| The ever-increasing demands on the performance of pharmaceutical formations with respect to,e.g.,storage stability,increased dosage level,greater bioavailability,fewer side effects,controlled release,and biological response (e.g.,tissue distribution) constitute the main motivation for drug delivery research. In the last few decades,this research has resulted in the development of,e.g.,parenteral emulsions,liposomes with improved circulation in the blood stream,cyclodextrins and lipoprotein mimics for cancer therapeutics.Surfactants play a key role in many of the novel drug dilivery systems developed,and a wide range of surfactant-containing systems,including emulsions,liposomes,liquid crystalline phase,and microemulsions,are being extensively investigated in relation to drug delivery.Non-iron surfactants are investigated in our research.according to the phase diagram,we investigated the effects of the elements in the formation of the microemulsions. the ration of the surfactant to the co-surfactant,hydrocarbon length of co-surfactant,HLB value of surfactant,and the structure of oil,the change of additives in the water,the temperature are important in the microemuLsion system.One of the microemulsion studies is its stability.We prepare some microemulsions with the variety of Km(the ratio of surfactant to co-surfactant weight),temperature accelerated test was done to study microemulsion stability.Because microemulsion is the one of the surfactant systems, cloud point is important for the study.when the temperature increase, clouding formation will be seen. as soon as the temperature decreased to the the room temperature, the system will be clear again.it suggestes that microemulsion is self-emusify system without outer energy.Particle size can be chosed to decide microemulsion formula.microemulsion diameter changed with the Km.when Km increased, the diameter would decrease and the diameter of microemulsion loaded drugs increased on increasing the incorporation of drugs.after one month, all microemulsion became smaller and smaller.We chosed the system containd of polyoxyethyl/ethanol/isopropyl /water according to the phase diagram.we prepared the 01W microemulsion contained of different ratio of polyoxyethyl and ethanol.the solubility of Miconazole Nitrate and Indomatacin ,Ibuprofen are compared in the microemulsion and micellar solution:At the same concentration of Miconazole Nitrate and Indomatacin into the microemulsion systems compared with that of a micellar preparation.There is,however,a sigmificant increase over the micellar solutions in the amount of Ibuprofen found in the microemulsion systems.so we can think that the drug carrying improvement of an oil-in-water microemulsion over a micellar system appears to depend on the solubility of the drug in the dispersed oil phase and is significant only for very lipophilic drugs.Cyclosporine A is an effective immunosuppressant for organ transplant patients,it is known that the absolute bioavailability of Cyclosporine A is low due to the poor absorption which is related to the relatively high molecular weight,very highlipophilicity(1ogp~2.92),and poor solubility in aqueous fluids.because of the particle size is tiny,drugs are diffused well to be improved the absorption and lessen the variety between patients.In this study,we prepare Cyclosporine A oral microemulsion solution,HPLC method was chosed to determine the concentration of Cyclosporine A and temperature accelerated test suggested the Cyclosporine A oral microemulsion had been stability at 40 C for 3 month.Pharmacokinetic parameters were calculated after the male rats were orally administrated single dose Cyclosporine A . the bioavaliability of Cyclosporine A loaded microemulsion is compared with Cyclosporine A oral solution and Sandimmun NeoralR.HPLC method determine the concentration of Cyclosporine A in rats blood. Area under the drug concentration-time curve (AUC)were calculated using the trapezoidal rule.the maximal blood concentration of drug(Cmax) and the time to reach m...
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