Nowadays, there are more and more researches on characters and applications of polycaprolactone (PCL). This paper reviews the researches of polycaprolactone, including its synthesis, physical and chemical properties, biodegradation, absorption properties, and its applications in clinical use and drug delivery systems. PCL can be from open ring polymerizaion. It is a kind of semi-crystalline polymer, and has good flexibility. The degradation reaction of PCL is hydrolysis. PCL is not cumulated in the body, and can be totally excreted. It can be used as suture, material for fixation of bone fracture, vector of drug, etc. PCL is widely used in medical area because of its safety, low toxicity, biodegradability.
Biodegradation, Environmental ; Drug Carriers ; Polyesters ; chemical synthesis ; chemistry ; metabolism ; Sutures

Pancreatic cancer (PC) is a malignant tumor of the digestive tract with poor patient prognosis. The PC incidence is still increasing with a 5-year survival rate of only 10%. At present, surgical resection is the most effective method to treat PC, however, 80% of the patients missed the best time for surgery after they have been diagnosed as PC. Chemotherapy is one of the main treating methods but PC is insensitive to chemotherapy, prone to drug resistance, and is accompanied by many side effects which are related to a lack of specific target. Exosomes are nanoscale vesicles secreted by almost all cell types and can carry various bioactive substances which mediate cell communication and material transport. They are characterized by a low immunogenicity, low cytotoxicity, high penetration potential and homing capacity, and possess the potential of being used as advanced drug carriers. Therefore, it is a hot research topic to use drug-loaded exosomes for tumor therapy. They may alleviate chemotherapy resistance, reduce side effects, and enhance the curative effect. In recent years, exosome drug carriers have achieved considerable results in PC chemotherapy studies.
Humans ; Exosomes/metabolism* ; Drug Carriers/metabolism* ; Pancreatic Neoplasms/diagnosis* ; Antineoplastic Agents/therapeutic use*

Animals ; Drug Carriers ; Drug Delivery Systems ; Humans ; Kidney Tubules, Proximal ; cytology ; metabolism ; Maleates ; metabolism ; Molecular Weight ; Oligodeoxyribonucleotides, Antisense ; metabolism ; Polyvinyls ; metabolism ; Prodrugs ; metabolism ; Proteins ; metabolism

OBJECTIVETo construct multifunctonal nano-delivery system crossing the blood brain barrier (BBB).

METHODSThe magnetic nanoparticles were preprared with O-carboxylmethylated chitosan (O-CMC) and conjugated with a peptide sequence from the human immunodeficiency virus 1-tat protein and transferrin (Tf), and anti-tumor drug methotrexate (MTX), and thus constructed a O-CMC magnetic nanoparticles carrier system conjugating with Tat and Tf (O-MNPs-Tat-Tf) that combines multiple functions including crossing BBB, magnetism, receptor-mediated dual targets and anti-tumor capabilities. The appearance, diameter, and magnetism of MTX-O-MNPs-Tat-Tf carrier system were characterized with transmission electronic microscopy, atomic force microscopy and vibrating samples magnetometer. The cytotoxicity of MTX-loaded O-MNPs-Tat-Tf was investigated with C6 glioma cells. The ability of O-MNPs-Tat-Tf crossing BBB was investigated in rats by single photon emission computed tomography.

RESULTSThe mean particle diameter was 75 nm, along with good anti-tumor property. The multi-functioned carrier system successfully crossed the BBB in rat.

CONCLUSIONThe establishment of MTX-O-MNPs-Tat-Tf carrier model implies a promising future for its application in therapy of cerebral diseases.

