Sustained release donepezil loaded PLGA microspheres for injection:Preparation,in vitro and in vivo study

The purpose of this study was to develop a PLGA microspheres-based donepezil(DP)formulation which was expected to sustain release of DP for one week with high encapsulation efficiency(EE).DP derived from donepezil hydrochloride was encapsulated in PLGA microspheres by the O/W emulsion-solvent evaporation method.The optimized formulation which avoided the crushing of microspheres during the preparation process was characterized in terms of particle size,morphology,drug loading and EE,physical state of DP in the matrix and in vitro and in vivo release behavior.DP microspheres were prepared successfully with average diameter of 30m,drug loading of 15.92±0.31%and EE up to 78.79±2.56%.Scanning electron microscope image showed it has integrated spherical shape with no drug crystal and porous on its surface.Differential scanning calorimetry and X-ray diffraction results suggested DP was in amorphous state or molecularly dispersed in microspheres.The Tg of PLGA was increased with the addition of DP.The release profile in vitro was characterized with slow but continuous release that lasted for about one week and fitted well with first-order model,which suggested the diffusion governing release mechanism.After single-dose administration of DP microspheres via subcutaneous injection in rats,the plasma concentration of DP reached peak concentration at 0.50 d,and then declined gradually,but was still detectable at 15 d.A good correlation between in vitro and in vivo data was obtained.The results suggest the potential use of DP microspheres for treatment of Alzheimer’s disease over long periods.

THE SPECIFIC PHOTODYNAMIC EFFECTS OF MONOCLONAL ANTIBODIES CONJUGATED WITH HEMATOPORPHYRIN DERIVATIVE ON GASTRIC CANCER IN VITRO AND IN VIVO

Murine monoclonal antibody (MoAb) BB4.3, raised against the human gastric cancer cell line BGC823, was puriffied with Protein A-Sepharose CL-4B affinity chromatography and identified as IgG2a. It was then conjugated with a hematoporphyrin derivative (HPD) by using carbodiimide. The qualitative analysis of this conjugate showed that the amount of free HPD was negligible and there were no IgG aggregates among the conjugates. The conjugate retained both the antibody and photochemical activity of HPD.In vitro, the phototoxic effect of this HPD-BB4.3 conjugate on target cells was about 15 times higher than that of free HPD. The quality of selective photocytotoxicity was proven by the greater cytotoxi-city this conjugate showed than that of corresponding normal mouse IgG (NIgG) conjugated with HPD. It showed less cytotoxicity to colon cancer cell line B-80 (negative reaction to MoAb BB4.3) than to BGC825. Moreover, its cytotoxicity to BGC823 cells could be blocked specifically by excess BB4.3 antibody, but not by another MoAb 3G9, which combines with BGC823 at different binding sites from MoAb BB4.3.Nude mice inoculated with 2 × 10- BGC823 cells were given HPD-BB4.3, HPD, HPD-NIgG, HPD plus BB4.3 and PBS, respectively then exposed to light. Four out of six animals treated with the HPD-BB4.3 conjugate remained tumor-free for a long period. Although two developed tumors, there was a significant difference between the HPD-BB4.3-treated group and all the control groups in tumor induction time, tumor growth rate, and survival time (p<0.001). The HPD-BB4.3 conjugate inhibited the growth of established tumors by more than 40% in comparison with control groups (p<0.05).

Effect of temsirolimus on bladder cancer cells in vitro and in vivo

Objective To examine the effects of temsirolimus, an inhibitor of mammalian target of rapamycin,on bladder cancer cell lines T24 and BIU-87 in vitro and in vivo for purpose of evaluating the probability of mTOR targeted therapy for bladder cancer. Methods After

Progress in experimental models to investigate the in vivo and in vitro antidiabetic activity of drugs

Diabetes mellitus is one of the world's most prevalent and complex metabolic disorders,and it is a rapidly growing global public health issue.It is characterized by hyperglycemia,a condition involving a high blood glucose level brought on by deficiencies in insulin secretion,decreased activity of insulin,or both.Prolonged effects of diabetes include cardiovascular problems,retinopathy,neuropathy,nephropathy,and vascular alterations in both macro-and micro-blood vessels.In vivo and in vitro models have always been important for investigating and characterizing disease pathogenesis,identifying targets,and reviewing novel treatment options and medications.Fully understanding these models is crucial for the researchers so this review summarizes the different experimental in vivo and in vitro model options used to study diabetes and its consequences.The most popular in vivo studies involves the small animal models,such as rodent models,chemically induced diabetogens like streptozotocin and alloxan,and the possibility of deleting or overexpressing a specific gene by knockout and transgenic technologies on these animals.Other models include virally induced models,diet/nutrition induced diabetic animals,surgically induced models or pancreatectomy models,and non-obese models.Large animals or non-rodent models like porcine(pig),canine(dog),nonhuman primate,and Zebrafish models are also outlined.The in vitro models discussed are murine and human beta-cell lines and pancreatic islets,human stem cells,and organoid cultures.The other enzymatic in vitro tests to assess diabetes include assay of amylase inhibition and inhibition ofα-glucosidase activity.

