Fabrication of 3-O-sn-Phosphatidyl-L-serine Anchored PLGA Nanoparticle Bearing Amphotericin B for Macrophage Targeting

Purpose

To fabricate, characterize and evaluate 3-O-sn-Phosphatidyl-L-serine (PhoS) anchored PLGA nanoparticles for macrophage targeted therapeutic intervention of VL.

Materials and Methods

PLGA-AmpB NPs were prepared by well-established nanoprecipitation method and decorated with Phos by thin film hydration method. Physico-chemical characterization of the formulation was done by Zetasizer nano ZS and atomic force microscopy.

Results

The optimized formulation (particle size, 157.3?±?4.64 nm; zeta potential, ? 42.51?±?2.11 mV; encapsulation efficiency, ～98%) showed initial rapid release up to 8 h followed by sustained release until 72 h. PhoS generated ‘eat-me’ signal driven augmented macrophage uptake, significant increase in in-vitro (with ～82% parasite inhibition) and in-vivo antileishmanial activity with preferential accumulation in macrophage rich organs liver and spleen were found. Excellent hemo-compatibility justified safety profile of developed formulation in comparison to commercial formulations.

Conclusion

The developed PhoS-PLGA-AmpB NPs have improved efficacy, and necessary stability which promisingly put itself as a better alternative to available commercial formulations for optimized treatment of VL.

     

Gelatin Nano-coating for Inhibiting Surface Crystallization of Amorphous Drugs

Purpose

Inhibit the fast surface crystallization of amorphous drugs with gelatin nano-coatings.

Methods

The free surface of amorphous films of indomethacin or nifedipine was coated by a gelatin solution (type A or B) and dried. The coating’s effect on surface crystallization was evaluated. Coating thickness was estimated from mass change after coating.

Results

For indomethacin (weak acid, pK_a?=?4.5), a gelatin coating of either type deposited at pH 5 and 10 inhibited its fast surface crystal growth. The coating thickness was 20?±?10 nm. A gelatin coating deposited at pH 3, however, provided no protective effect. These results suggest that an effective gelatin coating does not require that the drug and the polymer have opposite charges. The ineffective pH 3 coating might reflect the poor wetting of indomethacin’s neutral, hydrophobic surface by the coating solution. For nifedipine (weak base, pK_a?=?2.6), a gelatin coating of either type deposited at pH 5 inhibited its fast surface crystal growth.

Conclusions

Gelatin nano-coatings can be conveniently applied to amorphous drugs from solution to inhibit fast surface crystallization. Unlike strong polyelectrolyte coatings, a protective gelatin coating does not require strict pairing of opposite charges. This could make gelatin coating a versatile, pharmaceutically acceptable coating for stabilizing amorphous drugs.

     

Novel Gemcitabine Conjugated Albumin Nanoparticles: a Potential Strategy to Enhance Drug Efficacy in Pancreatic Cancer Treatment

Purpose

The present study reports a novel conjugate of gemcitabine (GEM) with bovine serum albumin (BSA) and thereof nanoparticles (GEM-BSA NPs) to potentiate the therapeutic efficacy by altering physicochemical properties, improving cellular uptake and stability of GEM.

Methods

The synthesized GEM-BSA conjugate was extensively characterized by NMR, FTIR, MALDI-TOF and elemental analysis. Conjugation mediated changes in structural conformation and physicochemical properties were analysed by fluorescence, Raman and CD spectroscopy, DSC and contact angle analysis. Further, BSA nanoparticles were developed from BSA-GEM conjugate and extensively evaluated against in-vitro pancreatic cancer cell lines to explore cellular uptake pathways and therapeutic efficacy.

