Back ground of Invention with regard to the drawback associated with the known art:
Sterile and pyrogen free water for injection (WFI) is an essential material for field medical operations, for producing intravenous fluid and reconstituted freeze dried product for injection which requires parenteral procedures. The elimination of all living organisms (sterilization) and fever causing agents i.e. pyrogens (depyrogenation) can be accomplished by physical methods (heat), chemical agents, radiation or mechanical methods (filtration). In addition to sterilization and depyrogenation, injectable water must be free from particulate matter, oxidizable substances, dissolved gases and metals. So the way to manufacture WFI is distillation and reverse osmosis. Both of them have limitations when intended for field deployment
The disadvantages of the known process and apparatus comprising the semi permeable membranes is that the membranes must be continually subjected to the action of water and the membranes of this system were not of sufficient configuration to enable the sterilant to reach all portions of the membrane surface. Reverse osmosis, deionization and ultrafiltration are capable of producing chemically and biologically pure water for short periods of time. These systems will maintain low levels of bacteria and pyrogen upto 2 weeks. After this period, colonies of biologically active material such as bacteria, yeast and mold will start growing and start contamination of pure water. These systems can regain their capacity by rinsing systems with sanitizing agent such as formalin or chlorine. They are highly toxic to humans and are difficult to rinse out of the purification system. Distillation and reverse osmosis physically separate pyrogen from water but neither destroys the pyrogens. Distillation operated under low pressure is bulky and heat recovery is limited. The pyrogen concentrated in

the solution are still residues or reverse osmosis retentate must be purged continuously or intermittently from the system. Distillation makes WFI expensive. Another method is by using membrane filter systems which removes all living organisms. A pasteurization process is also described in the prior art. To produce WFI, both of these methods require additional treatment steps, involving active carbon filters, deionizers, and ultrafiltration filters. So there is lack of final heat sterilization method. WFI must be apyrogenic and free from suspended particles.
Producing, transporting and storing sufficiently large amounts of WFI is a key logistical problem. To overcome this problem, there is a need for development of a compact, reliable, and automatic system that can continuously produce sterile and pyrogen free WFI from portable water sources. Process for producing sterile water for injection from potable water is disclosed in the prior art having US patent no. 6858179. This process describes the combination of pyrogen removal, sterilization and demineralization in one simple integrated system where prior art processes require three separate processing units. A liquid purification and aeration system is also described in the prior art. Apparatus and method for continuous dehydrogenation and production of sterile water for injection is also mentioned in the prior art. In prior art, Portable intravenous solutions and water for injection apparatus and method is also mentioned. The present embodiment is production of sterile water for injection by using nitrogen purging technique which can increase the life of product. The nitrogen purging technique used in the present invention is displacement purging effective for simple systems. When nitrogen replaces the oxygen in bottle it also serves to preserve the flavor and color of product. By using nitrogen purging technique, the water purification system will become dry, free of

moisture and air.N2 purging is cost effective, energy saving, environmentally friendly way to supply the source of nitrogen.
Object of the Invention
The main object of the invention is to overcome all the associated drawbacks and to produce sterile water for injection using nitrogen purging technique. The object of the present invention is to prepare a novel process for production of sterile water for injection which is free from dissolved oxygen and increase the life of the product and is dry, free of moisture, air and cost effective.
Statement of Invention:
This is innovative process that has been designed and developed by the scientist team of Onyx Biotec Pvt. Ltd. which is useful. This is a compact, reliable, and automatic system which helps to evaporate the dissolved oxygen in the Water. The production of sterile oxygen free water by using nitrogen purging is effective in increasing the life of the product. It is an effective method for preventing oxidation and corrosion. This system is dry, free of moisture and air, cost effective, energy saving, environmentally friendly way to supply the source of nitrogen.
Summary of Invention
The present embodiment is production of oxygen free sterile water by using nitrogen purging process. Firstly purification of raw water stream is carried out by using sand and carbon filtration membrane which strain out colloidal particles. Then water passes doubly through reverse osmosis plant. Water comes in contact with cation and anion exchange resins and demineralization is carried out. Water passes through ultrafiltration

membrane followed by multicolumn distillation membrane. In final step, water for injection is prepared by using nitrogen purging to ensure the water free from the dissolved oxygen.

