Disclosed herein is a sustained release hollow core-shell microcapsule formulation for drug delivery comprising a hollow shell of one or more hydrophobic polymers, a drug containing hydrophilic or amphiphilic carrier matrix that is distributed over the inner surface of the hollow shell, a flotation agent, and an optional osmotic agent, wherein the microcapsule is capable of floating in a simulated digestive fluid for a period of from 24 to 96 hours. The microcapsules are prepared by a modified double emulsion (water/oil/water) solvent evaporation method. The microcapsule formulation may provide a sustained-release delivery system for treating chronic diseases such as Parkinson's disease, diabetes and tuberculosis, all of which require multiple drug combination therapies. The aim is to reduce dosing frequency and pill burden, thus improving patient medication compliance. In a specific embodiment, the hollow shell is formed from a mixture of Poly-L-lactide (PLLA) and poly(E-caprolactone) (PCL)； and the amphiphilic carrier matrix is casein.
