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
. A PHARMACEUTICAL FORMULATION FOR PARACETAMOL INJECTION
2. APPLICANT (S)
(a) NAME : Lincoln Pharmaceuticals Limited.
(b) NATIONALITY: an Indian Company
(c) ADDRESS : Nirav Complex, Opp. Navrang High School
Naranpura, Ahmedabad-380014 Gujarat, India.
3. PREMABLE TO THE DESCRIPTION

PROVISIONAL
The following specification describes the invention.

COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

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18 AUG 2008

The present invention relates to a pharmaceutical formulation for paracetamol injection that provides ease of administration to the patient, less pain to the patient and high effectiveness.
More particularly, the present invention relates to ready to use paracetamol injection in which no dilution is required at the time of injecting solution. Background of the Invention:
Paracetamol is the active metabolite of phenacetin a so-called coal tar analgesic. It has analgesic and antipyretic effects. (L. Jackson Robers II and etal., Chapter 27 Analgesic-antipyretic and anti-inflammatory agents; Goodman & Gilman's The pharmacological basis of therapeutics; Edition 10; McGraw-Hill Medical publishing Division; Page: 703)
Generally paracetamol is formulated as tablets or other solid forms. Though paracetamol is scarcely soluble in water some difficulties arises in solutions preparation. Other problem is hydrolyzing of paracetamol to p-aminophenol in presence of water and/or on exposure to light.
It will have an advantage of making it more water soluble. It is used in post-operative care and is delivered by I.V.. It is given if the patient is unable to take oral or rectally delivered paracetamol and non-steroidal anti-inflammatory drugs are contraindicated. The onset of analgaesia from propacetamol is more rapid than paracetamol is given orally. (www.wikipedia.com)
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Several attempts had been done to overcome these problems.
In WO 98/05314 a composition containing a solution of paracetamol is prepared in an aqueous solvent in combination with a buffer having a pH from 4 to 8 and an agent capable of capturing free radicals. Oxygen present in the said solvent is removed by means of flushing with a water-insoluble inert gas.
WO 0007588 describes paracetamol solution, which comprises paracetamol, 1 to 4 parts by volume of a low molecular weight alcohol for each part by weight of paracetamol, 1 to 5 parts by volume of a polyethylene glycol for each part by weight of paracetamol, and 4-10 parts by volume of water for each part by weight of paracetamol. However, this solution is not ready-to-use, but must be reconstituted prior to injection, by adding a given quantity of water. This sets a limit to the practical use of the product.
EP 1465663 discribes ready-to-use stable paracetamol injectable solutions which is .prepared by mixing paracetamol, water,propylene gycol and a citrate buffer. In this invetnion preferable concentration of paracetamol is up to 4% w/v (%g/100ml).
Thus not a single invention is providing a paracetamol injecatable solution that can be stable, ready-to-use less viscous and providing high concentration of paracetamol in a small amount of solution.
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Objects of the Invention:
The main object of the present invention is to prepare a pharmaceutical formulation of paracetamol that provide ease of administration to the patient, less pain to the patient and high effectiveness.
Another object of the present invention is to prepare less viscous injectable formulation of paracetamol.
Further object of the present invention to prepare ready to use solution due to which there is no need of dilution Summary of the Invention
The present invention refers to a pharmaceutical formulation for paracetamol injection which comprises paracetamol, glycofurol, co-solvent, water and preservative. This formulation provides ease of administration to the patient, less pain to the patient and high effectiveness. The said formulation is ready to use formulation so no dilution is required at the time of injecting solution. Detail Description
In the present invention less viscous pharmaceutical formulation of paracetamol is prepared.
Paracetamol is used in a concentration of 6-15 % w/v (% mg/ml). 15%, 10% and 6% of paracetamol is used for 2 ml, 3 ml and 5 ml of injection respectively.
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Glycofurol is used in a concentration of 22-44 % v/v (% ml/ml). 44%, 36% and 22% of glycofurol is used for 2 ml, 3 ml and 5 ml of injection respectively.
If required then alcohol is used as a co-solvent in a concentration of 10% v/v (% ml/ml). Quantity sufficient water is used in the present invention. Sterile water for pharmaceutical use is used. The concentration of solvents and co-solvents are kept at a level so that Paracetamol does not crystallize out at a temperature of 2 degree C.
Benzyl alcohol 1- 2 % v/v (% ml/ml) is used as a preservative.
The pharmaceutical composition of the present invention can be prepared according to techniques that are well known in pharmaceutical chemistry, comprising mixing, dissolution, sterilization and like.
The invention is illustrated more in detail in the following examples. The examples describe and demonstrate embodiments within the scope of the present invention. These examples are given solely for the purpose of illustration and are not to be construed as limitations of the present invention, as many variations thereof are possible without departing from the spirit and scope. Example 1:
Ingredients Quantity per ml
Paracetamol 150 mg ( 15 % w\v)
Glycofurol 0.44 ml (44%v\v)
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Alcohol