Blood-Brain Barrier ; drug effects ; metabolism ; Chitosan ; analogs & derivatives ; chemistry ; Drug Carriers ; Drug Delivery Systems ; Humans ; Magnetics ; Nanoparticles ; Transferrin

The ischemic heart disease has been endangering human health seriously. Although there are many kinds of anti-ischemic drugs, most of them are lacking in tissue specificity, which together with a remarkably reduced blood circulation in the ischemic zone often lead to a quite low drug distribution in the targets. Myocardial ischemia can cause a lot of pathophysiological changes, such as the enhanced permeability of the endothelial cell membrane, the up-regulated expression of various cell adhesion molecules on endothelium, the exposure of intracellular antigenic components, the decrease of pH within the ischemic zone, and so on. To date, some of these changes have been exploited with limited success to gain the passive, active and physicochemical targeting of diagnostic or therapeutic drugs to myocardial ischemic regions. However, more effective delivery strategies are still eagerly needed. Here, we reviewed and discussed the potential targeting-delivery mechanisms and strategies, used or may be used in the future, for myocardial ischemic regions.
Animals ; Antibodies, Monoclonal ; immunology ; Capillary Permeability ; Drug Carriers ; Drug Delivery Systems ; methods ; Genetic Therapy ; Humans ; Liposomes ; chemistry ; metabolism ; Myocardial Ischemia ; therapy ; Myocardium ; metabolism ; pathology ; Polyethylene Glycols ; metabolism ; Ultrasonics

Liposomes can be cleared by the reticuloendothelial system (RES) when it is in the blood circulation in the body. And they can accumulate in the organs rich in RES in the body by passive targeting. Targeting of the liposomes is an important factor for its use as a drug carrier, and particle size as well as surface charge are important for its in vivo targeting. In this paper, studies on the influences of particle size and surface charge of the liposomes on cell binding and phagocytosis mechanism were reviewed. A comprehensive review on passive targeting effect of the particle size and surface charge of liposomes on blood, liver, spleen as well as tumor tissue was made. At last, an outlook for future research directions was made.
Animals ; Drug Carriers ; chemistry ; Drug Delivery Systems ; Humans ; Liposomes ; chemistry ; pharmacokinetics ; Mononuclear Phagocyte System ; metabolism ; Neoplasms ; metabolism ; Particle Size ; Phagocytosis ; Pinocytosis ; Surface Properties ; Tissue Distribution

Targeted drug delivery can significantly increase the concentration of the drug in treatment site, and decrease the dosage of drugs, cost of treatment and the drug's adverse effects on the body. So targeted drug delivery is the hotspot of recent studies. This paper reviews the development of targeted drug delivery research in recent years, including three areas: passive targeting, active targeting, and physical and chemical targeting.
Animals ; Antibodies ; metabolism ; Drug Carriers ; Drug Delivery Systems ; methods ; trends ; Emulsions ; Humans ; Liposomes ; Magnetics ; Microspheres ; Nanoparticles ; Pharmaceutical Preparations ; administration & dosage ; Photosensitizing Agents ; pharmacology ; Prodrugs ; Receptors, Cell Surface ; metabolism

AIMTo investigate factors affecting the properties of antisense oligodeoxy nucleotides (ASON)-liposomes complex and their cellular uptake.

METHODSThree types of blank liposomes were prepared by reverse-phase evaporation vesicles, and the complex were obtained through physical absorption. The light microscope was used to observe morphology characteristics of the complex. Drug loading capacity was analyzed by agarose gel electrophoresis. The transfected cell percentage and means fluorescence intensity were determined by flow cytometric analysis using M3 myeloma cell as a model.

RESULTSThe neutral liposome showed no aggregation while the cationic liposomes appeared some different extent aggregation in different medium when associated antisense oligodeoxynucleotides. The drug loading capacity depended on the ratio of +/- and the cationic charge density on the lipid membrane. The two kinds of cationic liposomes appeared different principles of loading ASON. As far as cellular uptake, The neutral liposomes showed no improvement of cellular uptake of ASON. However, the cationic liposomes were shown to enhance the cellular uptake of ASON if the appropriate +/- charge ratio was used. The optimal cellular uptake was achieved when +/- charge ratio was at 0.5:1 and 1:1 for SA-I liposome and SA-II liposomes, respectively.

