GEA and Cambridge Biostability Limited (CBL) have developed a revolutionary method of stabilizing vaccines using spray drying.

Increased Bioavailability

Dr Bruce Roser, Chief Scientific Adviser for CBL, notes: “Using spray drying as opposed to freeze drying increases the availability of these vital drugs. Traditionally, vaccines are made in a batch process. And can take 3 days to manufacture and freeze dry. Spray drying takes seconds and can run continuously until sufficient quantity is made.”

Drugs taken orally can be provided in tablet or capsule form and are, therefore, not susceptible to temperature degradation. Injectables, however, must be kept cool. CBL, with GEA’s help, are pioneering a process that is set to revolutionize drug delivery and make the need for the Cold Chain obsolete, saving an estimated $200–300 million per year and make effective vaccines available to the world’s most vulnerable people.

The process involves mixing the active ingredient with a water-soluble glass-like material, which is then dried into highly polished solid or hollow glass spheres of 3–20 µm diameter. These spheres can be engineered to provide the desired rate of solubility and release. The spheres, containing the stable API, are then suspended in an inert anhydrous syrup such as medically approved fluorocarbons, hydrofluoroethers or low density metabolized oils chosen to match the density of the powder to prevent it floating or sinking. The resulting suspension is a thermostable, ready-to-inject liquid that can be stored and transported at ambient temperature without losing its potency.

Drugs transported in this way can be injected immediately without reconstitution; bodily fluids naturally dissolve the glass spheres to release the active, eliminating the risk of contamination and the need for antiseptics. As the vaccines are themselves inert while in suspension it’s possible to mix vaccines for simultaneous injection, making delivery faster and easier.

Materials and Methods

During the trial period, the spheres were produced under aseptic conditions by spray drying in an GEA AsepticSD™, size ASD –1 spray dryer that enables batches of 10,000 doses to be produced under cGMP conditions.