In vitro and in vivo correlation for lipid-based formulations: Current status and future perspectives

Lipid-based formulations(LBFs)have demonstrated a great potential in enhancing the oral absorption of poorly water-soluble drugs.However,construction of in vitro and in vivo correlations(IVIVCs)for LBFs is quite challenging,owing to a complex in vivo processing of these formulations.In this paper,we start with a brief introduction on the gastrointestinal digestion of lipid/LBFs and its relation to enhanced oral drug absorption;based on the concept of IVIVCs,the current status of in vitro models to establish IVIVCs for LBFs is reviewed,while future perspectives in this field are discussed.In vitro tests,which facilitate the understanding and prediction of the in vivo performance of solid dosage forms,frequently fail to mimic the in vivo processing of LBFs,leading to inconsistent results.In vitro digestion models,which more closely simulate gastrointestinal physiology,are a more promising option.Despite some successes in IVIVC modeling,the accuracy and consistency of these models are yet to be validated,particularly for human data.A reliable IVIVC model can not only reduce the risk,time,and cost of formulation development but can also contribute to the formulation design and optimization,thus promoting the clinical translation of LBFs.

In vitro and in vivo biocompatibility of Mg–Zn–Ca alloy operative clip

At present,titanium(Ti)and its alloys are most commonly use in hemostasis clip clinical applications.However,the Ti Clip cannot be absorbed in human body and produce artifacts on computed tomography(CT),and induce clinically relevant hypersensitivity in patients.In order to overcome the drawbacks of the non-degradable Ti clips,an Mg-Zn-Ca alloy operative clip was fabricated by combining hot extrusion and blanking processing.In vitro and in vivo biocompatibility of Mg-Zn-Ca alloy operative clip were evaluated by L-929 Cells and SD rat model respectively.It was found that Mg-Zn-Ca alloy exhibited non-cytotoxic to L929 cells.In vivo implantation showed that the newly designed Mg-Zn-Ca clip can successfully ligated carotid artery and no blood leakage occurred post-surgery.During the period of the clip degradation,a small amount of H2 gas formation and no tissue inflammation around the clips were observed.The degradation rate of the clip near the heart ligated the arteries faster than that of clip far away the heart due do the effect of arterial blood.Histological analysis and various blood biochemical parameters in rat serum samples collected at different times after clip implantation showed no tissue inflammation around the clips.

Design and comparative in-vitro and in-vivo evaluation of starch-acrylate graft copolymer based salbutamol sulphate sustained release tablets

The present work deals with the development of controlled release tablets of salbutamol sulphate(SS)using graft copolymers of methyl methacrylate(St-g-PMMA and Ast-g-PMMA)on starch and acetylated starch.Formulations were evaluated for physical characteristics like hardness,friability,drug release,drug content and weight variations,which fulfilled all the official requirements of tablet dosage form.The release rates from formulated matrix tablets were studied at SGF(pH 1.2)followed by SIF(pH 6.8).Drug release from the graft copolymer based tablets was found to be sustained upto the 14 h with>75%drug release.The in-vitro release study showed that the graft copolymer based matrix formulations(F3&F4)exhibited highest correlation value(r2)for higuchi kinetic model and Korsmeyer's model with n values between 0.61 and 0.67 proved that release mechanisms were governed by both diffusion and erosion mechanism.There was no significant difference in the pharmacokinetic parameters(tmax,Cmax,AUC,Ke,and t1/2)of the graft copolymers matrices and HPMC K100M matrix tablets,indicating their comparable sustained release effect.The potential of graft copolymers to sustain the drug release is well supported by in-vivo pharmacokinetic studies and their adequate physicochemical properties make them promising excipients for controlled drug delivery system.

ANTIVIRAL EFFECTS ON MOUSE LEUKEMIA VIRUS REPLICATION BY OLIGODEOXYNUCLEOTIDES IN VITRO AND IN VIVO

Oligodeoxynucleotides (Oligomers) including modified and unmodified, homo-and heterooligomers were tested for their ability to inhibit mouse SRS leukemia virus (SRSV)-induced proliferation of cells, colony formation, syncytium formation and reverse transcriptase (RT) activity in vitro. Phosphorothioate analogs complementary to Mo-MuLV sequences, as well as noncomplementary homooligomers, were found to be active. Unmodified homooligomer (dC14) also showed inhibition of growth of ascitic lymphoma carrying SRS virus. Our study suggests that different classes of oligonucleotides may inhibit SRSV replication with different mechanisms.