CONCLUSIONThe cationic liposomes improved the loading capacity and cell uptake of antisense oligodeoxynucleotides, which was determined by +/- charge ratio and charge density.

Amines ; metabolism ; Biological Transport ; Drug Carriers ; Drug Delivery Systems ; Humans ; Liposomes ; pharmacokinetics ; Multiple Myeloma ; Oligodeoxyribonucleotides, Antisense ; administration & dosage ; pharmacokinetics ; Random Allocation ; Tumor Cells, Cultured ; metabolism

OBJECTIVETo investigate the absorption enhancen effect of borneol/mentholum eutectic mixture (BO/ME) on nasal-brain delivery of neurotoxin loaded nanoparticles.

METHODUsing microdialysis sampling technique in awake freely-moving rats, the counter per minute (cpm) of dialysates in right PAG of NT-loaded nanoparticles with the BO/ME (BO/ME-NT-NP), radiolabeled with sodium 125I-Iodide, were measured in a gamma-counter for radioactivity. After converting cpm into corresponding concentrations of NT byin vivorecovery of microdialysis probes, the pharmacokinetic parameters were calculated.

RESULTThe BO/ME-NT-NP could be absorbed into the brain, much better to NT-NP and the nanoparticles with borneol or menthdlum only, and the pharmacokinetics accorded with the two-compartment model. The parameters tmax, cmax, AUC, t 1/2(beta) were 0.68 h, 27.32 ng x mL(-1), 132.68 ng x h x mL(-1), 3.1076 h.

CONCLUSIONWith adding BO/ME as absorption enhancer, NT could be significantly increased in the brain with the help of nanopartilces as carriers, and the time to maximal concentration was short, the elimination process was prolonged.

Absorption ; drug effects ; Animals ; Bornanes ; chemistry ; pharmacology ; Brain ; metabolism ; Drug Carriers ; pharmacokinetics ; Male ; Menthol ; chemistry ; pharmacology ; Microdialysis ; Nanoparticles ; Nasal Cavity ; metabolism ; Neurotoxins ; administration & dosage ; pharmacokinetics ; Rats

OBJECTIVETo investigate various methods for constructing soybean lecithin (SL)-based vesicles and evaluate the permeation-enhancing effect of SL-based vesicles on the penetration of insulin through buccal mucosa.

METHODSThe ultrasonic method, high speed shear method and high pressure homogenization method were respectively used to prepare the SL-based vesicles, and the particle size of the vesicles was measured with photon correlation spectrometry (PCS). The penetration rate of insulin through porcine buccal mucosa was investigated with the Valia-Chien diffusion cells.

RESULTSThe average particle sizes of 3 formulations of SL-based vesicles were 97.39, 85.60, and 100.60 nm when prepared by ultrasonic method, and were 58.7, 88.7, and 91.9 nm when prepared by high pressure homogenization method. Both vesicles presented good stability. However, the SL-based vesicles prepared by high speed shear method had larger average diameters and were found to be unstable. Transmission electron microscopy showed that SL-based vesicles had a spherical shape and the result accorded with PCS. The permeation flux of insulin of formulation 1 and control solution were 0.0024 and 0.0008 IU x ml(-1) x min(-1), respectively. The accumulative amount of formulation 1 at 180 min was (0.436 +/- 0.010 ) IU x ml(-1), which was 1.46 times higher than the control solution.

CONCLUSIONSThe SL-based vesicles obtained using high pressure homogenization method are characterized by small particle size, narrow distribution, good stability, and powerful permeation-enhancing effect, which enables them to be good carriers for the buccal delivery of insulin.

Absorption ; Administration, Topical ; Chemistry, Pharmaceutical ; Drug Carriers ; administration & dosage ; chemical synthesis ; pharmacokinetics ; Drug Delivery Systems ; methods ; Insulin ; metabolism ; Mouth Mucosa ; metabolism ; Nanotechnology ; methods ; Phosphatidylcholines ; pharmacokinetics ; Soybeans ; chemistry