Baocheng Tian

Further investigation of nanostructured lipid carriers as an ocular delivery system: in vivo transcorneal mechanism and in vitro release study.

This study was designed to provide further understanding of transcorneal mechanism of nanostructured lipid carriers (NLC). NLC labeled with fluorescent marker rhodamine B or coumarin-6 were produced by a melt emulsification method. By confocal laser scanning microscopy (CLSM), the interaction of NLC with corneal epithelia was traced and evaluated in rabbits in vivo. Thermal stability of the markers and the amorphous state were detected using thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC). The labeled NLC were characterized to be solid spherical in shape with an average diameter of 70 nm and zeta potential of -8 mV by transmission electron microscopy and dynamic light scattering, respectively. CLSM results demonstrated NLC were not directly internalized by corneal epithelia, whereas the markers themselves transferred from NLC to corneal epithelia with subsequent staining of intracellular lipophilic compartments. Furthermore, the in vitro release study using liposome dispersions as mimic biomembranes demonstrated an efficient transfer of fluorescence marker into the liposomes. This implied the deceptive particle uptake was due to a collision-induced process, during which the rapid transfer of fluorescence marker occurred by forming a complex between the nanoparticles and the biomembranes. Thus, these evidences provide further insights into NLC as an ocular delivery system.

Multifunctional mesoporous silica nanoparticles modified with tumor-shedable hyaluronic acid as carriers for doxorubicin.

In this paper, a CD44-targeted and redox-responsive drug delivery system based on mesoporous silica nanoparticles (MSNs) was synthesized by conjugating tumor-shedable hyaluronic acid (HA) on the surface of MSNs via disulfide bonds. Doxorubicin hydrochloride (DOX·HCl) was physically encapsulated into HA modified MSNs (MSNs/SS/HA@DOX) as a model drug. MSNs/SS/HA@DOX (40nm) had a high drug loading (14.1%) and redox-responsive drug release property. The cellular uptake behaviors of MSNs/SS/HA@DOX by HeLa and LO2 cells were evaluated by confocal laser scanning microscopy (CLSM) and flow cytometry (FCM). MSNs/SS/HA@DOX exhibited higher cellular uptake efficacy via CD44-mediated endocytosis by HeLa cells (CD44 over-expressed cells) than by LO2 cells (CD44 deficient cells). The in vitro cytotoxicity assay demonstrated that MSNs/SS/HA@DOX exhibited higher cytotoxicity to HeLa cells than to LO2 cells. These results indicated that MSNs/SS/HA@DOX might be promising as a multifunctional drug delivery system to improve the anti-tumor efficacy of chemotherapeutic drugs.

A novel bi-layer ascending release osmotic pump tablet: In vitro investigation and in vivo investigation in pharmacokinetic study and IVIVC evaluation

This study was aimed to develop an ascending release push-pull osmotic pump (APOP) system with a novel mechanism and an easy manufacture process. Theoretical analysis showed that the key to obtain the non-zero order drug release was to break the balance between the drug suspension release rate in the drug layer and the swelling rate of the core, and an ascending drug release rate was achieved when the former was slower than the latter. A polymer (Polyox WSR N-12K) was introduced as a suspension agent in drug layer to slow down the hydration rate of drug layer. Influence of the composition of drug layer (PEO category, total amount, drug loading and fraction of NaCl), push layer (NaCl amount), and also the level of coating weight gain on the drug release profiles was investigated. Observation of hydration state was estimated by taking photos, and also was confirmed by the theories. Paliperidone was delivered successfully by APOP at an ascending release rate up to 20 h in vitro. The in vivo plasma concentration of paliperidone in beagle dogs increased gradually up to 19 h. The APOP with an easy manufacture process was a promising strategy to deliver drug at an ascending rate.

Hepatoma-targeting and pH-sensitive nanocarriers based on a novel D-galactopyranose copolymer for efficient drug delivery.

