Folic acid-modified phospholipid-encapsulated paclitaxel nanocrystals for preoperative chemotherapy of gastric cancer / 药学学报

This paper aims to develop folic acid-modified paclitaxel nanocrystals (PTX NC@FA) with good stability, high drug loading and tumor cell targeting for endoscopic injection for preoperative local chemotherapy of gastric cancer. PTX NC@FA was prepared by the "bottom-up" followed by ultrasonic to study its morphology, particle size, ζ-potential, drug loading, folic acid-modified phospholipid (FA-DSPE-PEG2000) content, crystalline characteristics, stability, in vitro release, cytotoxicity against human gastric cancer cell line SGC-7901, and anti-tumor effect in two different tumor sizes (tumor volume 100 mm3 or 300 mm3) after single peri-tumor injection in a murine subcutaneous SGC-7901 tumor model. Animal experiments were approved by the Experimental Animal Ethics Committee of the School of Pharmacy, Fudan University. The resulting PTX NC@FA was of short rod-like shape, average particle size 175.3 ± 2.5 nm (PDI 0.17 ± 0.02), ζ- potential -2.5 ± 0.2 mV, PTX loading (28.23 ± 0.74) % (w/w) and FA-DSPE-PEG2000 content (4.40 ± 0.60) % (w/w). The size of the PTX NC@FA remained unchanged for 4 days in phosphate buffer with or without serum. Cellular growth inhibition effect on SGC-7901 showed the superiority of PTX NC@FA over nanocrystals without FA modification. PTX NC@FA inhibited tumor growth more efficiently than both nanocrystals without FA modification and commercially available paclitaxel injection (Taxol) 12 days after peri-tumor injection. For model tumor with the volume of 100 mm3, tumors of all animals in the PTX NC@FA group disappeared completely. For model tumor with the volume of 300 mm3, tumors of 3 animals in the PTX NC@FA group completely disappeared and tumors of the rest 4 animals also became significantly smaller with a tumor volume inhibition rate of 90%. PTX NC@FA showed good potential for preoperative chemotherapy of increase the chances of function preserving gastrectomy and improve the quality of life of patients.

The dilemma and breakthrough of oral administration of insulin / 药学学报

Diabetes is characterized by hyperglycemia, resulting from insulin deficiency or resistance, or both. Insulin plays an irreplaceable role in the treatment of diabetes. Subcutaneous injection is the main route of insulin administration, but usually leads to poor compliance and many side effects. Oral insulin is safer and more convenient, which has always been the Holy Grail for people to explore. After oral administration, insulin is absorbed into the hepatic portal vein and transported to the liver, which can activate the normal physiological functions and reduce the risk of hypoglycemia, insulin resistance, and improve patient compliance. However, the gastrointestinal tract has multiple absorption barriers such as chemical barrier, enzyme barrier, and permeation barrier. Due to the physical and chemical properties of insulin, it is difficult to achieve desired oral bioavailability. This article reviews the recent attempts and progress in the field of oral administration of insulin driven by innovative drug delivery technologies and biomaterials, including structural modification, enzyme inhibitors, absorption enhancers, various nanoparticles, liposomes, microspheres, and even microorganisms. Some clinical researches on oral insulin are also introduced.

Gene therapy and delivery strategies for ocular diseases / 药学学报

Gene therapy has obvious advantages in the treatment of ocular diseases due to the unique structure of the eye. In recent years, there are more and more therapeutic gene-based drugs for ophthalmic application in clinical trials. Most of the delivery vectors are adeno-associated virus and administered via intraocular injection, which has potential risks. Traditional remedies, such as topical instillationor systemic administration, have limited therapeutic effects on the diseases in the posterior segment of the eye, where the chemical drugs are hard to reach. This makes the research of new strategies for gene drug delivery extremely urgent. For better understanding of the latest hot topics of ocular gene therapy, this article is prepared to introduce application of gene therapy to the typical ocular diseases and the corresponding gene-based medicines. The absorption routes for gene delivery into eyes and existing barriers are summarized. Finally, the gene delivery strategies are highlighted. The clinical application of ocular gene therapy will be boosted by overcoming the absorbing barriers and reducing the potential pitfalls.

