1. A process for the preparation of Calcium gluconate (1),
wherein the process comprising the steps of:
a) reacting gluconic acid sodium salt (4)
with an acid to provide gluconic acid (3);
b) cyclizing gluconic acid (3) to provide D-Glucono-1,5-lactone (2).
c) reacting D-Glucono-1,5-lactone (2)
with calcium carbonate (3) in water to obtain Calcium gluconate crude (1);
and
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d) purifying crude Calcium gluconate (1) to obtain pure Calcium gluconate (1),
wherein the purification process comprises;
i. adding Norit CN1 carbon to the crude calcium gluconate (1),
ii. seeding the reaction mass obtained in step-i),
iii. isolating the pure Calcium gluconate (1).
2. The process as claimed in the claim 1, wherein the acid used in step a) is
selected from hydrochloric acid, hydrobromic acid, nitric, carbonic,
monohydrogencarbonic, phosphoric, monohydrogenphosphoric, dihydrogen
phosphoric, sulfuric, monohydrogensulfuric, hydriodic, or phosphorous acids
and the like.
3. The process as claimed in claim 1, wherein Calcium gluconate (1) obtained
after purification is having purity greater than 99.5% by High performance
liquid chromatography (HPLC).
4. The process as claimed in claim 1, wherein the crystalline form of Calcium
gluconate monohydrate (1) is characterised by X-ray powder diffractions
(XRD) pattern comprising of 2 theta values at 7.37, 8.15, 9.18, 15.51, 16.16,
17.43, 19.11, 19.43, 20.19, 20.50, 20.91, 22.00, 22.61, 23.24, 23.78, 24.03,
24.47, 26.70, 27.27, 27.44, 28.28, 37.73, 38.24, 40.41 and 40.74 ±0.2 degrees.
5. The process as claimed in claim 1, wherein the Calcium gluconate
monohydrate (1) is having loss on drying less than 1.0 % by weight.
6. The process as claimed in claim 1, wherein the Calcium gluconate
monohydrate (1) is having less than about 0.005% by weight of chloride, less
than about 0.005% by weight of sulfate, less than about 0.01% by weight of
phosphate; less than about 2.0 mg of magnesium and alkali metals.
7. The process as claimed in claim 1, wherein the Calcium gluconate
monohydrate (1) is having less than about 5.0 ppm of iron; less than about 1.25
ppm of aluminium; less than about 1 ppm of arsenic.