UBC Theses and Dissertations

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UBC Theses and Dissertations

The stability of calcium glucoheptonate solutions Suryanarayanan, Rajagopalan


Calcium glucoheptonate is official in the USP XX as Calcium Gluceptate and is described as the calcium salt of D-glycero-D-gulo-heptonic acid which is the a epimer of glucoheptonic acid. It is freely soluble in water. Since late 1976, solutions of calcium glucoheptonate have shown a tendency to precipitate on storage. The problem of precipitation can be due to one or more of the following reasons: (i) change from an unstable to a stable modification (ii) presence of seed crystals (iii) differing proportions of α and β epimers in the calcium glucoheptonate obtained from various sources Calcium glucoheptonate was found to be amorphous while the precipitate was crystalline. Membrane filtration increased the time taken for precipitation to occur while autoclaving resulted in stable solutions. It can be postulated that the majority of seed crystals are excluded by filtration which results in increased stability and autoclaving destroys the seed crystals. When calcium glucoheptonate from different sources was used for the preparation of solutions, the time for precipitation varied with the commercial source (Table 1). The most stable solution was prepared from a salt described as calcium α - β glucoheptonate and the least stable was supplied as Calcium Gluceptate USP.

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