In this study, the reductive amination method was used to label IR783 on Astragalus polysaccharides(APS) for the first time, which was verified by ultraviolet-visible spectroscopy and infrared spectroscopy. Quantitative analysis methods of APS-IR783 in plasma and various tissue were established using a multifunctional microplate reader. The pharmacokinetics and tissue distribution of APS-IR783 in mice were investigated after a single intravenous injection of 30 mg·kg~(-1) APS-IR783, and pharmacokinetic parameters were calculated using DAS 2.0 software. The results showed that the APS used had a mass fraction of 93.69%, a relative molecular weight of 1.55×10~5, and a polydispersity index(PDI, M_w/M_n) of 1.73, close to a homogeneous polysaccharide. The IR783 labeling yield reached 86.50%, and the content of IR783 in APS-IR783 was 0.72%. After a single intravenous injection of 30 mg·kg~(-1), the pharmacokinetic parameters of APS in mouse plasma were as follows: T_(max) was(0.67±0.26) h; C_(max) was(1 599.29±159.30) mg·L~(-1); T_(1/2α) and T_(1/2β) were(2.29±3.06) h and(0.44±0.05) h, respectively; AUC_(0-t) was(23 398.91±2 907.03) mg·h·L~(-1); AUC_(0-∞) was(27 710.55±3 506.55) mg·h·L~(-1); MRT_(0-∞) was(34.38±12.59) h; CL was 0.001 L·h~(-1)·kg~(-1); V_z was(0.042±0.017) L·kg~(-1). The in vivo biodistribution study demonstrated that the in vivo exposure ratios of APS in different tissue were in the following order: spleen > liver > kidney > lung > heart > small intestine > muscle > large intestine > brain > stomach, where the top five tissue accounted for 87.54% of the total area under the curve(AUC). This study successfully labeled APS with a water-soluble near-infrared fluorescent probe of IR783 for the first time and revealed the pharmacokinetics and tissue distribution of APS in mice. The paper provides detailed in vivo behavior of APS after intravenous injection, which lays the foundation for the development and utilization of APS and related natural medicines.
Animals ; Mice ; Polysaccharides/chemistry* ; Tissue Distribution ; Astragalus Plant/chemistry* ; Male ; Drugs, Chinese Herbal/chemistry* ; Fluorescent Dyes/pharmacokinetics* ; Female

Astragalus polysaccharides was lounded to 4-(2-aminoethylphenol), followed by labeling the APS-Tyr with fluorescein-5-isothiocyanate (FITC) at the secondary amino group. The absorption enhancement effects of low molecular weight chitosan and protamine on astragalus polysaccharides were evaluated via Caco-2 cell culture model. The results show that the fluorecent labeling compound has good stability and high sensitivity. On the other hand low molecular weight chitosan and protamine also can promoted absorption of the astragalus polysaccharides without any cytotoxity, and the absorption increase was more significant with increasing the amount of low molecular weight chitosan and protamine. At the same time, the low molecular weight chitosan has slightly better effect. The transepithelial electric resistance (TEER) of Caco-2 cells show that absorption enhancers could improve its membrane transport permeability by opening tight junctions between cells and increasing the cell membrane fluidity.
Absorption ; Astragalus Plant ; chemistry ; Biological Transport ; Caco-2 Cells ; Fluorescein-5-isothiocyanate ; chemistry ; Fluorescent Dyes ; chemistry ; Humans ; Plant Extracts ; chemistry ; pharmacokinetics ; Polysaccharides ; chemistry ; pharmacokinetics

Blood-brain barrier (BBB) is the major obstacle for drug delivery into the central nervous system (CNS). However, there is no ideal model animal for the study of BBB permeability till now. Currently zebrafish (Danio rerio) has emerged as a powerful model organism for the study of vertebrate biology. In this study, the feasibility of using zebrafish as model animal was investigated for BBB permeability by comparing the results of administration of BBB-penetrating peptide and protein to mouse and zebrafish. The results showed that the BBBs of mouse and zebrafish were similar in molecular permeability. Additionally, zebrafish has advantageous features as a model animal, such as small size, fertile and easy to breed. Therefore, it is suggested that zebrafish may be a favored model for the study of BBB permeability.
Animals ; Blood-Brain Barrier ; metabolism ; Brain ; metabolism ; Female ; Fluorescent Dyes ; pharmacokinetics ; Glycoproteins ; pharmacokinetics ; Green Fluorescent Proteins ; pharmacokinetics ; Male ; Mice ; Models, Animal ; Peptide Fragments ; pharmacokinetics ; Permeability ; Rhodamines ; pharmacokinetics ; Tissue Distribution ; Viral Proteins ; pharmacokinetics ; Zebrafish ; metabolism

