to bind and then slowly release a relatively large volume of liquid phase materials due to the small spherical nature of the ceramic hydroxyapatite particles it may also act as a lubricant conventional i e non ceramic hydroxyapatite is known to bind to biological molecules including proteins lipoproteins lipids and nucleic acids see for example d josic et al biol chem hoppe seyler 372 149 1991 k j primes et al j chromatography 236 519 1982 s hjerten biochim biophys acta 31 216 1959 g bernardi and w h cook ibid 44 96 1960 r k main et al j am chem soc 81 6490 1959 a tiselius et al arch biochem biophys acta 65 132 1956 however in comparison to ceramic hydroxyapatite conventional hydroxyapatite is produced as particles which are more irregular in shape and in size and also more fragile ceramic hydroxyapatite is also superior to conventional hydroxyapatite in that ceramic hydroxyapatite spheres are resistant to high temperature and pressure and are much more physically stable than conventional hydroxyapatite t kadoya et al j liquid chromatography 9 3543 1986 this physical stability allows for the agitation or mixing of ceramic hydroxyapatite without disintegration of the particles ceramic hydroxyapatite is also more stable chemically than conventional hydroxyapatite being stable for at least five years when stored at room temperature in dry or hydrated form.