Branched polyethylenimine-assisted boronic acid functionalized magnetic nanoparticles for highly efficient capture of lincomycin and clindamycin.

As lincosamide antibiotics, lincomycin and clindamycin are widely used in the drug manufacturing industry for the health of human beings and animals. Thus, the quantitative detection of them in real samples is of great significance. Due to the presence of complex interfering components in actual samples, the separation and enrichment of lincomycin and clindamycin prior to analysis are key. Therefore, it is necessary to develop a non-complex, cost-effective enrichment method for them. A five- or six-membered boronic cyclic ester is formed through boronate affinity materials binding a cis-diol-containing compound in aqueous media, which is a reversible reaction. However, low binding capacity and affinity, and high binding pH of boronate affinity materials are key concerns. In this study, polyethylenimine-assisted 3-fluoro-4-formylphenylboronic acid functionalized magnetic nanoparticles were developed to capture efficiently cis-diol-containing lincomycin and clindamycin under neutral conditions. Thereinto, polyethylenimine (PEI) was applied as a scaffold to amplify the number of boronic acid moieties. And 3-fluoro-4-formylphenylboronic acid was used as an affinity ligand due to its excellent water solubility and low pKa value toward lincomycin and clindamycin. The results indicated that the prepared branched boronic acid-functionalized MNPs provided high binding capacity and fast binding kinetics under neutral conditions. Furthermore, the obtained MNPs exhibited relatively high binding affinity (Kd ≈ 10-4 M) and low binding pH (pH ≥ 6.0).

Effect of octreotide-polyethylene glycol(100) monostearate modification on the pharmacokinetics and cellular uptake of nanostructured lipid carrier loaded with hydroxycamptothecine.

A new conjugate, octreotide-polyethylene glycol(100) monostearate (OPMS), was developed for the enhancement of targeting delivery of hydroxycamptothecine (HCPT) loaded in nanostructured lipid carrier (NLC). 2 × 10(-3) and 5 × 10(-3) mmol of OPMS were respectively used to modify NLC so that the targeted nanocarriers with low and high ligand density were obtained. For comparison, the pegylated NLCs without octreotide were prepared by adding equal molar amounts of polyethylene glycol(100) monostearate (PGMS). The relation between the modification levels and properties of various NLCs were studied in vivo and in vitro. At a high modification level, a slower release rate of HCPT and the more stable nanocarriers was achieved. At the same time, the fixed aqueous layer thickness (FALT) and average surface density of PEG chains (SD(PEG)) was increased, but the distance (D) between two neighboring PEG grafting sites became narrower. The in vivo pharmacokinetic study in healthy rat indicated that the modified NLCs had a longer circulation than NLC (P < 0.05) due to pegylation effect and OPMS modified NLCs had larger MRT and AUC(0-t) than that of PGMS modified NLCs at the same modification level. Furthermore, the florescence microscopy observation also showed the targeting effect of octreotide modification on somatostatin receptors (SSTRs) of tumor cell (SMMC-7721). The uptake of SMMC-7721 was much more than that of normal liver cell (L02) for OPMS modified NLC, and the highest uptake was observed for 5 × 10(-3) mmol of OPMS modified one. No obvious difference was found among the L02 uptake of OPMS modified NLCs and NLC, but their uptake was higher than that of PGMS modified NLCs. All the results indicated that the OPMS highly modified NLCs would improve the effect of antitumor therapy by inhibiting the degradation, evading RES and enhancing the drug uptake of tumor cells.

Preparation of a cationic nanoemulsome for intratumoral drug delivery and its enhancing effect on cellular uptake in vitro.