The hydroxycamptothecin (HCPT) PEGylated liposomes (HCPT-LP) were modified with RGD cyclopeptide formed the tumor-targeting liposomes (HCPT-RGD-LP). HCPT-LP and HCPT-RGD-LP were injected intravenously with single dose of 5 mg x kg(-1) to rats. The drug concentration in plasma was determined and the pharmacokinetic behaviour was compared. The HCPT distribution in heart, liver, spleen, lung, kidney and plasma of mice was investigated following intravenous administration of HCPT-LP and HCPT injection. The nude mice implanted human hepatoma HepG2 cells were studied by in vivo imaging. The fluorescent probe was DiR and the nude mice were injected with DiR PEGylated liposomes (DiR-LP) and DiR-LP modified with RGD cyclopeptide (DiR-RGD-LP). The results showed that there was no significant difference (P > 0.05) of main pharmacokinetic parameters t1/2beta, CL, V(c), AUC(0-48 h), AUC(0-inifinity), MRT(0-48 h), MRT(0-infinity) between HCPT-RGD-LP and HCPT-LP. HCPT-LP had a remarkably better long-circulating effect than HCPT injection in mice and the concentration of HCPT was highest in liver. The DiR accumulation in tumors of DiR-RGD-LP was higher than that of DiR-LP by the visualized fluorescence of in vivo imaging. It indicated that such PEGylated liposomes modified with RGD cyclopeptide could improve the tumor targeting efficacy.
Animals ; Area Under Curve ; Camptothecin ; administration & dosage ; analogs & derivatives ; chemistry ; pharmacokinetics ; Diagnostic Imaging ; Drug Delivery Systems ; Female ; Fluorescent Dyes ; Hep G2 Cells ; Humans ; Liposomes ; administration & dosage ; chemistry ; pharmacokinetics ; Liver Neoplasms ; diagnosis ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Transplantation ; Oligopeptides ; administration & dosage ; chemistry ; pharmacokinetics ; Polyethylene Glycols ; administration & dosage ; chemistry ; pharmacokinetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Spectroscopy, Near-Infrared ; Tissue Distribution

The real-time in vivo measurement method has been urgently needed in the research of pharmacokinetics. In the present paper a new in vivo detection method based on fluorescence spectroscopy has been proposed and the monitoring system has been built which is used for pharmacokinetics studies in rats. The relationship between fluorescence intensity and concentration was obtained. By detecting the fluorescent dye Cypate in real-time in rats, the properties of the system have been validated by comparing with the fluorescence imaging system in vitro. The results showed that the system could be feasible for: (1) The linear regression equation of Cypate concentration in the range of 0.098-25 microg/ml is y = 73.249x + 130.97 (R2 = 0.9991 and P < 0.001). RSD of high, medium and low concentration is 1.23%, 6.29% and 13.48%, respectively, and the detecting sensitivity is 0.0981 g/ml; (2) The fluorescent dye concentration from the system is consistent (r = 0.9925) with the fluorescence imaging system in vitro. The fluorescent dye metabolism in rats can be well detected. It can be concluded that a new real-time in vivo detecting method in the paper can be used in pharmacokinetics research.
Animals ; Fluorescent Dyes ; pharmacokinetics ; Rats ; Spectrometry, Fluorescence ; methods ; Spectroscopy, Near-Infrared ; methods

AIMThe purpose of this study was to develop a mathematical model to quantitatively describe the passive transport of macromolecules within dental biofilms.

METHODOLOGYFluorescently labeled dextrans with different molecular mass (3 kD, 10 kD, 40 kD, 70 kD, 2000 kD) were used as a series of diffusion probes. Streptococcus mutans, Streptococcus sanguinis, Actinomyces naeslundii and Fusobacterium nucleatum were used as inocula for biofilm formation. The diffusion processes of different probes through the in vitro biofilm were recorded with a confocal laser microscope.

RESULTSMathematical function of biofilm penetration was constructed on the basis of the inverse problem method. Based on this function, not only the relationship between average concentration of steady-state and molecule weights can be analyzed, but also that between penetrative time and molecule weights.

CONCLUSIONThis can be used to predict the effective concentration and the penetrative time of anti-biofilm medicines that can diffuse through oral biofilm. Furthermore, an improved model for large molecule is proposed by considering the exchange time at the upper boundary of the dental biofilm.

Actinomyces ; growth & development ; Algorithms ; Biofilms ; growth & development ; Biological Transport ; Dental Plaque ; microbiology ; Dextrans ; pharmacokinetics ; Diffusion ; Fluorescent Dyes ; pharmacokinetics ; Fusobacterium nucleatum ; growth & development ; Macromolecular Substances ; pharmacokinetics ; Microscopy, Confocal ; Models, Biological ; Molecular Probe Techniques ; Streptococcus mutans ; growth & development ; Streptococcus sanguis ; growth & development