Results

Various characterization techniques confirmed covalent conjugation of GEM with BSA. GEM-BSA conjugate was then transformed into NPs via high pressure homogenization technique with particle size 147.2 ± 7.3, PDI 0.16 ± 0.06 and ZP -19.2 ± 1.4. The morphological analysis by SEM and AFM revealed the formation of smooth surface spherical nanoparticles. Cellular uptake studies in MIA PaCa-2 (GEM sensitive) and PANC-1 (GEM resistant) pancreatic cell lines confirmed energy dependent clathrin internalization/endocytosis as a primary mechanism of NPs uptake. In-vitro cytotoxicity studies confirmed the hNTs independent transport of GEM in MIA PaCa-2 and PANC-1 cells. Moreover, DNA damage and annexin-V assay revealed significantly higher apoptosis level in case of cells treated with GEM-BSA NPs as compared to free GEM.

Conclusions

GEM-BSA NPs were found to potentiate the therapeutic efficacy by altering physicochemical properties, improving cellular uptake and stability of GEM and thus demonstrated promising therapeutic potential over free drug.

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Graphical Abstract ?

     

Reversion of Multidrug Resistance by Co-Encapsulation of Doxorubicin and Metformin in Poly(lactide-co-glycolide)-d-α-tocopheryl Polyethylene Glycol 1000 Succinate Nanoparticles

Purpose

P-glycoprotein (P-gp) mediated multidrug resistance (MDR) has been recognized as the main obstacle against successful cancer treatment. To address this problem, co-encapsulated doxorubicin (DOX) and metformin (Met) in a biodegradable polymer composed of poly(lactide-co-glycolide) (PLGA) and D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) was prepared. We reported in our previous study that Met inhibits P-gp in DOX resistant breast cancer (MCF-7/DOX) cells. TPGS is a bioactive compound which has also been shown to inhibit P-gp, further to its pharmaceutical advantages.

Methods

The DOX/Met loaded PLGA-TPGS nanoparticles (NPs) were prepared by double emulsion method and characterized for their surface morphology, size and size distribution, and encapsulation efficiencies of drugs in NPs.

Results

All NPs were found to be spherical-shaped with the size distribution below 100 nm and encapsulation efficiencies were 42.26?±?2.14% for DOX and 7.04?±?0.52% for Met. Dual drug loaded NPs showed higher cytotoxicity and apoptosis in MCF-7/DOX cells in comparison to corresponding free drugs. The higher cytotoxicity of dual drug loaded NPs was attributed to the enhanced intracellular drug accumulation due to enhanced cellular uptake and reduced drug efflux which was obtained by combined effects of Met and TPGS in reducing cellular ATP content and inhibiting P-gp.

Conclusion

Simultaneous delivery of DOX and Met via PLGA-TPGS NPs would be a promising approach to overcome MDR in breast cancer chemotherapy.

     

Preparation,Physicochemical Characterization and Anti-fungal Evaluation of Nystatin-Loaded PLGA-Glucosamine Nanoparticles

Purpose

Nystatin loaded PLGA and PLGA-Glucosamine nanoparticles were formulated. PLGA were functionalized with Glucosamine (PLGA-GlcN) to enhance the adhesion of nanoparticles to Candida Albicans (C.albicans) cell walls.

Method

Quasi-emulsion solvent diffusion method was employed using PLGA and PLGA-GlcN with various drug–polymer ratios for the preparation of nanoparticles. The nanoparticles were evaluated for size, zeta potential, polydispersity index, drug crystallinity, loading efficiency and release properties. DSC, SEM, XRPD, ¹H-NMR, and FT-IR were performed to analyze the physicochemical properties of the nanoparticles. Antifungal activity of the nanoparticles was evaluated by determination of MICs against C.albicans.

Results

The spectra of ¹H-NMR and FT-IR analysis ensured GlcN functionalization on PLGA nanoparticles. SEM characterization confirmed that particles were in the nanosize range and the particle size for PLGA and PLGA-GlcN nanoparticles were in the range of 108.63?±?4.5 to 168.8?±?5.65 nm and 208.76?±?16.85 nm, respectively. DSC and XRPD analysis ensured reduction of the drug crystallinity in the nanoparticles. PLGA-GlcN nanoparticles exhibit higher antifungal activity than PLGA nanoparticles.

Conclusion

PLGA-GlcN nanoparticles showed more antifungal activity with appropriate physicochemical properties than pure Nystatin and PLGA nanoparticles.