Application of activatable cell-penetrating peptide in the field of tumor therapy / 药学学报

Cell-penetrating peptide (CPP) is a kind of small molecular peptide which can pass through a variety of cell membranes. It can carry bioactive macromolecules into cells. Due to lacking of tissue-selecting and targeting behavior, the application of CPP in the field of tumor treatment is limited. Activatable cell- penetrating peptide (ACPP) has brought the dawn to the application of CPP. This review mainly introduces the applications of ACPP in the targeting antitumor drug delivery which was designed based on the differences between tumor microenvironment and normal tissues as well as the exogenous physical stimulation.

Modification by wheat germ agglutinin delays the ocular elimination of liposome / 药学学报

The purpose of this study is to explore the feasibility of wheat germ agglutinin (WGA) modified liposome as a vehicle for ophthalmic administration. Liposome loaded with 5-carboxyfluorescein (FAM) was prepared by lipid film hydration method. WGA was thiolated and then conjugated to the surface of the liposome via polyethylene glycol linker to constitute the WGA-modified and FAM-loaded liposome (WGA-LS/FAM). The amount of thiol groups on each WGA molecule was determined, and the bioactivity of WGA was estimated after it was modified to the surface of liposome. The physical and chemical features of the WGA-modified liposome were characterized and the ocular bioadhesive performance was evaluated in rats. The result showed that each thiolated WGA molecule was conjugated with 1.32 thiol groups. WGA-LS/FAM had a mean size of (97.40 +/- 1.39) nm, with a polydispersity index of 0.23 +/- 0.01. The entrapment efficacy of FAM was about (2.95 +/- 0.21)%, and only 4% of FAM leaked out of the liposome in 24 h. Erythrocyte agglutination test indicated that after modification WGA preserved the binding activity to glycoprotein. The in vivo ocular elimination of WGA-LS/FAM fitted first-order kinetics, and the elimination rate was significantly slower than that of the unmodified liposome, demonstrating WGA-modified liposome is bioadhesive and suitable for ophthalmic administration.

Poly(arginine)8 enhanced intestinal absorption of insulin-loaded nanoparticles / 药学学报

The purpose of this study is to investigate the feasibility of poly(arginine)8 (R8) modified poly(lactic-co-glycolic acid) (PLGA) nanoparticles as a carrier for the oral delivery of insulin. Insulin-loaded PLGA nanoparticle (INS-NP) was prepared by a double emulsion-solvent evaporation method, and R8 was subsequently conjugated to the surface of the INS-NP via polyethylene glycol bridge (R8-INS-NP). The physical and chemical features of the nanoparticles were characterized, and insulin release was determined in vitro. The pharmacokinetics and pharmacodynamics were evaluated by in situ absorption study with the intestinal loop of rats. The blood glucose level was determined by glucose oxidize method and the serum insulin concentration was determined by radioimmunoassay (RIA). The mean diameter of INS-NP was (179.0 +/- 5.2) nm and the polydispersity index was 0.152 +/- 0.042, while the entrapment efficiency was (29.10 +/- 2.59) %. The in vitro release behavior of insulin showed an initial burst effect followed by a stage of slow release. After administrating 10 U x kg(-1) insulin to rats, R8-INS-NPs decreased the plasma glucose level much lower than INS-NPs, meanwhile, D-form R8 substantially enhanced intestinal absorption of insulin much more than L-form R8. Compared to subcutaneous injection, the relative bioavailabilities of insulin were 0.52%, 4.78%, 8.39%, and the pharmacological bioavailabilities were 2.07%, 3.90%, 8.24%, separately. The R8-modified nanoparticles promoted the intestinal absorption of insulin, which might be a potential approach for oral delivery of peptide, protein and even other hydrophilic macromolecules in the future.

