We claim:
1. A process for the preparation of Sugammadex sodium (1), comprising: a) reacting gamma cyclodextrin (4)
with suitable halogenating agent in a suitable organic solvent to provide 6-per-deoxy-6-perchloro gamma cyclodextrin (3);
b) reacting the 6-per-deox-6-perchloro gamma cyclodextrin (3) with mercaptopropionic acid (2) or its salt or its ester

in presence of base to yield Sugarnmadex sodium (1); and c) purifying Sugarnmadex sodium (1), wherein the purification comprises; i. providing a solution of Sugarnmadex sodium (1) in a suitable
solvents or mixture thereof; ii. isolating Sugarnmadex sodium (1) by adding suitable solvent at
a suitable temperature; iii. optionally, converting Sugarnmadex sodium (1) to free acid (5)
and dissolving in a suitable biphasic solvents; iv. isolating Sugarnmadex free acid (5) by cooling to a suitable
temperature; v. optionally, converting Sugarnmadex free acid (5) to sodium salt
(1) and dissolving in water; vi. passing aqueous Sugarnmadex sodium (1) solution through flash
column chromatography loaded with reverse phase silica gel; and vii. isolating pure Sugarnmadex sodium (1) by evaporating the pure
fractions.
2. The process as claimed in claim 1, wherein the suitable halogenating agent is selected from the group comprising of methane sulfonyl chloride, methane sulfonyl bromide, oxalyl chloride and oxalyl bromide.
3. The process as claimed in claim 1, wherein the salts and esters of mercaptopropionic acid (2) is selected from a group comprising of sodium mercaptopropionic acid, potassium mercaptopropionic acid, methyl-3-mercaptopropionate, ethyl-3-mercaptopropionate, isopropyl-3-mercaptopropionate.
4. The process as claimed in claim 1, wherein the suitable base is selected from a group comprising of sodium hydride, potassium hydride, sodium methoxide, sodium ethoxide, potassium methoxide, sodium tertiary butoxide, potassium tertiary butoxide; sodium carbonate, potassium carbonate and cesium carbonates.

5. A compound of Sugammadex sodium (1) having purity greater than 98.0% by
HPLC and one or more of the following:
i. impurity A less than 2.0%(w/w); and ii. impurity E less than 0.1 %(w/w)
6. The process as claimed in claim 5, wherein the purification process of
Sugammadex sodium (1), having purity greater than 98.0%
comprises of:
A. providing a solution of Sugammadex or its salts in a suitable solvents or
mixture thereof;
B. cooling the solution to suitable temperature;
C. isolating Sugammadex or its salts by adding suitable protic solvent;
D. optionally, providing a solution of Sugammadex in a suitable biphasic
solvent;
E. stirring the biphasic solution of Sugammadex at suitable temperature;
F. isolating Sugammadex or its salts by cooling to a suitable temperature;

G. optionally, dissolving Sugammadex or its salts in water at suitable
temperature; H. passing aqueous Sugammadex salt solution through flash column
chromatography loaded with reverse phase silica gel; and I. isolating pure Sugammadex or its salt by evaporating the pure fractions.
7. The process as claimed in claim 1 and claim 6, wherein the suitable solvent used herein is selected from water and suitable water miscible acid selected from the group comprising of hydrochloric acid, sulfuric acid, formic acid, acetic acid, propionic acid or mixture thereof.
8. The process as claimed in claim 1 and claim 6, wherein the suitable biphasic solvent system is selected from group comprising mixture of water and organic solvent. water immiscible solvent is selected from a group comprising of hexane, heptane, cyclohexane, toluene, methyl acetate, ethyl acetate, isopropyl acetate, diethyl ether, di isopropyl ether, dibutyl ether, di-tertiary-butyl ether, methyl tert-butyl ether, ethyl tertiary butyl ether, methyl t-butyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, dimethylformamide, dimethylfuran, or mixture thereof.
9. A process for the purification of Sugammadex sodium (1) having purity greater than 98%, which comprises of:
a. providing a solution of Sugammadex sodium (1) in water at suitable
temperature;
b. passing aqueous Sugammadex sodium (1) solution through flash column
chromatography loaded with reverse phase silica gel; and
c. isolating pure Sugammadex or its salt by evaporating the pure fractions.

10. The process according to claim 9, wherein the suitable reverse phase silica gel used is selected from C8 and Cl8 silica gel.