     

Intra- and Extracellular Biosynthesis and Characterization of Iron Nanoparticles from Prokaryotic Microorganisms with Anticoagulant Activity

Background

The use of microorganisms for the synthesis of nanoparticles (NPs) is relatively new in basic research and technology areas.

Purpose

This work was conducted to optimized the biosynthesis of iron NPs intra- and extracellular by Escherichia coli or Pseudomonas aeruginosa and to evaluate their anticoagulant activity.

Study Design/Methods

The structures and properties of the iron NPs were investigated by Ultraviolet–visible (UV-vis) spectroscopy, Zeta potential, Dynamic light scattering (DLS), Field emission scanning electron microscope (FESEM)/ Energy dispersive X-ray (EDX) and transmission electron microscopy (TEM). Anticoagulant activity was determined by conducting trials of Thrombin Time (TT), Activated Partial Prothrombin Time (APTT) and Prothrombin Time (PT).

Results

UV-vis spectrum of the aqueous medium containing iron NPs showed a peak at 275 nm. The forming of iron NPs was confirmed by FESEM/ EDX, and TEM. The morphology was spherical shapes mostly with low polydispersity and the average particle diameter was 23?±?1 nm. Iron NPs showed anticoagulant activity by the activation of extrinsic pathway.

Conclusion

The eco-friendly process of biosynthesis of iron NPs employing prokaryotic microorganisms presents a good anticoagulant activity. This could be explored as promising candidates for a variety of biomedical and pharmaceutical applications.

     

Effect of Nanoparticle Surface on the HPLC Elution Profile of Liposomal Nanoparticles

Purpose

Nanoparticles have been used in diverse areas, and even broader applications are expected in the future. Since surface modification can influence the configuration and toxicity of nanoparticles, a rapid screening method is important to ensure nanoparticle quality.

Methods

We examined the effect of the nanoparticle surface morphology on the HPLC elution profile using two types of 100-nm liposomal nanoparticles (AmBisome^? and DOXIL^?).

Results

These 100-nm-sized nanoparticles eluted before the holdup time (about 4 min), even when a column packed with particles with a relatively large pore size (30 nm) was used. The elution time of the nanoparticles increased with pegylation of the nanoparticles and protein adsorption to the nanoparticles; however, the nanoparticles still eluted before the holdup time.

Conclusions

The results of this study indicate that HPLC is a suitable tool for rapid evaluation of the surface of liposomal nanoparticles.

     

Arginine-α, β-dehydrophenylalanine Dipeptide Nanoparticles for pH-Responsive Drug Delivery

Purpose

Nanoparticles (NPs) exhibiting responsiveness towards pH variations in organs, tissue microenvironments and cellular compartments can significantly add on to the drug delivery potential. Here, we have developed NPs from an amphipathic dipeptide, Arginine-α, β-dehydrophenylalanine (RΔF), and tried to explore their pH responsive drug delivery potential in various cancer cells.

Methods

RΔF-NPs were architectured by harnessing the process of molecular self-assembly followed by the assessment of effect of pH on NPs morphology using zetasizer, SEM and CD. FTIR and PXRD analysis of the dipeptide and doxorubicin (Dox) were carried out for compatibility assessment followed by encapsulation of Dox in RΔF-NPs. RΔF-Dox-NPs were evaluated for pH dependent release as well as for in-vitro cellular internalization and efficacy in cancer cells.

Results

RΔF self-assembled to form monodispersed particles at pH 7. SEM analysis revealed a loss of overall particle morphology along with particle aggregation at highly acidic and basic pH respectively. The NPs demonstrated a slow and sustained release behaviour at pH 7 (97.64?±?4.71% after 36 h) in comparison to pH 2 (90.27?±?1.45% after 8 h) and pH 10 (96.39?±?3.87% after 12 h). In-vitro efficacy studies carried-out in various cancer cells revealed that RΔF-Dox-NPs exhibited higher efficacy with 1.65, 1.95 and 13.34 fold lower IC₅₀ values in comparison to Dox in C6, HCT-116 and AGS cell lines.