IN VITRO AND IN VIVO EVALUATION OF THE SAFETY OF SOME BENINESE PLANTS USED IN TRADITIONAL MEDICINE

About 80%of population in developing countries use traditional remedies in their usual health care and plants used in traditional medicine are an interesting alternative to expensive and hardly available modern medicines,mainly in rural areas.Moreover,they are a promising source of new drugs structurally innovative.Therefore it is important to investigate their biological properties and we focused on5 beninese plants:Byrsocarpus coccineus Schumach.&Thonn(Connaraceae),Carpolobia lutea G.Don(Polygalaceae),

Effects of insulin-like growth factor binding protein 7 on cell cycle and proliferation of gastric cancer in vitro and in vivo

Objective To investigate the effects of insulin-like growth factor binding protein 7(IGFBP7)on the proliferation,cell cycle of gastric cancer cell and the expression of cynlin D1,cyclin-dependent kinase(CDK)4,and to observe the effects of IGFBP7 on the growth of gastric tumor xenografts in nude mice.Methods The MKN-28cell line was interfered by small interfere ribonucleic acid(siRNA)(interfered group),and blank control group,

Preparation and evaluation of sustained-release diltiazem hydrochloride pellets

In this study,diltiazem hydrochloride(DTZ)pellets were prepared successfully by extrusionespheronization method.Then methacrylic acid and ethylcellulose coating formulations were employed to make the DTZ pellets sustained release.The pellets with different coatings were investigated by in vitro dissolution tests.At last,the pellets with the best coating copolymer were subjected to pharmacokinetic studies in beagle dogs.The dissolution profiles of pellets coated with Eudragit
NE30D were similar to Herbesser
,one of the marketed sustained release capsules.In the bioavailability study,the principal pharmacokinetic parameters of self-made pellets and the marketed ones were comparable;the relative bioavailability of DTZ sustained release capsules compared with Herbesser
was 98.5
36.4%.All the data indicated self-made sustained pellets could prolong the release of DTZ,decrease the fluctuation of drug level in vivo,and increase the compliance of patients.

The enhancing effect and promoting mechanisms of the stereoisomeric monoterpene alcohol esters as enhancers for drugs with different physicochemical properties

To explore the structure-activity connections of amphiphilic permeation enhancers containing the length of the hydrophobic chains as well as the properties of the polar head,O-acylgeraniol and O-acylnerol derivatives were synthesized from geraniol/nerol(cis-isomer of geraniol) and pharmaceutical excipient acids in this research. Their promotion of the percutaneous absorption of three drugs as the model, flurbiprofen(FP), isosorbide dinitrate(ISDN) and donepezil(DNP), which were selected based on their physicochemical properties,was tested by in vitro skin penetration and in vivo. Molecular simulation, ATR-FTIR, CLSM and histological observation were implement to evaluate the mode of action of the enhancers.The results indicated that(E)-3,7-dimethyl-2,6-octadien-1-yl tetradecanoate(GER-C14, trans-)achieved the highest enhancement ability for the three drugs;additionally, the in vivo results obtained were in good correlation with the in vitro data. Molecular docking results suggested that enhancers loosen the hydrogen bonds between ceramides, and the results of molecular simulation indicated that GER-C14, NER-C14 could insert into the middle of the lipid bilayer to form an independent phase. According to ATR-FTIR and histological evaluation, the enhancers extracted lipids and influenced the protein region, thereby disturbing the skin array. In addition, CLSM described the dynamic effects of enhancers on lipids between stratum corneum(SC) cells. In conclusion, GER-C14 had a better penetration promotion effect, which broadened our understanding of stereoisomeric penetration enhancers.

Recent developments in nonferrous metals and related materials for biomedical applications in China:a review

Biomedical materials have received increasing attention in recent decades and have been used in medical applications to advance patient care,such as prosthetic implants,tissue repair and regeneration,drug delivery systems,pharmaceutical or biological therapy products,and sensitive diagnostic technologies.Among different types of biomedical materials,nonferrous metals and related materials(NMRMs)are important and attractive candidates.The updating of biomedical NMRMs and devices heavily relies on original research and applicationoriented innovation.Here,we provide recent research findings and succinct insights into the developments in NMRMs for biomedical applications in China,including the use of titanium,magnesium,copper,zinc,cobalt,zirconium,hafnium,niobium,rhenium,tantalum,tungsten,silver,gold,platinum,palladium,their alloys and compounds,rare earths,high-entropy alloys,and liquid metals.Finally,the literature review concludes with several possible directions of NMRMs for new and future developments in biomedical engineering.