FORM 2
THE PATENT ACT, 1970
(39 of 1970)
The patents rules, 2003 COMPLETE SPECIFICATION
(See section 10 and rule 13)
1.TITLE OF THE INVENTION
"PARENTERAL SOLUTION OF TRAMADOL"
2. APPLICANT
(a) Name: UMEDICA LABORATORIES PVT. LTD
(b) Nationality: INDIAN
(c) Address: 105/108, REWA CHAMBERS, lst fl, 31, NEW MARINE LINES, MUMBAI
400020. MAHARASHTRA, INDIA
3. PREAMBLE TO THE DESCRIPTION
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION:
The present invention relates to novel injectable pharmaceutical compositions of tramadol or salts thereof, comprising sterile solution of tramadol or salts thereof and are free from additives or excipients. The present invention also relates to stable injectable pharmaceutical compositions of Tramadol or salts thereof, wherein pH of the injectable compositions is maintained from about 4 to about 7 by using an acid.
BACKGROUND OF INVENTION:
Tramadol is a synthetic analgesic used in the treatment of moderate to severe pain. It is a centrally acting weak µ-opioid receptor agonist which induces serotonin release, and inhibits the reuptake of norepinephrine.
Tramadol, (1R,2R)-rel-2-[(dimethylamino)methyl]-l-(3-methoxyphenyl)cyclohexanol is commonly used in its hydrochloride salt. It is administered as 25mg per day to not exceeding 400mg per day depending on severity of disease condition. Tramadol hydrochloride is commercially available in tablets, capsules, suppositories, powders and parenteral solution in several countries.
Commercially available Tramadol injections consist of sodium acetate as a buffer system to maintain the pH of solution.

There are patents in prior art which depict the use of tramadol in parenteral dosage form.
U.S. patent No. 6875447 discloses parenteral delivery of Tramadol and diclofenac in the form of
suspension where atleast 95% of suspended salt has particle size