Discos de poco espesor de hidroxiapatita cubana sinterizada como sistema de liberacion de fármacos / Cuban low-thickness sintered hydroxyapatite disks as a drug release system

Objetivo: el objetivo principal de este trabajo es estudiar la posibilidad de que sean empleados como sistema de liberación controlada de fármacos, discos de Hidroxiapatita (HA) cubana, fabricados por prensado y sinterizado en hornos eléctrico, sin el empleo de agentes formadores de poros, con porosidades aparentes de 12, 20 y 40 por ciento que fueron dopados por sobre presión con una solución acuosa de alginato de sodio al 5 por ciento y 55 ppm de ceftazidima. Métodos: se estudió la relación entre la penetración del polímero y la porosidad aparente con la liberación del fármaco. Resultados: se demostró que estos discos infiltrados con el polímero que encapsula el fármaco pueden ser utilizados como sistema de liberación controlada. Se demuestra que la porosidad aparente y el tamaño de los poros son influyentes en la penetración del polímero y la masa de fármaco liberado. Conclusiones: En las curvas de liberación obtenidas se observa que los discos pueden ser un potencial material para soportar medicamentos porque se evidencia como el material es capaz de controlar la liberación del medicamento remanente ocluido por un método de dopaje a sobre presión.El perfil indica que en un periodo de siete días se libera controladamente el medicamento

Objective: the main purpose of this study is to examine the potential use of Cuban hydroxyapatite (HA) disks as a controlled drug release system. These disks are manufactured by pressing, and sintered in electric furnaces without using pore-forming agents, with apparent porosities of 12, 20 and 40 percent , and doped by overpressure with a 5 percent sodium alginate aqueous solution and 55 ppm ceftazidime. Methods: a study was conducted of the relationship between penetration of the polymer and apparent porosity with the release of the drug. Results: it was shown that when infiltrated with the polymer encapsulating the drug, these disks may be used as a controlled release system. It was also found that apparent porosity and pore size influence polymer penetration and the mass of drug released. Conclusions: the release curves obtained show that the disks may be a potential drug-supporting material, capable of controlling the release of the remnant drug occluded by an overpressure doping method. The profile reveals that controlled release of the drug is completed in seven days

An Overview: Matrix Tablet as Controlled Drug Delivery System.

In past decade great interest got generated on replacing conventional administration of drug by delivery system which would release effective quantities from a protected supply at a controlled rate over a long period of time. An appropriately designated controlled release drug delivery system can be are major advance toward solving problems concerning targeting of a drug to a specific organ or a tissue and controlling the rate of a drug delivery to the target site. Matrix system are favoured because of their simplicity, patient compliance etc, than traditional drug delivery(TDS) which have many drawbacks like repeated administration, fluctuation in blood concentration level etc. Developing oral sustained release matrix tablet with constant release rate has always been a challenge to the pharmaceutical technologist. Most of drugs, if not formulated properly, may readily release the drug at a faster rate, and are likely to produce toxic concentration of the drug on oral administration. Hydrophilic polymers have become product of choice as an important ingredient for formulating sustained release formulations.

Novel oral sustained release technology: A concise review.

The advantage of administering a single dose of a drug that is released over an extended period of time instead of numerous doses is now a day’s area of interest for formulation scientists in Pharmaceutical industry. There are several advantages of sustained release drug delivery over conventional dosage forms like improved patient compliance due to less frequent drug administration, maximum utilization of the drug, increased safety margin of potent drug, reduction of fluctuation in steady-state drug levels, reduction in healthcare costs through improved therapy and shorter treatment period. Wide varieties of polymers like Hydroxy Propyl Methyl Cellulose (HPMC), Carboxy Methyl Cellulose (CMC), Ethyl Cellulose (EC), Cellulose Acetate Phthalate, HPMC K100M, Xanthan gum, Carrageenan gum, Karaya gum, HPMC K15, Carbopol 971P and Carbopol 974P etc. are available for retarding the release rate of drugs hence sustains the action of drugs. This review article describes the basic information regarding sustained-release formulation, its advantages, disadvantages, selection of drug for sustain release, mechanism of release, different types, and factor involved in oral sustained-release dosage form design.

Current research of diabetic macular edema / 中华实验眼科杂志

Diabetic macular edema (DME) is a leading cause of vision loss in diabetic patients.It is very important to correctly select a treating approach for DME.At present,the treating methods of DME include retinal laser photocoagulation,application of the glucocorticoid,intravitreous injection of anti-vascular endothelial growth factor (VEGF) drugs,administration of inhibitor of protein kinase C,vitrectomy and combined treatment etc.However,each method has its advantage and disadvantage.Retinal photocoagulation,vitrectomy,intravitreous injection and drug delivery system implantation are invasive treatment methods,and they can not rescue damaged retinal photoreceptors.Therefore,it is recommended that DME should be early diagnosed and effective treatment.The research status at home and abroad and future development trends of DME treatment were summarized.

Construction of a new type of active skin substitutes for tissue engineering / 中华医学美学美容杂志

Objective To discuss the possibility of constructing a new kind of active skin substi tutes.Methods The culture of dermal fibroblasts were isolated from foreskin of an infant; preparation of human acellular amniotic extracellular matrix was conducted through the disposition of detergent and enzyme.Surface structure porosity and pore size were detected through scanning electron microscopy.bFGF-chitosan gelatin microspheres were prepared.The features such as the size distribution,drug content,drug encapsulating and in vitro release were studied with scanning electron microscopy,laser grainsize analyzer and ELISA method.MTT test was performed to observe cell proliferation and evaluate the biocompatibility in vitro.Results The cellular layer of amniotic membrane was completely removed but did not damage the collogen scaffolds structure by the disposal of enzyme and detergent.Scanning electron microscopy showed that the scaffolds had criss-cross structure and high porosity,the pore size was irregular and varied from 10 nm to 100 nm.Scanning electron microscopy of bFGF- gelatin-chitosan microspheres surface structure showed that the microspheres had spherical structure,uniform size and smooth surface quality.Controlled release curve showed that the sudden release of bFGF was obvious.Conclusions A new type of active skin substitutes is prepared through culturing fibroblasts on HAAM loaded controlled-released basic fibroblast growth factor from chi tosan-gelatin microspheres.

Development of a hydrogel microsphere delivery system for rhBMP2 / 实用口腔医学杂志

Objective: To design and synthesize a novel vector for rhBMP2 delivery system in tissue engineering. Methods:Dextran glycidol methacrylate(dex-GMA) was synthesized with dextran(dex) and glycidol methacrylate(GMA).Dex-GMA microspheres were prepared by suspension polymerization. The swelling behavior of the microspheres was evaluated by the swelling equilibrium parameter Q. The biodegradation properties of the dextran-based hydrogel microspheres were assessed by the surface morphology before and after biodegradation. Results:Microspheres of dex-GMA in the size(diameter) of 20 to 80 ?m with good configuration were produced. Q value of the microspheres with the diameter of 20-30 ?m was 10.9?3.3,that of those with 70-80 ?m 8.9?6.4.Stirring speed, span-80(emulsifer) quantity and the proportion of dex-GMA affected the size of the microspheres. rhBMP2 was enveloped into the microspheres. Complete degradation of the microspheres was observed during 20 to 40 days at 37 ℃ in normal saline. Conclusion: Dex-GMA hydrogel microspheres may be a release controlling system for rhBMP2 delivery.