Conclusions

RΔF-Dox-NPs with higher drug release at acidic pH, enhanced internalization in cancer cells along with higher cytotoxic potential can act as effective pH responsive drug delivery systems.

     

Drug Interaction Between Clopidogrel and Ranitidine or Omeprazole in Stable Coronary Artery Disease: A Double-Blind,Double Dummy,Randomized Study

Background

Proton-pump inhibitors (PPIs) are often prescribed to patients receiving dual antiplatelet therapy (DAPT). However, this class of medication, especially omeprazole, has been associated with a reduction in clopidogrel efficacy, leading many clinicians to substitute omeprazole with ranitidine.

Objectives

Our objective was to compare the antiplatelet effect of clopidogrel before and after the addition of omeprazole or ranitidine.

Methods

We measured platelet aggregability at baseline and after 1 week of clopidogrel 75 mg daily. Subjects were then randomized in a double-blinded, double-dummy fashion to omeprazole 20 mg twice daily (bid) or ranitidine 150 mg bid. We repeated aggregability tests after 1 additional week, using VerifyNow P2Y12? (Accumetrics; San Diego, CA, USA), depicting aggregability as percent inhibition of platelet aggregation (IPA).

Results

We enrolled 41 patients in the omeprazole group and 44 in the ranitidine group. IPA was significantly decreased after the addition of omeprazole to clopidogrel (from 26.3 ± 32.9 to 17.4 ± 33.1 %; p = 0.025), with no statistical significant changes observed in the ranitidine group (from 32.6 ± 28.9 to 30.1 ± 31.3 %; p = 0.310). The comparison of IPA in both groups at the end of the follow-up showed a trend toward significance (p = 0.07, 95 % confidence interval [CI] ?1.19 to 26.59); after excluding homozygous patients for 2C19*2 genotype, the comparison of IPA between the groups reached statistical significance (32.7 ± 30.8 vs. 17.7 ± 33.4 %, respectively, for ranitidine and omeprazole groups; p = 0.04).

Conclusions

Unlike omeprazole, ranitidine did not influence platelet aggregability response to clopidogrel.

Clinical Trial Registration

NCT01896557.

     

A Comparison of Two Methods for the Preparation Cefquinome-Loaded Gelatin Microspheres for Lung Targeting

Purpose

The aim of this study was to prepare CEQ-loaded gelatin microspheres and compare two preparation methods, evaluate targeting to the lungs.

Methods

Gelatin microspheres containing CEQ were prepared by an emulsion cross-linking method (ECLM) and a spray-drying method (SDM) and were characterized in terms of morphology, size, drug-loading coefficient, encapsulation ratio and in vitro release.

Results

The microspheres prepared by ECLM gave a drug loading (DL) of 19.4?±?2.4% and an entrapment efficiency (EE) of 80.8?±?3.2%. The microspheres prepared by SDM resulted in a DL value of 20.8?±?2.7% and an EE of 95.3?±?3.8%. The average particle size of microspheres was 7-30 μm by both methods and both preparations sustained CEQ release for 36 h in the target tissue (lungs). The in vitro release profile of the microspheres matched the Korsmeyer-Peppas release pattern. In vivo studies identified the lung as the target tissue and the region of maximum CEQ release. Histopathological examination showed a partial lung inflammation that disappeared spontaneously as the microspheres were biodegraded. In general, the formulations were safe.

Conclusion

The well-sustained CEQ release from the microspheres revealed its suitability as a drug delivery vehicle that minimized injury to healthy tissues while achieving the accumulation of therapeutic drug for lung targeting. The intravenous administration of CEQ gelatin microspheres prepared by SDM is of potential value in treating lung diseases in animals.

     

Bioreducible Poly(Amino Ethers) Based mTOR siRNA Delivery for Lung Cancer

Purpose

Lung cancer is one of the leading causes of deaths in the United States, but currently available therapies for lung cancer are associated with reduced efficacy and adverse side effects. Small interfering RNA (siRNA) can knock down the expression of specific genes and result in therapeutic efficacy in lung cancer. Recently, mTOR siRNA has been shown to induce apoptosis in NSCLC cell lines but its use is limited due to poor stability in biological conditions.