Preparation and in vitro targeting of sterically stabilized liposomes modified with chimeric TNT-3 monoclonal antibody / 药学学报

<p><b>AIM</b>To prepare sterically stabilized liposomes modified with chimeric TNT-3 monoclonal antibody (chTNT-3) and investigate their immunoreactivity and in vitro targeting.</p><p><b>METHODS</b>An end-group functionalized polyethylene glycol-lipid derivative (pyridylthiopropionoylamino-polyethylene glycol-hydrogenated soy phosphatidylethanolamine, PDP-PEG-HSPE) was synthesized and incorporated to sterically stabilized liposomes. After mild thiolysis of the PDP groups by dithiothreitol, liposomes were covalently linked with maleimide-derivatized chTNT-3 and formed sterically stabilized immunoliposomes. Coupling efficiency, antibody density, size distribution, immunoreactivity of chTNT-3-modified sterically stabilized liposomes (chTNT-3-SLs) and specific binding properties of the chTNT-3-SLs to fixed Raji cells were determined, separately.</p><p><b>RESULTS</b>Higher initial Ab/PDP-PEG-HSPE molar ratios resulted in higher antibody density on the surface of liposomes but lower coupling efficiency. The optimal coupling efficiency of 71% was obtained while antibody density in liposome was 106 microg antibody/micromol phospholipids (as initial antibody/PDP-PEG-HSPE = 1 : 10). The chTNT-3-SLs had a narrow size distribution after extrusion and the mean size of this immunoliposomes was (115 +/- 33) nm. The immunoreactivity of chTNT-3 can be preserved after efficient attachment of maleimide-derivatized chTNT-3 to the surface of liposomes. But calculated per antibody concentration, the immunoreactivity of chTNT-3-SLs would obviously decrease compared to that of chTNT-3 or chTNT-3 derivatives. Significantly higher binding of chTNT-3-SLs to fixed Raji cells directed by chTNT-3 was obtained compared to other preparations in serial dilutions (P < 0.01).</p><p><b>CONCLUSION</b>chTNT-3-SLs prepared by PDP-PEG-HSPE method remained most immunoreactivity of chTNT-3 and was able to bind nuclear antigens in vitro.</p>

Binding characteristics between RGD-containing cyclic peptide and rat hepatic stellate cells: an in vitro study / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the binding characteristics between an artificial Arg-Gly-Asp (RGD)-containing cyclic peptide [cyclo(CGRGDSPK)] and rat hepatic stellate cells (HSC).</p><p><b>METHODS</b>An artificial RGD-containing cyclic peptide was labeled with fluorescein isothiocyanate (FITC). HSCs were isolated by collagenase in situ liver recirculating and purified by density gradient centrifugation from normal rats. The cells were cultured for 5 days of primary culture (quiescent phenotype) or for 7 days of secondary culture (activated phenotype). To access the binding and uptake, HSCs were incubated with FITC-cRGD of different concentrations at 4 degree C or 37 degree C, and then the binding and uptake were investigated by flow cytometry. The location of FITC-cRGD in HSC was investigated by fluorescent microscopy. Kd and maximal binding sites per cell were calculated by radioligand binding assay (RBA) of receptors using 3H-cRGD. In the interim, FITC-cAGA was used as a peptide control devoid of any binding site.</p><p><b>RESULTS</b>The binding between FITC-cRGD and HSC was saturable, time- and dose-dependent and could compete with overdosed unlabeled cRGD. The fluorescence was mainly distributed in cytoplasma, especially near the nuclei. Kd was 7.05 x 10(-9) mol/L and Bmax per cell was nearly 6.79 x 10(5).</p><p><b>CONCLUSIONS</b>The results demonstrate that cRGD are specifically taken up by HSC through a receptor-mediated pathway. The information is useful for understanding the ligand-receptor interaction of HSC. FITC labeled cyclic RGD-peptides meet the standards of special ligands and FITC does not change the binding activation of cyclic RGD-peptides.</p>