Smart nanoparticles based on the mechanisms of asialoglycoprotein (ASGP)-mediated endocytosis and pH-induced drug release were developed for the efficient treatment of hepatoma using a newly developed copolymer, methoxy-polyethylene glycols (PEG)-b-poly (d-galactopyranose) (MPEG-b-PMaIPG). The particles exhibited spherical shapes, uniform particle size distribution (100 ± 4.43 nm), negative zeta potential (-32.8 ± 0.23 mV), high drug loading (24.77 ± 2.68%) and encapsulation efficiency (66.12 ± 9.44%). The in vitro drug release was also investigated, resulting that the release of drug from particles depended on different pH value. In vitro cell cytotoxicity and hemolysis assays were conducted to confirm the safety of the MPEG-b-PMaIPG nanoparticles. Anticancer activity showed that DOX-loaded MPEG-b-PMaIPG nanoparticles exhibited a high antitumor activity toward HepG2 cells, which was similar to free DOX, while blank MPEG-b-PMaIPG nanoparticles were non-toxic up to a tested concentration of 1.0mg/mL. Confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) were used to verify the targeting efficiency of d-galactopyranose-modified nanoparticles. The results clearly demonstrated that d-galactopyranose-modified nanoparticles were taken up quickly by the HepG2 cells, which suggests that MPEG-b-PMaIPG nanoparticles with good biocompatibility and non-toxic for normal cells may be used as an effective cancer-targeting drug delivery system for chemotherapy.

Coordinated pH/redox dual-sensitive and hepatoma-targeted multifunctional polymeric micelle system for stimuli-triggered doxorubicin release: Synthesis, characterization and in vitro evaluation.

Multifunctional polymeric micelles self-assembled from a DOX-conjugated methoxypolyethylene glycols-b-poly (6-O-methacryloyl-D-galactopyranose)-disulfide bond-DOX (mPEG-b-PMAGP-SS-DOX) copolymer were prepared as an antitumor carrier for doxorubicin delivery, of which the chemical modification with disulfide bonds and hydrazone bonds allowed micelles to release doxorubicin (DOX) selectively at acidic pH and high redox conditions. The resulting micelles exhibited coordinated pH/redox dual-sensitive and hepatoma-targeted multifunction with sustaining stability in aqueous media. The multifunctional micelles showed spherical shapes with a mean diameter of 93 ± 2.08 nm, a low polydispersity index (PDI) of 0.21, a low CMC value of 0.095 mg/mL, a high drug grafting degree of 56.9% and a drug content of 39.0%. Remarkably, in vitro drug release studies clearly exhibited a pH and redox dual-sensitive drug release profile with significantly accelerated drug release treated with pH 5.0 and 10mM GSH (88.4% in 72 h) without drug burst release. The tumor proliferation assays indicated that DOX-grafted micelles, along with low cytotoxicity and well biocompatibility to normal cells up to a concentration of 10 μg/mL, inhibited the proliferation of HepG2 cells in a formulation-, time- and concentration-dependent manner in comparison with MCF-7 cells which was similar to free DOX. Anticancer activity releaved that the disulfide-modified micelles possessed much higher anti-hepatoma activity with a low IC50 value of 1.1 μg/mL following a 72 h incubation. Furthermore, the intracellular uptake tested by CLSM and FCM demonstrated that multifunctional polymeric micelles could be more efficiently taken up by HepG2 cells compared with MCF-7 cells, agreed well with MTT assays, suggesting these well-defined micelles provide a potential drug delivery system for dual-responsive controlled drug release and enhanced anti-hepatoma therapy.

N-Acetyl-D-glucosamine decorated polymeric nanoparticles for targeted delivery of doxorubicin: Synthesis, characterization and in vitro evaluation.