Herein, solid lipid nanoparticles (SLN) were proposed as a new drug delivery system for adefovir dipivoxil (ADV). The octadecylamine-fluorescein isothiocynate (ODA-FITC) was synthesized and used as a fluorescence maker to be incorporated into SLN to investigate the time-dependent cellular uptake of SLN by HepG2.2.15. The SLN of monostearin with ODA-FITC or ADV were prepared by solvent diffusion method in an aqueous system. About 15 wt% drug entrapment efficiency (EE) and 3 wt% drug loading (DL) could be reached in SLN loading ADV. Comparing with free ADV, the inhibitory effects of ADV loaded in SLN on hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and hepatitis B virus (HBV) DNA levels in vitro were significantly enhanced.
Adenine ; administration & dosage ; analogs & derivatives ; pharmacokinetics ; Amines ; Antiviral Agents ; administration & dosage ; pharmacokinetics ; Cell Line ; Drug Delivery Systems ; Fluorescein-5-isothiocyanate ; Fluorescent Dyes ; Glycerides ; Hepatitis B virus ; drug effects ; Humans ; Nanoparticles ; Nanotechnology ; Organophosphonates ; administration & dosage ; pharmacokinetics

A sensitive, rapid method for determining reduced tiopronin concentration in rat plasma has been developed by using a high-performance liquid chromatography (HPLC) technique in conjunction with the derivatizing agent N-(1-pyrenyl) maleimide (NPM). The analytes were separated on a Kromasil C18 column (250 mm x 4.6 mm, 5 microm) using 0.2% glacial acetic acid aqueous solution including 0.015 mol x L(-1) KH2PO4 and acetonitrile (56:44) as a mobile phase at a flow-rate of 0.8 mL x min(-1), and fluorescence detection wavelength were set at lamda(e x) = 340 nm and lamda(e m) = 375 nm, the column temperature was 30 degrees C. The calibration curve was found to be linear over a range of 0.1 - 10.0 microg x mL(-1), the limit of quantitation was 0. 1 mg x L(-1). The coefficients of the variation for the within-run and between-run precisions ranged from 5.3% to 10.8% and 7.0% to 10.8%, respectively. The percentage of absolute recovery ranged from 73.7% to 79.7%. The method was used to determine the concentration of tiopronin in rat plasma after a single intragastric administration of 25 mg x kg(-1) tiopronin to 6 healthy male Wistar rats. The pharmacokinetic process was fitted to a two-compartment model. The method has been successfully applied to the determination of tiopronin in rat plasma.
Animals ; Area Under Curve ; Chromatography, High Pressure Liquid ; methods ; Fluorescent Dyes ; chemistry ; Male ; Maleimides ; chemistry ; Rats ; Rats, Wistar ; Tiopronin ; blood ; pharmacokinetics

OBJECTIVETo investigate uptake and accumulation of gentamicin by cells in the guinea pig inner ear after intratympanic injection using a fluorescent probe--gentamicin-Texas-red conjunction (GTTR).

METHODSAdult guinea pigs (n = 80) were administered a single dose of GTrR to the middle ear cavity through the intact membrane and survived for 12 h, 24 h, 48 h, 3 d, 4 d, 7 d, 14 d and 28 d. The distribution of GTTR in the cochlear and vestibular cells was observed after staining with phalloidin-alexa-488. Texas Red and DMSO were injected into the tympanum as control.

RESULTSDiffuse staining of gentamicin in the labyrinth was observed initially after local drug administration. At later time point the outer hair cells and sensory cells of vestibular organ were staining more densely than the support cells in the inner ear. The peak level of fluorescent density was reached 3 days after local injection. The GTTR was observed in the infracuticular zone.

CONCLUSIONSGTTR was a potential fluorescent probe to investigate the pharmacokinetics and mechanisms of gentamicin accumulation in local application.

Animals ; Anti-Bacterial Agents ; administration & dosage ; pharmacokinetics ; toxicity ; Ear, Inner ; metabolism ; Fluorescent Dyes ; Gentamicins ; administration & dosage ; pharmacokinetics ; toxicity ; Guinea Pigs ; Hair Cells, Auditory ; metabolism

OBJECTIVETo establish an assay method for detecting the migration of transferred apoptotic cells into the recipient using flow cytometry.

METHODSSpleen lymphocytes were isolated and labeled with an intracellular amine dye, carboxyfluorescein diacetate succinimidyl ester (CFSE), to allow discrimination. The labeled cells were induced with dexamethasone to undergo apoptosis and transferred into recipient mice via tail venous transfusion. Flow cytometry and histological examination of different tissues were performed at different time points. The stability of CFSE labeling for apoptotic cells was also tested.

RESULTSThe CFSE-labeled apoptotic cells were highly fluorescent with a positive labeling rate of (98.0+/-1.9)%. The stability of CFSE-labeling was testified, and the CFSE-labeled apoptotic cells entering different tissues at different time points were detected by flow cytometry and verified by histological examination.

CONCLUSIONFlow cytometry using CFSE labeling is reliable, sensitive, precise and convenient for apoptotic cell tracing in vivo and in vitro.

Adoptive Transfer ; methods ; Animals ; Apoptosis ; Dexamethasone ; pharmacology ; Female ; Flow Cytometry ; methods ; Fluoresceins ; chemistry ; pharmacokinetics ; Fluorescent Dyes ; chemistry ; pharmacokinetics ; Lymphocytes ; chemistry ; cytology ; drug effects ; Mice ; Mice, Inbred BALB C ; Reproducibility of Results ; Spleen ; cytology ; Succinimides ; chemistry ; pharmacokinetics