Microencapsulation is one of the quality preservation techniques of sensitive substances and a method for production of materials with new valuable properties. Microencapsulation is process of enclosing micron sized particles in a polymeric shell. There are different techniques available for the encapsulation of drug entities. The encapsulation efficiency of the micro particle or microsphere or microcapsule depends upon different factors like concentration of the polymer, solubility of polymer in solvent, rate of solvent removal, solubility of organic solvent in water etc. Drug absorption in the GIT is a highly variable process, prolonging gastric retention of the dosage forms and extends the time of the drug absorption. Floating microspheres are prepared with enteric coated polymer (sodium alginate) [successfully by the solvent evaporation technique]. Upon incorporation of the hydrophilic polymer, such as HPMC I the shell of microspheres, the amount of drug released from microspheres could be enhanced. In-vitro data obtained from floating microspheres of felodipine showed excellent flow ability, good buoyancy and prolonged drug release. Microspheres of different size and drug content could be obtained by varying the formulation variables. Thus, the prepared floating microspheres may prove to the potential candidates for multiple unit delivery devices adaptable to any intra-gastric conditions. The formulation were evaluated for various micrometrics and characteristic studies. It increases the bioavailability of dosage form with prolonged effect, hence improves the patient compliance. Mean particle size for all formulations were varied, due to change in drug polymer ratio. True density and tapped density values for all formulations were less than of that gastric fluid (1.004 gm/cm3) exhibits good buoyancy. Angle of repose (<400) for all formulations showed excellent flow ability. Drug release pattern was evaluated in 0.1 N HCl (pH 1.2). Release rate of F1, F2, F6 formulations were found to be slow and incomplete in dissolution medium. Ideal property of floating microspheres includes high buoyancy and sufficient release of drug in pH 1.2. it necessary to selected appropriate balance between buoyancy and drug release rate from all developing floating microspheres. F3 formulation showed best appropriate balance between buoyancy and drug release rate, which can be considered as a best fit for floating microspheres. The design system F3 floats in the stomach and prolongs the gastric residence time (GRT). Consequently, it provides sustained action. In addition, floating microspheres enabled increase drug absorption rate, as it gradually sink in the stomach and arrived at the absorption site. The developed formulation overcomes the drawbacks and limitations of sustained release preparations. Therefore multiple unit floating systems, i.e., floating microspheres will be possibly beneficial for sustained action. When it is formulated in large scale, the formulation will be economical, due to its ease of preparation and buoyancy due to the polymers used in the formulation. Thus, the prepared formulation may reduce the frequency of dosing, thereby minimizing occurrence of side effects, increase residence time in stomach and increase the effectiveness of the drug
