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The thermally induced interactions of sodium alendronate trihydrate in 1:1 mass ratio binary mixture with talc, silica, magnesium stearate, microcrystalline cellulose, starch, gelatin and mannitol were studied under nonisothermal conditions. The heat flow (HF) signal, obtained by converting the temperature differences (DTA) into power units, was used for detecting the thermally induced events. By all the seven excipients, no thermally induced interactions with alendronate were observed, but the thermal stability of the excipients is very different. The talc and silica, as expected, are very thermostable. By starch, gelatin, and microcrystalline cellulose, the HF signal corresponding to the thermo degradation is over 270°C, the deamination step of alendronate. The magnesium stearate and mannitol substances are not recommended for solid formulation due to its low thermal stability.

A good bone augmentation and regeneration depends essentially on the use of a high biomimetic hydroxyapatite, respectively of an osteoclast apoptosis promoting compound. The last one, used in oral or injectable form, leads to different gastrointestinal side effects. We suggested and studied, at non-clinical level, a composite of sodium alendronate linked on a biogene hydroxyapatite. The composite was obtained by putting an aqueous solution of alendronate into a suspension of hydroxyapatite in acetone. By physico-chemical methods the binding of alendronate (ALE) on hydroxyapatite was proved, the content of ALE in the composite being 22%. The patients can benefit from this composite due to a total elimination of gastrointestinal side effects as a consequence of limiting the bioactivity only locally.