Preparation of microspheres and Nanospheres for Optimum Drug Delivery in Volume Sensitive Applications

Abstract

Drug delivery is the method or process of administering a pharmaceutical compound to achieve a therapeutic effect in humans or animals. Efforts in the area of drug delivery include the development of targeted delivery in which the drug is released over a period of time in a controlled manner from a formulation. Types of sustained release formulations include loaded biodegradable microspheres and nanospheres. This research is carried out to achieve successful drug delivery through loaded biodegradable microspheres and nanospheres for volume sensitive applications in the human body. The microspheres can be implanted as compressed tablets in the targeted area of the body; whereas the nanospheres can be injected into the body in a dispersed form in volume sensitive areas of the body. These areas mainly include the retina of the eye where volume is the most important factor. The benefit of using biodegradable polymers is that the polymers degrade inside the body after a period of time and hence there is no surgical removal of any implant necessary, which is patient favorable. In this study, matrix tablets with poly (lactide-co-glycolide) (PLGA) and poly (lactic acid) (PLA) particles and drug pellets are prepared by direct compression to evaluate the effects of altering PLGA/PLA particle size and compression pressure on the release rates of the drug from matrix tablets. Different release mechanisms based on the end application are also proposed and discussed. PLGA/PLA microparticles and nanoparticles were prepared by a modified in-emulsion-solvent-evaporation method. Tablets were prepared by direct compression of the particles recovered. The tablets' physical characteristics including weight, dimensions and density were examined. The tablets were then used for a drug release study. A UV plate reader measured the amount of drug released. The readings were then converted into concentration and the sustained drug release profiles were obtained. The profiles for microspheres and nanospheres are compared along with the different compression pressures used and the different release procedures based on the method of drug delivery to be used.