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Objective: To optimize the formula and preparation technology of cantharidin chitosan bioadhesive microspheres.Methods: The microspheres were prepared by a spray drying method.A single-factor experiment was used to study the effect of chitosan with different molecular weight on the gastric mucosa adhesion rate were also studied, and the effects of different drug loading ratio, concentration of chitosan acetic acid solution and speed of peristaltic pump on the loading rate were also studied.The cantharidin entrapment efficiency as the studying index, a response surface method was used to further optimize the formula.Results: The best formula and preparation process of cantharidin chitosan bioadhesive microspheres were as follows: the concentration ratio of antharidin to chitosan was 19.83% , the concentration of chitosan acetic acid solution was 0.77% , and the peristaltic pump flow rate was 9.225 ml·min-1.With the best formula, the entrapment efficiency of cantharidin chitosan bioadhesive microspheres was 90.14%.Conclusion: The microsphere preparation by the spray drying method is stable and repeatable.Cantharidin chitosan bioadhesive microspheres have high entrapment efficiency and promising biological adhesion.
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Objective Enzyme triggered multi unit colon targeting mini tablet of indomethacin were prepared,in order to improve the target treatment of colon disease.Methods Different proportion of enteric layer and chitosan layer were screened to optimize the prescription.The colon targeting mini tablets were prepared by direct compression method.The drug release properties were investigated in different release medium.Rats were used to investigate the distribution of tissue in vivo.The Beagle dogs were used to study the pharmacokinetics and bioavailability.Results The optimum chitosan layer prescription:coating liquid concentration was 2％,plasticizer three citric acid ethyl ester (TEC) was 15％,an anti sticking agent amount of talc was 30％,coating weight was 5％;Enteric layer prescription:coating liquid solid content was 20％,plasticizer content of TEC was 5％,anti sticking agent talc powder dosage was 40％,coating weight was 3％.The chitosan multi unit colon targeted preparation seldom released in rat stomach and small intestine,released slowly in colon.The pharmacokinetics parameters in Beagle dogs were:Cmax =(3.25 + 0.672) mg·L-1,tmax =(2.00 + 0.014) h,AUC(0.∞) =(10.2 +0.871) mg·L-1 ·h,MRT (0-∞) =(2.82 + 0.180) h,CL =(2.46 + 0.202) L·h-1 ·kg-1.The release time of mini tablets for colon targeted was significantly prolonged and preserved stable blood concentration.Conclusion The enzyme triggered multi unit colon targeting mini tablet of indomethacin showed good target to colon and sustained release effect,providing an important reference for the development of preparation of indomethacin for the treatment of colon disease.
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Cell-penetrating peptides (CPPs) offer a non-selective and receptor-independent mode to promote cellular uptake. Although the non-specificity of CPP-mediated internalization allows this approach applicable to a wide range of tumor types potentially, their universality is a significant obstacle to their clinical utility for targeted delivery of cancer therapeutics and imaging agents. Accordingly, many reports have focused on selective switching of systemically delivered inert CPPs into their active form in lesions (tumor). In this review, our attention is mainly confined to such an enzyme-sensitive domain incorporated delivery system with activatable CPPs (ACPPs), which have displayed the exciting strength in balancing the CPPs' pros and cons, and potential in the treatment and diagnosis of some diseases.
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This paper reported that a new type of floating osmotic pump of ambroxol hydrochloride was designed. Third method apparatus (Chinese Pharmacopeia 2010, appendix XD) was employed to simultaneously evaluate the release and floating behavior in vitro. The system was optimized using central composite design-response surface methodology. Similar factor (f2) between the release profile of self-made formulation and the target release profile was chosen as dependent factor. The amount of glucose (A, mg), pore former (B, %) and weight of coating (C, %) were employed as independent factors. Optimized formulation was: A (100.99 mg), B (1.70%), C (4.21%). The value of f2 (89.14) was higher than that of market capsules (69.02) and self-made tablets (72.15). It was showed that self-made capsules possessed character of zero-order release (r = 0.994 4) and drug release completely (>90%). It was showed in result of in vivo study that tmax and Cmax of self-made capsules were significantly lower than that of market capsules and self-made tablets. The correlation coefficient between the fraction of absorption in vivo and the release rate in vitro was 0.985 1, and relative bioequivalence of self-made capsules was 110.77%. Accordingly, self-made capsules displayed obviously characteristics of controlled release both in vivo and in vitro.
