Calcium phosphate emulsions: Possible applications

A hydrophobic liquid was mixed with a calcium phosphate cement paste and an emulsifier. After intensive mixing, an emulsion was formed. The emulsion was either a W/O emulsion (cement droplets dispersed in oil) or a O/W emulsion (oil droplets dispersed in the cement paste), depending on the emulsifier type and the oil stability. The stability of the two types of emulsion could be well predicted using the hydrophilic-lipophilic balance concept. After the cement had set and the oil had been washed off, calcium phosphate granules or porous blocks were obtained. The composition of the granules and the blocks was either calcium-deficient hydroxyapatite (before sintering) or beta -tricalcium phosphate (after sintering). An increase of the emulsifier concentration or a decrease of the oil amount led to a decrease of the block pore size.