery system to enhance the tumour targeting and cellular internalisation of micelles. In vitro and in vivo anti-cancer studies demonstrated that the doxorubicin-loaded, FA-conjugated and pH-responsive polymeric micelles possess an enhanced and effective cancer efficiency.

Nanoparticles administered intrapericardially enhance payload myocardial distribution and retention.

Pharmacological therapies for cardiovascular diseases are limited by short-term pharmacokinetics and extra-cardiac adverse effects. Improving delivery selectivity specifically to the heart, wherein therapeutic drug levels can be maintained over time, is highly desirable. Nanoparticle (NP)-based pericardial drug delivery could provide a strategy to concentrate therapeutics within a unique, cardiac-restricted compartment to allow sustained drug penetration into the myocardium. Our objective was to explore the kinetics of myocardial penetration and retention after pericardial NP drug delivery. Fluorescently-tagged poly(lactic-co-glycolic acid) (PLGA) NPs were loaded with BODIPY, a fluorophore, and percutaneously administered into the pericardium via subxiphoid puncture in rabbits. At distinct timepoints hearts were examined for presence of NPs and BODIPY. PLGA NPs were found non-uniformly distributed on the epicardium following pericardial administration, displaying a half-life of ~2.5days in the heart. While NPs were mostly confined to epicardial layers, BODIPY was capable of penetrating into the myocardium, resulting in a transmural gradient. The distinct architecture and physiology of the different regions of the heart influenced BODIPY distribution, with fluorophore penetrating more readily into atria than ventricles. BODIPY proved to have a long-term presence within the heart, with a half-life of ~7days. Our findings demonstrate the potential of utilizing the pericardial space as a sustained drug-eluting reservoir through the application of nanoparticle-based drug delivery, opening several exciting avenues for selective and prolonged cardiac therapeutics.