Methods

In this study, we modified an aminoglyocisde-derived cationic poly (amino-ether) by introducing a thiol group using Traut’s reagent to generate a bio-reducible modified–poly (amino-ether) (mPAE). The mPAE polymer was used to encapsulate mTOR siRNA by nanoprecipitation method, resulting in the formation of stable and bio-reducible nanoparticles (NPs) which possessed an average diameter of 114 nm and a surface charge of approximately +27 mV.

Results

The mTOR siRNA showed increased release from the mTS-mPAE NPs in the presence of 10 mM glutathione (GSH). The polymeric mTS-mPAE-NPs were also capable of efficient gene knockdown (60 and 64%) in A549 and H460 lung cancer cells, respectively without significant cytotoxicity at 30 μg/ml concentrations. The NPs also showed time-dependent cellular uptake for up to 24 h as determined using flow cytometry. Delivery of the siRNA using these NPs also resulted in significant inhibition of A549 and H460 cell proliferation in vitro, respectively.

Conclusions

The results demonstrate that the mPAE polymer based NPs show strong potential for siRNA delivery to lung cancer cells. It is anticipated that future modification can help improve the efficacy of nucleic acid delivery, leading to higher inhibition of lung cancer growth in vitro and in vivo.

     

A Comparative Study of Orally Delivered PBCA and ApoE Coupled BSA Nanoparticles for Brain Targeting of Sumatriptan Succinate in Therapeutic Management of Migraine

Purpose

The present investigation aimed at brain targeting of sumatriptan succinate (SS) for its optimal therapeutic effect in migraine through nanoparticulate drug delivery system using poly (butyl cyanoacrylate) (PBCA) and bovine serum albumin linked with apolipoprotein E3 (BSA-ApoE).

Method

The study involved formulation optimization of PBCA nanoparticles (NPs) using central composite design for achieving minimum particle size, maximum entrapment efficiency along with sustained drug release. SS incorporated in BSA-ApoE NPs (S-AA-NP) were prepared by desolvation technique and compared with SS loaded polysorbate 80 coated optimized PBCA NPs (FP_opt) in terms of their brain uptake potential, upon oral administration in male Wistar rats. The NPs were characterized by FTIR, thermal, powder XRD and TEM analysis.

Results

The in vivo studies of FP_opt and S-AA-NP on male Wistar rats demonstrated a fairly high brain/plasma drug ratio of 9.45 and 12.67 respectively 2 h post oral drug administration. The behavioural studies on male Swiss albino mice affirmed the enhanced anti-migraine potential of S-AA-NP than FP_opt (P?<?0.001).

Conclusion

The results of this work, therefore, indicate that BSA-ApoE NPs are significantly better than polysorbate 80 coated PBCA NPs for brain targeting of SS (P?<?0.05) and also offer an improved therapeutic strategy for migraine management.

     

Synthesis and Characterization of Poly(2-hydroxyethylmethacrylate) Contact Lenses Containing Chitosan Nanoparticles as an Ocular Delivery System for Dexamethasone Sodium Phosphate

Purpose

Dexamethasone sodium phosphate (DXP) is an anti-inflammatory drug commonly used to treat acute and chronic ocular diseases. It is routinely delivered using eye-drops, where typically only 5% of the drug penetrates the corneal epithelium. The bioavailability of such ophthalmic drugs can be enhanced significantly using contact lenses incorporating drug-loaded nanoparticles (NPs).

Methods

The mechanism of release from chitosan NPs (CS-NPs), synthesized by ionic gelation, was studied in vitro. The DXP loaded CS-NPs were subsequently entrapped in contact lenses and the optical and drug-release properties were assessed.