A novel targeting drug delivery system containing poly(styrene-alt-maleic anhydride)58-b-polystyrene130 (P(St-alt-MA)58-b-PSt130) as a copolymer backbone, N-acetyl glucosamine (NAG) as a targeting moiety was designed and synthesized. The NAG grafted copolymer (NAG-P(St-alt-MA)58-b-PSt130) was characterized by FTIR and (1)H NMR. The NAG-P(St-alt-MA)58-b-PSt130 nanoparticles exhibited spherical shapes with an average diameter about 56.27±0.43 nm, low critical micelle concentration of 0.028 mg/mL, negative zeta potential -41.46±0.99 mV, high drug loading 25.83±1.09% and encapsulation efficiency 69.69±3.98%. In vitro cell cytotoxicity was conducted to confirm the safety of the NAG-P(St-alt-MA)58-b-PSt130 nanoparticles. Confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) results showed that the NAG targeting moiety enhanced the internalization and targeting ability of NAG-P(St-alt-MA)58-b-PSt130 nanoparticles. Anticancer activity toward MCF-7 cells and HT29 cells showed that DOX-loaded NAG-P(St-alt-MA)58-b-PSt130 nanoparticles exhibited a higher antitumor activity compared to DOX-loaded P(St-alt-MA)58-b-PSt130 nanoparticles, which could attribute to NAG receptor-mediated endocytosis. These results suggest that the biocompatible and non-toxic NAG-P(St-alt-MA)58-b-PSt130 nanoparticles may be used as an effective targeting drug delivery system for cancer therapy.

A shell-crosslinked polymeric micelle system for pH/redox dual stimuli-triggered DOX on-demand release and enhanced antitumor activity

Based on targeted amphiphilic block copolymer N-acetyl glucosamine-poly (styrene-alt-maleic anhydride)58-b-polystyrene130 (NAG-P(St-alt-MA)58-b-PSt130), a pH/redox dual-triggered shell-crosslinked polymeric micelle system was constructed. The shell-crosslinked micelles (CLM) were prepared by post-crosslinking method to regulate drug release kinetics using cystamine as linkers between carboxy groups of the shell. Compared with non-crosslinked micelles (NCLM), CLM showed spherical shapes with little increased mean diameter of 102.40±0.54nm, low polydispersity index (PDI) of 0.19±0.36, enlarged zeta potential value from -41.46±0.99 to -9.31±0.50mV, indicating the successful modification of disulfide bonds in shell. In vitro drug release study clearly exhibited a pH and redox dual-sensitive drug release profile with significantly accelerated drug release under pH 5.0 and 10mM GSH conditions (46.84% in 96h) without burst release. Both CLM and NCLM showed quite different release profiles between physiological (pH 7.4) and tumoral microenvironment (pH 5.0), effectively avoiding the premature drug leakage and realizing on-demand drug release. The MTT assay implied that CLM presented a time- and concentration-dependent manner to inhibit proliferation of A549 and MCF-7 cells and much lower IC50 values in comparison with that of NCLM after 72h incubation. Both FCM and CLSM results showed that CLM displayed much higher cellular uptake efficiency and anti-tumor activities than NCLM and free DOX. CLM and NCLM could be internalized by energy-dependent endocytosis mechanism due to similar surface properties. Overall, this dual-stimuli triggered micelle system provided a promising tumor-responsive platform for cancer therapy.

Oral delivery of human growth hormone: Preparation, characterization, and pharmacokinetics

Daily subcutaneous injection of human growth hormone has been used for the treatment of growth hormone deficiency and growth failure but has led to poor patient compliance and renal toxicity. Thus, it is crucial to develop favorable growth hormone delivery systems to improve patient compliance. In the present study, to increase the oral bioavailability of growth hormone and improve patient compliance, enteric-coated capsules filled with monomethoxyl poly(ethylene glycol)-b-poly(L-lactide-co-glycolide) nanoparticles were prepared to facilitate oral growth hormone delivery. The nanoparticles were less than 100 nm in size, exhibited narrow polydispersity indices < 0.3, and showed a zeta potential of −4.87 mV. The highest efficiency of growth hormone encapsulation achieved in this study was nearly 70%. An in vitro release experiment showed that adequate amounts of growth hormone were retained under simulated gastric conditions and significant amounts of growth hormone were released under simulated intestinal conditions. The bioavailability of encapsulated growth hormone relative to subcutaneously injected growth hormone in Sprague-Dawley rats was 11.06%. Thus, the use of poly(ethylene glycol)-b-poly(L-lactide-co-glycolide) nanoparticles yielded promising results, and these agents should be investigated further regarding their potential as an oral growth hormone delivery system in the future.