A Brief description of the accompanying drawing:-
Process Flow Chart For W.F.I
A complete understanding of the present invention may be by reference to the following detailed description which taken in connection with the accompanying drawings, wherein
Fig 1 is the schematic representation of the process for production of oxygen free sterile water for injection using nitrogen purging method.
Figur removed:-
Detailed description of the invention with reference to drawing
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment.
Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or matter.
The present invention is a process for production of oxygen free sterile water for injection. In this invention, Nitrogen purging technique is used for production of sterile oxygen free water for injection.The pharmaceutical and bio-pharmaceutical industries demand high purity water systems that are reliable and capable of consistently providing the required water for Injection (WFI) to meet the established standards of purity. Water for injection is typically stored in a continuously circulating system maintained at an elevated temperature (a temperature of 80-85° C). The circulation of the purified water, under conditions that provide turbulent flow, maintains the elevated temperature uniformly throughout the system. These operating conditions prevent microbial growth and ensure that the water meets the specifications given in the US Pharmacopeia. Nitrogen purging is an efficient, effective method for preventing oxidation and corrosion. This system is dry, free of moisture and air, Use of a nitrogen generator to produce the necessary levels of nitrogen gas is a cost effective, energy saving, environmentally friendly way to supply this resource
USP (United states pharmacopoeia) is a sterile, nonpyrogenic preparation of water for injection which contains no bacteriostat, antimicrobial agent or added buffer and is supplied only in single dose containers to dilute or dissolve drugs for injection.WFI is defined as USP 26 as water purified by distillation or reverse osmosis that contains not more than 0.25 USP Endotoxin Units (EU) per ml. The USP has set the endotoxin limit for WFI at 0.25 EU/mL due to a concern that there might be an additive effect of the low level pyrogens in a drug product and its vehicle (WFI).
The process for production of oxygen free sterile water using nitrogen purging technique is described as follows. Purification of raw water stream is carried out in the first step by using sand and carbon filtration membrane which strain out colloidal particles such as fine sand, anthracite, earth particles or filter fabric. Activated sand filters and carbon filters are used for removing free chlorine, phenol, taste and odor as well as reduction COD/BOD.(Chemical oxygen demand /Biochemical oxygen demand) After this step, water passes doubly through reverse osmosis plant against the concentration gradient, from lower concentration to higher concentration and is stored in water storage tank. Then water passes through mix bed membrane where a single column of Cation and Anion resin material mixed intimately together. Water comes in contact with these resins and subjected to number of demineralising stages. Mixed bed demineralizers are regenerated with acid and alkali but the ion exchange resins must be separated and superimposed layers are thus formed into which the acid and alkali solutions and rinse water are introduced through specially designed spreaders. After regeneration the two resins are remixed with compressed
air. Then water is stored in purified water storage tank. After this water passes through ultrafiltration process which is useful for removal of particulates, microorganisms and also pyrogens. In this technique, very fine particles or other suspended matters, with a particle size in the range of 0.005 to 0.1 microns, are separated from a liquid. It is capable of removing salts, proteins and other impurities within its range. In ultrafiltration, water is forced through a semi-permeable membrane and the pores in that membrane effectively reject dissolved ions, salts and organic compounds.Ultrafiltration membranes have a nominal pore size of 0.0025 to 0.1 microns. After ultrafiltration water passes through multicolumn distillation membrane. It is a perfect method for production of sterile water for injection used for its economy, low maintenance and low operation costs. Distillation removes bacterial endotoxin.
After the distillation process, water is collected in water for injection storage tank designed to withstand pressure as well as vacuum. Therefore it can be steam sterilized. Insulation with SS welded sheeting and jacket provided on the tank will minimize heat loss. All the surfaces coming in contact with WFI are made of SS 316/316L quality. In water for injection storage tank, nitrogen purging is done by using nitrogen generated from the nitrogen plant. Nitrogen purging is done to ensure the water free from the dissolved Oxygen. Nitrogen helps to evaporate the dissolved oxygen in the Water. The quantity of dissolved oxygen is checked by the oxygen meter. This oxygen meter ensures us the complete freedom from it after purging the full concentration of the Nitrogen. This sterile water is free from the dissolved oxygen present in it. Nitrogen generators employ a simple pressure swing adsorption or membrane technology to isolate nitrogen from the air.
Nitrogen gas can be produced on-site and on-demand with a generator, therefore saving storage and transportation costs of high pressure nitrogen gas cylinders. After nitrogen purging process, sterile water is stored in batch manufacturing tank which is free from dissolved oxygen. Water for injection is stored in a continuously circulating system maintained at an elevated temperature (80-85° C). The circulation of the purified water, under conditions that provide turbulent flow, maintains the elevated temperature uniformly throughout the system.
The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention; which is defined by the scope of the following claims.

Claims
I/We claim,
1. A process for production of sterile oxygen free water for injection
substantially free of pyrogens and microorganisms comprising the
steps of;
a) providing a raw water stream to be purified;
b) removing colloidal particles by using filtration membrane;
c) removing dissolved solids, ions, minerals, metals from said water by double reverse osmosis;
d) demineralising cation and anion exchange resins by using mixed bed filtration membrane;
e) removing microorganisms, particulates and pyrogens by using ultrafiltration membrane;
f) removing bacterial endotoxin by using multicolumn distillation membrane;
g) evaporating dissolved oxygen in the water by nitrogen purging.
2. Sterile water for injection substantially free of pyrogens and
microorganisms formed by process as claimed in claim 1 comprising
the steps of
a) purifying raw water stream using filtration membrane;
b) removing some ions, solids by reverse osmosis membrane;
c) deionizing cation & anion exchange resins and removing microorganisms by using ultrafiltration membrane;
d) preventing air contamination by using multicolumn distillation membrane;
e) making water free from dissolved oxygen using nitrogen purging

3. A process for preparation of sterile oxygen free water for injection as claimed in claim 1 wherein the sterile water is passed sequentially through steps (a), (b), (c), (d), (e), (f) and (g).
4. A process for producing sterile oxygen free water for injection substantially free of pyrogens and microorganisms as claimed in claim 1 where the said sand and carbon filtration membrane carries out removal of colloidal particles such as fine sand, anthracite, earth particles or filter fabric, free chlorine, phenol, taste and odour as well as reducing COD/BOD.
5. A process for production of sterile oxygen free water for injection substantially free of pyrogens and microorganisms as claimed in claim 1 where the said reverse osmosis is carried out using semi permeable membrane by applying osmotic pressure.
6. A process for production of sterile oxygen free water for injection substantially free of pyrogens and microorganisms as claimed in claim 1 where the said mixed bed demineralizers are formed by mixing cation and anion exchange resins.
7. A process for production of sterile oxygen free water for injection substantially free of pyrogens and microorganisms as claimed in claim 1 where the said ultrafiltration membrane carries out removal of particles in the range of 0.005 to 0.1 microns.

8. A process for production of sterile oxygen free water for injection substantially free of pyrogens and microorganisms as claimed in claim 1 by using the said multicolumn filtration membrane air contamination is prevented.
9. A process for production of sterile oxygen free water for injection substantially free of pyrogens and microorganisms as claimed in claim 1 in which the quantity of dissolved oxygen in nitrogen purging is checked by oxygen meter.