DESC:AN IMPROVED PROCESS FOR THE PREPARATION OF SARTAN, FREE OF GENOTOXIC AZIDE IMPURITIES Field of Invention: The invention directs to a method for synthesis and purification of Losartan of the Formula (1), its intermediates, pharmaceutically acceptable salts and solvates thereof; also herein described are the compositions, comprising of substantially pure Losartan free-base or salts thereof free of the genotoxic azide, amine and carcinogenic impurities. Formula 1 Background of the Invention: Losartan is an angiotensin II receptor blocker (ARB) indicated for treatment of hypertension; MERCK SHARP AND DOHME CORP. marketed losartan potassium as COZAAR and a combination of losartan with hydrochlorothiazide a diuretic drug as HYZAAR. Losartan potassium is chemically described as 2-butyl-4-chloro-1-[p-(o-1H-tetrazol-5-ylphenyl)benzyl]imidazole-5-methanol monopotassium salt. Its empirical Formula is C22H22ClKN6O, and its structural Formula given as Formula 2: Formula 2 The potassium salt of Losartan is a white to off-white free-flowing crystalline powder with a molecular weight of 461.01. It is freely soluble in water, soluble in alcohols and slightly soluble in common organic solvents, such as acetonitrile and methyl ethyl ketone. Oxidation of the 5-hydroxymethyl group on the imidazole ring results in the active metabolite of Losartan. FDA in recent times have observed multiple batches of various sartans such as losartan in the market, contaminated with genotoxic azide impurities, and carcinogens belonging to the N-nitrosamines family (NDMA, NDEA and NMBA). Various experimental data has proven the risks of the presence of nitrosamines, and their carcinogenic nature effects the liver, kidneys, lungs and blood vessels; and articles by EDQM have confirmed the genotoxic nature of azide, based on the positive test in a bacterial mutagenicity (Ames) test. Losartan’s genotoxic azide impurities are undesired products formed during the tetrazole ring formation. As sartans require daily administration, the presence of azido impurities beyond a certain limit according to TTC (Threshold of Toxicological Concern) are critical to the patients who are on a daily drug regime, thus such potential genotoxic structural moieties need to be suppressed during synthesis. A generalized process for the synthesis of Losartan and its potassium salt is as given below: WO 2004062568 discloses the Losartan molecule transformed to the azide-derivative followed by reduction to its corresponding amine as disclosed below in Scheme 1. However, the patent application does not relate to synthesis of losartan or its salts. Scheme 1 Organic Process Research & Development, 2012 16(12), 2025–2030, gives us an understanding that the use of the mole ratios of trimethylamine hydrochloride and sodium azide during the tetrazole ring formation have significant impact on the reaction rate and impurity profile by reducing the inorganic azide impurities such as hydrazoic acid. The study also found that at the stoichiometric ratio where one impurity, losartan azide (Formula A) due to traces of free hydrochloric acid, formed >1%, is proved difficult to remove. The process disclosed also constructs the tetrazole ring by following the widely practiced protocol, by mildly refluxing the mixture of cyano alcohol and sodium azide with triethylamine hydrochloride - generated in situ, in toluene and NMP (N-Methyl-2-pyrrolidone). The drawback of which is the additional formation of the carcinogenic nitrosamines impurities. The article above covers a process for the synthesis of the impurities and a process that involves the use of sodium nitrite and hydrochloric acid mixture. However, the process is cumbersome and with higher amount of nitrosamine impurities in the final product. The article fails to describe an efficient method to suppress the impurities during production on an industrial scale. Our present invention addresses this issue at hand by providing an improved process that is efficient, industrially scalable and economical. Scheme 2 There are various processes in the art that involve the use of different azide reagents during the tetrazole-formation; WO 2005014602 discloses the preparation of Losartan of the Formula (I) that comprises of reaction of the cyano alcohol with diethyl aluminium azide in the presence of triethyl aluminium. The use of diethyl aluminium azide and triethyl aluminium needs special attention like very anhydrous conditions, reactions are to be performed under nitrogen or argon and transferring of triethyl aluminium from the containers needs anhydrous systems as they are known to be combustible at room temperature in the presence of air, etc. The present invention overcomes this disadvantage by avoiding the use of reagents such as diethyl aluminium azide and triethyl aluminium. In addition, the process involves a purification process that deals with the possible undesired azide products; thus increases the efficiency of the process by avoiding additional special and anhydrous conditions and