%0 Journal Article
%T Formulation and Characterization of Solid Dispersion Prepared by Hot Melt Mixing: A Fast Screening Approach for Polymer Selection
%A Arno A. Enose
%A Priya K. Dasan
%A H. Sivaramakrishnan
%A Sanket M. Shah
%J Journal of Pharmaceutics
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/105382
%X Solid dispersion is molecular dispersion of drug in a polymer matrix which leads to improved solubility and hence better bioavailability. Solvent evaporation technique was employed to prepare films of different combinations of polymers, plasticizer, and a modal drug sulindac to narrow down on a few polymer-plasticizer-sulindac combinations. The sulindac-polymer-plasticizer combination that was stable with good film forming properties was processed by hot melt mixing, a technique close to hot melt extrusion, to predict its behavior in a hot melt extrusion process. Hot melt mixing is not a substitute to hot melt extrusion but is an aid in predicting the formation of molecularly dispersed form of a given set of drug-polymer-plasticizer combination in a hot melt extrusion process. The formulations were characterized by advanced techniques like optical microscopy, differential scanning calorimetry, hot stage microscopy, dynamic vapor sorption, and X-ray diffraction. Subsequently, the best drug-polymer-plasticizer combination obtained by hot melt mixing was subjected to hot melt extrusion process to validate the usefulness of hot melt mixing as a predictive tool in hot melt extrusion process. 1. Introduction Amorphization of drug increases the solubility of drug because of increased surface area and better ability of the solvent to wet the drug. Such a process can improve the bioavailability of drugs that are poorly soluble, namely, BCS class II and BCS class IV drugs [1¨C3]. For dissolution rate limited drug absorption, molecularly dispersed drug can improve dissolution and thus its absorption [4, 5]. Hot melt extrusion is a solvent free process that utilizes heat and pressure to disperse the drug molecularly in a given polymer-plasticizer combination [6¨C14]. The technique is similar to preparation of solid dispersion by melting method. Formulating a molecularly dispersed form of drug in a carrier matrix requires the optimum amount of drug along with polymer and plasticizer. In some instances a drug (Ibuprofen) itself acts as a plasticizer thus limiting the amount of plasticizer that can be added [8, 15]. Film casting method can be used as preliminary screening technique to determine the right amount of drug-polymer-plasticizer combination that can yield molecularly dispersed drug [16, 17]. The polymer and plasticizer are solubilized in a solvent and applied on a glass plate using a casting device. The film upon drying is visually and microscopically observed to determine any drug precipitation. DSC and X-ray diffraction are other advanced analytical
%U http://www.hindawi.com/journals/jphar/2014/105382/