Results

DXP release from CS-NPs followed diffusion and swelling controlled mechanisms, with an additional proposed impact from the electrostatic interaction between the drug and the CS-NPs. The release rate was found to increase with an increase in drug loading from 20 to 50 wt%. However, an inverse effect was observed when initial loading increased to 100 wt%. NP-laden lenses were optically clear (95–98% transmittance relative to the neat contact lens) and demonstrated sustained DXP release, with approximately 55.73% released in 22 days.

Conclusions

The release profile indicated that drug levels were within the therapeutic requirement for anti-inflammatory use. These results suggest that these materials might be a promising candidate for the delivery of DXP and other important ophthalmic therapeutics.

     

Doxorubicin-Bound Albumin Nanoparticles Containing a TRAIL Protein for Targeted Treatment of Colon Cancer

Purpose

We developed a new nanoparticle formulation comprised of human serum albumin (HSA) for co-delivery of doxorubicin (Dox) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with the goal of apoptotic synergy in the treatment of colon cancer.

Methods

TRAIL (0.2, 0.4, 1.0%)- and Dox-loaded HSA nanoparticles (TRAIL/Dox HSA NPs) were prepared by using the nab^TM technology. Morphological and physicochemical characterizations were investigated by dynamic light scattering and transmission electron microscopy. Synergistic cytotoxicity, apoptotic activity, and potential penetration into mass tumor were determined in HCT116 cell-based systems. Furthermore, antitumor efficacy and tumor targeting were also investigated.

Results

TRAIL/Dox HSA NPs were uniformly spherical with sizes of 60?~?120 nm. The encapsulation efficacy of Dox and TRAIL was 68.9–77.2% and 80.4–86.0%, respectively. TRAIL 1.0%/Dox HSA NPs displayed the best inhibition of HCT116 colon cancer cells; inhibition was 6 times higher than achieved with Dox HSA NPs. The TRAIL 1.0%/Dox HSA NPs formulation was studied further. Flow cytometry analysis and TUNEL assay revealed that TRAIL 1.0%/Dox HSA NPs had markedly greater apoptotic activity than Dox HSA NPs. In HCT116 tumor-bearing BALB/c nu/nu mice, TRAIL 1.0%/Dox HSA NPs had significantly higher antitumor efficacy than Dox HSA NPs (tumor volume; 933.4 mm³ vs. 3183.7 mm³, respectively). TRAIL 1.0%/Dox HSA NPs penetrated deeply into tumor masses in a HCT116 spheroid model and localized in tumor sites after tail vein injection.

Conclusions

Data indicate that TRAIL 1.0%/Dox HSA NPs offer advantages of co-delivery of Dox and TRAIL in tumors, with potential synergistic apoptosis-based anticancer therapy.

     

Budesonide Loaded PLGA Nanoparticles for Targeting the Inflamed Intestinal Mucosa—Pharmaceutical Characterization and Fluorescence Imaging

Purpose

The purpose of this study was to evaluate the specifically targeted efficiency of budesonide loaded PLGA nanoparticles for the treatment of inflammatory bowel disease (IBD).

Methods

The nanoparticles were prepared by an oil/water (O/W) emulsion evaporation technique. The nanoparticles were characterized for their size, shape and in vitro drug release profile. Solid state characterization was carried out by differential scanning calorimetry (DSC) and X-ray Power diffraction (XPRD). In order to evaluate the targeted efficiency of nanoparticles, a particle localization study in the healthy and in the inflamed colon was determined in vivo. These data were complemented by cryo-sections.

Results

Nanoparticles were 200?±?05 nm in size with a smooth and spherical shape. The encapsulation efficiency was around 85?±?3.5%, which was find-out by both, direct and indirect methods. Release of budesonide from the nanoparticles showed a biphasic release profile with an initial burst followed by sustained release. XPRD data revealed that the drug in the polymer matrix existed in crystalline state. Nanoparticles accumulation in inflamed tissues was evaluated by in-vivo imaging system and it was found that particles are accumulated in abundance at the site of inflammation when compared to the healthy group.

Conclusion

The study demonstrates that the budesonide loaded PLGA nanoparticles are an efficient delivery system for targeted drug delivery to the inflamed intestinal mucosa.