To develop an appropriate carrier for intratumoral drug delivery, cetyltrimethylammonium bromide (CTAB) modified nanoemulsome (CTAB-NES) was designed and prepared by solvent evaporation method. Coumarin-6 was chosen as the fluorescent probe and the conventional nanoemulsome (NES) without CTAB modification served as a control. The results demonstrated that CTAB-NES had a smaller particle size of 71.9 +/- 4.32 nm, considerate positive zeta potential of +48.7 +/- 0.2 mV, preferably entrapment efficiency of 97.483 +/- 0.693% and the release of coumarin-6 in 24 h was little. The in vitro cytotoxicity of CTAB-NES to the CHO cells and MCF-7 cells increased consistently with concentrations and was higher than that of NES, especially to the cancer cells. Both the fluorescence microscopy images and HPLC assay verified that the cellular uptake of CTAB-NES in MCF-7 cells was much higher than that of NES, and the uptake was time-, concentration- and temperature- dependent. The uptake mechanism results demonstrated that the internalization of CTAB-NES and NES involved clathrin- and caveolae-mediated endocytosis while macropinocytosis only influenced the uptake of CTAB-NES in MCF-7 cells for CTAB could mediate adsorptive pinocytosis. Thus, CTAB-NES with high positive charge and good intracellular uptake ability could be a promising drug carrier for intratumoral drug delivery.

Berberine-Loaded Thiolated Pluronic F127 Polymeric Micelles for Improving Skin Permeation and Retention.

BACKGROUND: Challenges associated with local antibacterial and anti-inflammatory drugs include low penetration and retention of drugs at the expected action site. Additionally, improving these challenges allows for the prevention of side effects that are caused by drug absorption into the systemic circulation and helps to safely treat local skin diseases. METHODS: In the current study, we successfully prepared a thiolated pluronic F127 polymer micelles (BTFM), which binds to keratin through a disulphide bond, to produce skin retention. In addition, the small particle size of polymer micelles promotes the penetration of carriers into the skin. The current study was divided into two experiments: an in vitro experiment; an in vivo experiment that involved the penetration of the micelle-loaded drugs into the skin of rats, the skin irritation test and the anti-inflammatory activity of the drug-loaded micelles on dimethyl benzene-induced ear edema in mice. RESULTS: Results from our in vitro transdermal experiment revealed that the amount of drug absorbed through the skin was decreased after the drug was loaded in the BTFM. Further, results from the vivo study, which used fluorescence microscopy to identify the location of the BTFM after penetration, revealed that there was strong fluorescence in the epidermis layer, but there was no strong fluorescence in the deep skin layer. In addition, the BTFM had a very good safety profile with no potentially hazardous skin irritation and transdermal administration of BTFM could significantly suppress ear edema induced by dimethyl benzene. Therefore, these findings indicated that BTFM reduced the amount of drug that entered the systemic circulation. Our results also demonstrated that the BTFM had a certain affinity for keratin. CONCLUSION: Our experimental results suggest that the BTFM may be an effective drug carrier for local skin therapy with good safety profile.

Glucose transporter and folic acid receptor-mediated Pluronic P105 polymeric micelles loaded with doxorubicin for brain tumor treating.

In this study, glucose transporter and folic acid (FA) receptor-mediated Pluronic P105 polymeric micelles loaded with DOX (GF-DOX) were prepared for enhancing the blood-brain barrier (BBB) transportation and improving the drug accumulation in the glioma cells. The pH-triggered DOX release of GF-DOX indicating a comparatively fast drug release at weak acidic condition and stable state of the carrier at physiological environment. The transport of GF-DOX across the in vitro BBB model showed that GF-DOX exhibited higher BBB transportation ability with the transporting ratio of 21.47% in 4 h. The carrier was internalized into C6 glioma cells upon crossing the BBB model for the combined effect of the brain targeting by transportation of glucose transporter and active tumor cell targeting by FA receptor-mediated endocytosis. Moreover, minimized weight changes and high suppression ratio of tumor growth were observed after intravenous injection of GF-DOX. In conclusion, the glucose transporter and FA dual-targeting micelles would provide a safe and effective strategy for new modalities to treat brain tumor.

Octreotide-mediated tumor cell uptake and intracellular pH-responsive drug delivery of the self-assembly supramolecular nanocarrier.