Tumor-targeted polymeric nanostructured lipid carriers with precise ratiometric control over dual-drug loading for combination therapy in non-small-cell lung cancer

Gemcitabine (GEM) and paclitaxel (PTX) are effective combination anticancer agents against non-small-cell lung cancer (NSCLC). At the present time, a main challenge of combination treatment is the precision of control that will maximize the combined effects. Here, we report a novel method to load GEM (hydrophilic) and PTX (hydrophobic) into simplex tumor-targeted nanostructured lipid carriers (NLCs) for accurate control of the ratio of the two drugs. We covalently preconjugated the dual drugs through a hydrolyzable ester linker to form drug conjugates. N-acetyl-d-glucosamine (NAG) is a glucose receptor-targeting ligand. We added NAG to the formation of NAG-NLCs. In general, synthesis of poly(6-O-methacryloyl-d-galactopyranose)–GEM/PTX (PMAGP-GEM/PTX) conjugates was demonstrated, and NAG-NLCs were prepared using emulsification and solvent evaporation. NAG-NLCs displayed sphericity with an average diameter of 120.3±1.3 nm, a low polydispersity index of 0.233±0.04, and accurate ratiometric control over the two drugs. A cytotoxicity assay showed that the NAG-NLCs had better antitumor activity on NSCLC cells than normal cells. There was an optimal ratio of the two drugs, exhibiting the best cytotoxicity and combinatorial effects among all the formulations we tested. In comparison with both the free-drug combinations and separately nanopackaged drug conjugates, PMAGP-GEM/PTX NAG-NLCs (3:1) exhibited superior synergism. Flow cytometry and confocal laser scanning microscopy showed that NAG-NLCs exhibited higher uptake efficiency in A549 cells via glucose receptor-mediated endocytosis. This combinatorial delivery system settles problems with ratiometric coloading of hydrophilic and hydrophobic drugs for tumor-targeted combination therapy to achieve maximal anticancer efficacy in NSCLC.

Formulation Optimization and In-vitro and In-vivo Evaluation of Lornoxicam Ethosomal Gels with Penetration Enhancers

BACKGROUND Ethosomes, a novel type of percutaneous drug delivery carrier with a lipid bilayer structure, penetrate the skin barrier due to their deformability and malleability, and presence of ethanol that fluidizes lipids in the skin. In order to further enhance the delivery of drugs through the skin, penetration enhancers are widely used. OBJECTIVE The objective of this work was to develop an optimized formulation of lornoxicam ethosomal gels, investigate skin permeability with the addition of penetration enhancers, and evaluate the invivo pharmacodynamics of these formulations. METHODS Lornoxicam ethosomes were prepared by the ethanol injection method and optimized using the orthogonal design method. Lornoxicam ethosomal gels with enhancers were prepared and optimized using in-vitro transdermal delivery experiments. Experiments on lornoxicam ethosomal gels containing various enhancers such as azone, menthol, lauryl alcohol, and oleic acid were conducted using vertical Franz diffusion cells to measure the percutaneous permeability of the different formulations. Furthermore, the in-vivo analgesic effects of the optimized lornoxicam ethosomal gels were examined using the hot-plate and acetic acid-induced writhing tests. Anti-inflammatory activity was investigated using the dimethylbenzene-induced mouse ear swelling method. RESULTS The results showed that compared to other formulations, the optimized lornoxicam ethosomal gels with 5 % menthol significantly increased transdermal penetration. Meanwhile, the optimized lornoxicam ethosomal gels showed remarkably anti-nociceptive and anti-inflammatory activity compared with the plain lornoxicam gels. CONCLUSION These results suggest that the optimized ethosomal gel formulated in this study is a promising lornoxicam carrier in transdermal delivery systems to enhance anti-nociceptive and antiinflammatory efficiency.