     

Functionalization of PLGA Nanoparticles with 1,3-β-glucan Enhances the Intracellular Pharmacokinetics of Rifampicin in Macrophages

Purpose

Mycobacterium tuberculosis which causes tuberculosis, is primarily resident within macrophages. 1,3-β-glucan has been proposed as a ligand to target drug loaded nanoparticles (NPs) to macrophages. In this study we characterized the intracellular pharmacokinetics of the anti-tubercular drug rifampicin delivered by 1,3-β-glucan functionalized PLGA NPs (Glu-PLGA). We hypothesized that Glu-PLGA NPs would be taken up at a faster rate than PLGA NPs, and consequently deliver higher amounts of rifampicin into the macrophages.

Methods

Carbodiimide chemistry was employed to conjugate 1,3-β-glucan and rhodamine to PLGA. Rifampicin loaded PLGA and Glu-PLGA NPs as well as rhodamine functionalized PLGA and Glu-PLGA NPs were synthesized using an emulsion solvent evaporation technique. Intracellular pharmacokinetics of rifampicin and NPs were evaluated in THP-1 derived macrophages. A pharmacokinetic model was developed to describe uptake, and modelling was performed using ADAPT 5 software.

Results

The NPs increased the rate of uptake of rifampicin by a factor of 17 and 62 in case of PLGA and Glu-PLGA, respectively. Expulsion of NPs from the macrophages was also observed, which was 3 fold greater for Glu-PLGA NPs than for PLGA NPs. However, the ratio of uptake to expulsion was similar for both NPs. After 24 h, the amount of rifampicin delivered by the PLGA and Glu-PLGA NPs was similar. The NPs resulted in at least a 10-fold increase in the uptake of rifampicin.

Conclusions

Functionalization of PLGA NPs with 1,3-β-glucan resulted in faster uptake of rifampicin into macrophages. These NPs may be useful to achieve rapid intracellular eradication of Mycobacterium tuberculosis.

     

Progesterone PLGA/mPEG-PLGA Hybrid Nanoparticle Sustained-Release System by Intramuscular Injection

Purpose

To prepare sustained-release PLGA/mPEG-PLGA hybrid nanoparticles of progesterone (PRG), and evaluate the descending required administration dosage in vivo.

Methods

PRG hybrid nanoparticles (PRG H-NPs) based on PLGA/mPEG-PLGA were compared with PRG nanoparticles (PRG-NPs) of pure PLGA as the matrix and PRG-oil solutions. Nanoparticles (NPs) were formed by the method of nanoemulsion, and the pharmacokinetics of the sustained-release PRG H-NPs in male Sprague dawley (SD) rats were investigated. The rats were randomly divided into four groups, each group received: single dose of PRG H-NPs (14.58 mg/kg, i.m.) and PRG-NPs (14.58 mg/kg, i.m.), repeated dosing for 7 days of PRG-oil (2.08 mg/kg, i.m.) solution (Oil-L) and a higher dosage of PRG-oil (6.24 mg/kg, i.m.) solution (Oil-H), respectively.

Results

In the pharmacokinetic test, the PRG H-NPs exhibited a comparatively good sustained-release effect against the PRG-NPs without mPEG-PLGA and PRG-oil solution. The pharmacokinetic parameters of the PRG H-NPs, PRG-NPs, Oil-L and Oil-H were AUC_0–t(ng·h·mL^?1) 8762.1, 1546.1, 1914.5, and 12,138.9, t_1/2 (h)52.7, 44.1, 8.4 and 44.6 respectively.

Conclusions

Owing to the modification of PEG, PRG H-NPs can act as safe delivery platforms for sustained-release of drugs with a lower dosage required.

     

Preparation of Drug-Loaded PLGA-PEG Nanoparticles by Membrane-Assisted Nanoprecipitation

Purpose

The aim of this work is to develop a scalable continuous system suitable for the formulation of polymeric nanoparticles using membrane-assisted nanoprecipitation. One of the hurdles to overcome in the use of nanostructured materials as drug delivery vectors is their availability at industrial scale. Innovation in process technology is required to translate laboratory production into mass production while preserving their desired nanoscale characteristics.