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Background The anti-proliferative effect of matrine has been demonstrated and its relevance to prevention and treatment of proliferative retinovitreopathy is concerned.Howeverthe intravitreous injection of free-matrine reiteratively may raise the risk of ocular infection.ObjectiveThe goal of the present study is to investigate the sustained releasing ability and safety of matrine polyactic acid microsphere(MAT-PLA-MSintravitreal injection.MethodsMAT-PLA-MS was prepared by Hebei Medical University and examined under the transmission electron microscope.The release of MAT-PLA-MS was monitored by ultraviolet spectrophotometry.Free-matrine with the dose of 1,2,4mg was intravitreally injected respectively in 12 eyes of New Zealand albino rabbits in free-matrine group and MAT-PLA-MS with matrine(2,4,6mg respectively was administered in 16 eyes separately in matrine microsphere group.The blank microsphere was injected in 6 right eyes as blank control group and normal saline solution was injected in 6 fellow eyes as control group.The retinal function change was evaluated by electroretinogram(ERG),and the morphological and histological change of retina following drug injection were assessed under the slit lamp biomicroscope,indirect ophthalmoscope,light microscope and transmission electron microscope.The decomposed process of MAT-PLA-MS in vitreous was recorded with ocular anterior segment and fundus color camera.Results MAT-PLA-MS containing matrine showed the spherical shape with the mean diameter of 2.28±47μm under the transmission electron microscope and the drug-loading rate 6.17% and drug-release rate 87.93% in vitro for 672 hours,presenting the controllable release characteristics.After implantation into the vitreous,the MAT-PLA-MS containing matrine decomposed gradually with the prolong of time.The b amplitudes of ERG maximum response were significantly declined in 4mg free-matrine injection group in comparison with before injection in various time points(P<0.01).However,no considerably differences were found in MAT-PLA-MS with matrine groups and control groups in various time points following the intravitreal injection(P>0.05).No obvious abnormal was seen under the slim lamp and ophthalmoscope through the study period.The changes of retinal ultrastructure were found from 1 through 28 days after injection of 4mg free-matrine,and slight retinal structural damage was seen from 7 through 28 days after injection of 6mg MAT-PLA-MS containing matrine.ConclusionThese results suggest that MAT-PLA-MS possesses good sustained release feature.MAT-PLA-MS containing matrine has less toxicity to retina than free-matrine after intravitreal injection.MAT-PLA-MS is an excellent drug delivery system.
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Objective To study the determination of biological activity of ?_1-AT with chromogenic substrate and its influential factors using fresh pooled normal human plasma as reference standard.Methods Measuring absorption value of reactions between residual trypsin and BAPNA at 405nm,after ?1-AT inhibition by excess trypsin.Fresh pooled normal human plasma was used as reference standard to calculate the biological activity of?1-antitrypsin.Results Good linear correlation was obtained when the plasma was diluted to 1/50 to 1/100.PEG4000,sucrose,S/D(Tween80/TNBP) and sodium caprylate did not influence the biological activity of ?1-AT,but?1-AT activity was increased by about 20% when the concentration of sodium citrate was above 0.125mol/L.Conclusion The experiment proved that?1-AT biological activity was determined using fresh pooled human plasma as reference standard,the method is stable and reliable.Except sodium citrate,all of the materials used in the assay did not influence the determination of?1-AT activity.