In this study, DOX-loaded supramolecular nanocarrier (DLSC) was assembled by using two new amphiphilic polymers, octreotide-polyethylene glycol monostearate (OPMS) and N-octyl-N-succinyl O-carboxymethyl chitosan (OSCC). The characteristics of the DLSC were investigated. The results indicated that the significant pH-triggered release in vitro. The cellular uptake of DLSC was much higher than that of DOX-loaded OSCC micelles (DLOM) in the SMMC-7721 (somatostatin receptor (SSTR) over-expressed cell) cells, which suggested the SSTR-mediated properties. A considerable amount of drug entered the nucleus due to the pH-triggered deformation of the supramolecular structure and rapid release of drug in acidic endosomes of tumor cells. The killing efficacy was much higher than that of DLOM in the SMMC-7721. In S180 sarcoma-bearing KM mice, the biodistribution and therapeutic activity were studied. DLSC showed extended circulation time in plasma, decreasing drug concentrations in the heart and accumulating drug concentrations in the pancreas and tumor. In addition, minimized weight changes and cardiac toxicity, high suppression ratio of tumor growth and longer survival time were observed after intravenous injection of DLSC. The studies suggested that the supramolecular nanocarrier constructed of different designated polymers with multiple functions would be one of the most effective approaches for active targeting drug delivery.

Effect of octreotide surface density on receptor-mediated endocytosis in vitro and anticancer efficacy of modified nanocarrier in vivo after optimization.

The objective of the present work was to investigate the optimum density of octreotide on the surface of nanostructured lipid carriers (NLC) loaded with hydroxycamptothencine (HCPT) to enhance receptor-mediated endocytosis and tumor targeting selectivity. Different amounts of octreotide-polyethylene glycol (100) monostearate (OPMS), a ligand for somatostatin receptors (SSTRs), were coupled into NLC. In vitro evaluation of OPMS modified NLCs (O-NLCs) was done by studying the physicochemical properties, drug release, cellular uptake and cytotoxicity. Whereas in vivo evaluation was done by studying the tissue distribution in S180 tumor-bearing mice through ex vivo fluorescence imaging and HCPT quantitative study. The results showed that O-NLCs with an average size of ∼100 nm possessed obvious sustained release. When OPMS was used in the amount of 5 µmol (O5-NLC) highest cellular uptake, cytotoxicity in SMMC-7721 cell line and remarkable accumulation in S180 tumor were observed. The treatments of O5-NLC brought about significant tumor inhibition and prolonged the median survival time as compared with HCPT, unmodified NLC and the pegylated NLC (P5-NLC) groups. It appears that to achieve a more rational approach of receptor mediated tumor targeted drug delivery system the surface density of the targeting moiety on the surface of nanocarriers should be considered.

Octreotide-modified and pH-triggering polymeric micelles loaded with doxorubicin for tumor targeting delivery.

A multifunctional mixed micelle was assembled for drug targeting delivery by combining two newly synthesized amphiphilic polymers, which were octreotide-polyethylene glycol-monostearate (OPMS) and N-octyl-N-succinyl-O-carboxymethyl chitosan (OSCC), respectively. The mixed micelle was designed to be characterized with long circulation, somatostatin receptors (SSTR)-mediated endocytosis and pH sensitivity. A series of assembling proportions of OPMS and OSCC was tested to reveal the effect of compositions on the functions. The particle size, zeta potential, drug loading and critical micelle concentration were examined. The dialysis test indicated a pH-triggering release behavior of the doxorubicin-loaded mixed micelle (DLMM), and faster release in acidic media (pH 4.0-6.0) in response to the protonation of carboxyl group. In addition, the PEG segments could efficiently protect the mixed micelle from plasma protein adsorption in vitro, and the DLMM composed of 20% OPMS and 80% OSCC provided the longest residence time after intravenous injection in rats in vivo. Due to SSTR mediated endocytosis, the significantly higher uptake of DLMM was observed in the tumor cells (SMMC-7721), compared with that in the normal cells (CHO) without SSTR expression. All the results suggested that the mixed micelle with multifunctional characteristics could be used as an effective approach for tumor treatment.