Methods

Membrane-assisted nanoprecipitation has been used for the production of Poly[(D,L lactide-co-glycolide)-co-poly ethylene glycol] diblock) (PLGA-PEG) nanoparticles using a pulsed back-and-forward flow arrangement. Tubular Shirasu porous glass membranes (SPG) with pore diameters of 1 and 0.2 μm were used to control the mixing process during the nanoprecipitation reaction.

Results

The size of the resulting PLGA-PEG nanoparticles could be readily tuned in the range from 250 to 400 nm with high homogeneity (PDI lower than 0.2) by controlling the dispersed phase volume/continuous phase volume ratio. Dexamethasone was successfully encapsulated in a continuous process, achieving an encapsulation efficiency and drug loading efficiency of 50% and 5%, respectively. The dexamethasone was released from the nanoparticles following Fickian kinetics.

Conclusions

The method allowed to produce polymeric nanoparticles for drug delivery with a high productivity, reproducibility and easy scalability.

     

Drug Delivery Nanoparticles with Locally Tunable Toxicity Made Entirely from a Light-Activatable Prodrug of Doxorubicin

Purpose

A major challenge facing nanoparticle-based delivery of chemotherapy agents is the natural and unavoidable accumulation of these particles in healthy tissue resulting in local toxicity and dose-limiting side effects. To address this issue, we have designed and characterized a new prodrug nanoparticle with controllable toxicity allowing a locally-delivered light trigger to convert the payload of the particle from a low to a high toxicity state.

Methods

The nanoparticles are created entirely from light-activatable prodrug molecules using a nanoprecipitation process. The prodrug is a conjugate of doxorubicin and photocleavable biotin (DOX-PCB).

Results

These DOX-PCB nanoparticles are 30 times less toxic to cells than doxorubicin, but can be activated to release pure therapeutic doxorubicin when exposed to 365 nm light. These nanoparticles have an average diameter of around 100 nm and achieve the maximum possible prodrug loading capacity since no support structure or coating is required to prevent loss of prodrug from the nanoparticle.

Conclusions

These light activatable nanoparticles demonstrate tunable toxicity and can be used to facilitate future therapy development whereby light delivered specifically to the tumor tissue would locally convert the nanoparticles to doxorubicin while leaving nanoparticles accumulated in healthy tissue in the less toxic prodrug form.

     

Effect of the Freezing Step in the Stability and Bioactivity of Protein-Loaded PLGA Nanoparticles Upon Lyophilization

Purpose

The freezing step in lyophilization is the most determinant for the quality of biopharmaceutics. Using insulin as model of therapeutic protein, our aim was to evaluate the freezing effect in the stability and bioactivity of insulin-loaded PLGA nanoparticles. The performance of trehalose, sucrose and sorbitol as cryoprotectants was evaluated.

Methods

Cryoprotectants were co-encapsulated with insulin into PLGA nanoparticles and lyophilized using an optimized cycle with freezing at ?80°C, in liquid nitrogen, or ramped cooling at ?40°C. Upon lyophilization, the stability of protein structure and in vivo bioactivity were assessed.

Results

Insulin was co-encapsulated with cryoprotectants resulting in particles of 243–394 nm, zeta potential of ?32 to ?35 mV, and an association efficiency above 90%. The cryoprotectants were crucial to mitigate the freezing stresses and better stabilize the protein. The insulin structure maintenance was evident and close to 90%. Trehalose co-encapsulated insulin-loaded PLGA nanoparticles demonstrated enhanced hypoglycemic effect, comparatively to nanoparticles without cryoprotectant and added with trehalose, due to a superior insulin stabilization and bioactivity.

Conclusions

The freezing process may be detrimental to the structure of protein loaded into nanoparticles, with negative consequences to bioactivity. The co-encapsulation of cryoprotectants mitigated the freezing stresses with benefits to protein bioactivity.