Silica capsules dispersion 20.0ml_ (10%w/w) was left to stand/allowed to cream in a sealed bottle over a day and then, the water dispersant was removed. The cream was then topped up with D.l. water and redispersed to the initial total volume of 20.0mL This process was repeated for another 2 cycles to remove free dissolved CTAB. The washed silica capsules dispersion was then added slowly over 1 min into 20.0ml_ of PCL latex dispersion (5%w/w), which may be purchased or made using conventional techniques such as that described in “Nano-emulsion formulation using spontaneous emulsification: solvent, oil and surfactant optimisation”,Fessi, H. et al. Int. J. Pharm. 2004, 280(1 -2), 241 -251 ” , the contents of which are fully incorporated by reference. The resulting mixture was then heated at 70°Cfor 10 min with stirring and cooled to room temperature. For this step, the pH of the latex solution is alkaline (around 8.5) and pH of the silica capsule solution is acidic (around 3.2). Therefore, it will be appreciated that the pH of the heterocoagulation step can fluctuate between about 3 to about 9.5. It was then filtered and dispersed in 20.0ml_ of D.l water. The hybrid capsules were also purified using similar methods that were described in Example 4. Scanning electron microscopy of (i) silica capsule and (ii) hetero- coagulated silica capsules with polycaprolactone particles FIG. 10A shows the SEM image of original silica capsules. The silica capsules were fragile and break under vacuum conditions used for SEM imaging. Therefore, only broken films were observed. On the other hand, the SEM image of hetero-coagulated silica capsules with polycaprolactone particles (FIG. 10B) shows that the hybrid capsule did not break. As shown, capsules with spherical morphology were observed under SEM