Diffusion behaviors of drugs in thermosensitive in situ gels / 药学学报

<p><b>AIM</b>To study the diffusion behaviors of drugs in thermosensitive in situ gels, and provide valuable information for designing such delivery systems.</p><p><b>METHODS</b>A free diffusion model was used to evaluate the effects of concentration, the property of drugs, as well as the gel compositions on the diffusivity of drugs.</p><p><b>RESULTS</b>Drug transport through the aqueous channels of the gel followed Fickian mechanism, and no significant influence on the diffusivity was observed when the drug concentration was lowered from 5% to 0.25%. The diffusion coefficients of propranolol, timolol maleate, and salbutamol sulfate were 0.91, 1.32, and 3.30 x 10(-6) cm2 x s(-1), respectively. The flux of hydrophilic drug was 3.6 fold faster than that of the lipophilic one implied the latter partitioned into the hydrophobic micellar core, and consequently the diffusion was retarded. The diffusivity was decreased with increased poloxamer and sodium hyaluronate concentration, due to the distorted aqueous channels and higher microviscosity.</p><p><b>CONCLUSION</b>The result suggested that sustained release could be achieved for the thermosensitive in situ gel by incorporating lipophilic drug or increasing polymer concentration.</p>

Influence of different doxorubicin-salt aggregates on the leakage of liposomal doxorubicin in vitro and long circulation in vivo / 药学学报

<p><b>AIM</b>To develop liposomes containing doxorubicin with different salts and to investigate their influence on the stability of liposomal doxorubicin in vitro and in vivo.</p><p><b>METHODS</b>Liposomes were prepared by the film method, treated further by extruded through nuclear membrane. The entrapment efficiency was determined by column chromatography. In vitro drug release experiments were carried out with a dialysis bag (Mw cut-off 12000 - 14000). Reverse-phase HPLC was used to study the pharmacokinetics of liposomal doxorubicin.</p><p><b>RESULTS</b>The particle size of liposomes with glycinate buffer, citrate buffer and ammonium sulfate as the inner water phase were (103 +/- 8), (102 +/- 12) and (97 +/- 8) nm. The zeta potential and the encapsulation ratio were (-21.3 +/- 0.5), (-21.7 +/- 0.4), (-20.9 +/- 0.7) mV and 47.8%, 96.7%, 98.6%, respectively. The leaking rate of doxorubicin from liposomes was related to the pH value of the release medium. The leaking rate increased at lowered pH. Pharmacokinetic study showed that the MRT (mean retention time) of liposomes with glycinate buffer, citrate buffer and ammonium sulfate as the inner water phase were 12.13, 23.31 and 29.79 h, respectively.</p><p><b>CONCLUSION</b>Doxorubicin showed different stability in liposomes with different inner water phases, the weaker the acid in the inner water phase, the stabler the liposome.</p>

Spectrophotometry on measuring the size of liposomes / 药学学报

<p><b>AIM</b>To establish a spectrophotometric method for measurement of the sizes of liposomes for evaluating physical stability of liposomes.</p><p><b>METHODS</b>The sterically stabilized liposomes (SLs) were prepared by ethanol injection method and extrusion method. The mean cumulant diameters (D) of the vesicles were determined by electron microscopy and dynamic light scattering. On the basis of Rayleigh-Gans-Debye theory, the absorbance at 436 nm per unit lipid concentration (A436 nm/Cp) was measured as a function of vesicle diameter.</p><p><b>RESULTS</b>log(A436 nm/Cp) was closely related to logD (r2 > or = 0.93, n = 5).</p><p><b>CONCLUSION</b>The absorbance of liposomes reflect their relative sizes and can be used to evaluate physical stability of liposomes.</p>