The effect of formulation variables on the dissolution and physical properties of spray-dried microspheres containing organic salts

In the present work, the spray drying technique was used in formulating calcium microparticles from aqueous systems: dispersions of calcium citrate and solutions of calcium lactate were incorporated with polymers and dispersed into a hot air stream as small droplets, leading to the formation of solid microparticles. Different kinds of polymers (cellulose derivatives and polymethacrylic acid) were studied to evaluate their spray-coating properties and the release profiles. In addition, some physical properties of the microparticles were also determined. The results showed that the calcium release from the microparticles containing both organic calcium salts into a simulated gastrointestinal medium, as well as the microparticles size and morphology can be modified by varying the proportion and the type of the polymer used as encapsulating agent.