0.10 ml (10%v\v)

Benzyl alcohol Water for Injection

0.02 ml (2 % v\v) q.s. 1.0 ml

Example 2:

Ingredients
Paracetamol
Glycofurol
Benzyl alcohol
Water for Injection

Quantity per ml
150 mg(15%w\v)
0.48 ml ( 48 % v\v)
0.01 ml(l%v\v)
q.s. 1.0 ml

Example 3:

Ingredients
Paracetamol
Glycofurol
Benzyl alcohol
Water for Injection

Quantity per ml
100 mg (10%w\v)
0.36 ml (36%v\v)
0.01 ml(l%v\v)
q.s. 1.0 ml

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Ingredients
Paracetamol
Glycofurol
Benzyl alcohol
Water for Injection

Quantity per ml
60 mg ( 6 % v\v)
0.22 ml(22%v\v)
0.01 ml(l%v\v)
q.s. 1.0 ml

We Claim:
1. A pharmaceutical formulation for paracetamol injection comprises paracetamol, glycofurol, co-solvent, water and preservative.
2. The pharmaceutical formulation for paracetamol injection as claimed in claim 1 wherein 6-15 % w/v paracetamol is used.
3. The pharmaceutical formulation for paracetamol injection as claimed in claim 2 wherein 15% w/v paracetamol is used for 2 ml injectable solution.
4. The pharmaceutical formulation for paracetamol injection as claimed in claim 2 wherein 10% w/v paracetamol is used for 3 ml injectable solution.
5. The pharmaceutical formulation for paracetamol injection as claimed in claim 2 wherein 6% w/v paracetamol is used for 5 ml injectable solution.
6. The pharmaceutical formulation for paracetamol injection as claimed in claim 1 wherein 22-44 % v/v glycofurol is used.
7. The pharmaceutical formulation for paracetamol injection as claimed in claim 6 wherein 44% glycofurol is used for 2 ml injectable solution.
8. The pharmaceutical formulation for paracetamol injection as claimed in claim 6 wherein 36% glycofurol is used for 3 ml injectable solution.
9. The pharmaceutical formulation for paracetamol injection as claimed in claim 6 wherein 22% glycofurol is used for 5 ml injectable solution.
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10. The pharmaceutical formulation for paracetamol injection as claimed in claim 1 wherein alcohol is used as a co-solvent in a concentration of 10% v/v for 2 ml injectable solution.
11. The pharmaceutical formulation for paracetamol injection as claimed in claim 1 wherein 1- 2 % v/v Benzyl alcohol is used as a preservative.
12. The pharmaceutical formulation for paracetamol injection as claimed in claim 1 wherein quantity sufficient water is used.
13. The pharmaceutical formulation for paracetamol injection as described herein before and with reference to the foregoing examples.
Dated this 14th day of August 2008.

Dr. Rajeshkumar H. Acharya
Advocate & Patent Agent
For & on behalf of the Applicant.
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