thus provides for a highly commercially scalable and economical process. EP 0578125 discloses another method for the preparation of Losartan wherein, tetrazole-forming agent such as Trioctadecyl or Trioctyl tin azide reacts with the cyano alcohol to yield tri-n-octyl tetrazole derivative, which when treated with nitrous acid gave Losartan of the Formula (I) in 91.4% yield. The process although addressed the human related safety concerns still involve the use and handling of heavy metal that results in Trioctadecyl and Trioctyl tin azide leading to presence of tin contaminants. Thus, close monitoring of the process by pharmacopoeia methods are required including trace levels of genotoxic and carcinogenic impurities in the final product. The present invention overcomes this disadvantage by providing an improved process for the preparation of losartan that does not involve the tetrazole-forming agent such as Trioctadecyl or Trioctyl tin azide to yield heavy metals and a purification process to address the possible undesired azide impurities formation. Similarly as stated above, the process disclosed in US Patent US 7915425 involves the use and handling of heavy metal that resulted in the tin residues from the reagent tributyl tin chloride that led to the possible presence of tin contaminants in the final product. The present invention overcomes the disadvantage by providing an improved process for the preparation of losartan that does not involve the tetrazole-forming agent such as tributyl tin chloride and has proven to yield a product with controlled levels of genotoxic azido impurities and cariogenic impurities. J. Med. Chem. 1991, 34, 2525-2547 and Merck/Dupont patents also disclose various processes, which involve the use of trimethyl tin azide or tri alkyl tin azides for the formation of trityl losartan, wherein the compound is further detritylated to yield Losartan. The present invention relates to process for the preparation of losartan and the said process differs from the process disclosed in the former article in light of using trimethyl tin azide or tri alkyl tin azides for the formation of trityl losartan. US 7923566 discloses the invention relates to an improved process for the preparation of Losartan. The said process comprises reacting 2-n-butyl-4-chloro-5-formyl imidazole with 2-(4-bromomethyl) benzonitrile in the presence of a phase transfer catalyst and an alkali, and reducing the resulting cyano aldehyde to produce a cyano alcohol which is further reacted with sodium azide and triethyl amine hydrochloride in N-methyl pyrrolidinone to produce Losartan. This process has shown to be cumbersome and the degradant of NMP (N-Methyl-2-pyrrolidone) leads to formation of the corresponding Nitrosamine, NMBA. All the processes described above uses metal azides for the preparation of tetrazole derivative that are environmentally hazardous chemicals and their disposals are not only cause always problems but also need special methods for safe disposal. It has also been observed that during the formation losartan, in particular the synthesis of tetrazole ring and various genotoxic azido impurities and carcinogenic impurities such as N-Nitrosodimethylamine (NDMA), N-Nitroso-N-methyl-4-aminobutyric acid (NMBA) and N-nitroso-diethylamine (NDEA) are formed and in light of the daily dosage regimes the risk of adverse effects are inevitable. Hence, there is a continuous urge to develop Sartans and their salts as a product with controlled, low or even absence of genotoxic azido and carcinogenic compounds. The inventors of the present invention speculated the improved process for losartan that provides controlling the azido genotoxins and carcinogens belonging to the N-nitrosamines family. Thus, the present invention overcomes the above issues by providing an improved process for the preparation of losartan that involves the use of Triphenylphosphine (TPP) at various steps of the process to help neutralize the harmful impurities and improve isolation, thus increases the efficiency of the process in terms of time and easing the commercial scalability. It also leads to a continuous process wherein there is less chance to lead to the formation of the genotoxic azido and cariogenic impurities. The present invention minimizes multiple sources of impurities at various stages via the isolation of intermediates and by purification, this has led to an added advantage of mass production within shorter duration of time while maintaining improved quality and enhanced yield. Thus, the synthesis and purification process found to be commercially scalable with high level of consistency. Wherein the said azido genotoxins and carcinogens in the final product are surprisingly within the limits or is undetectable by any known instruments. Even more the final product has found to be stable over a long shelf life. Objectives of the Invention: The main objective of the present invention is to provide an improved process for the preparation and purification of Losartan (Formula 1), its pharmaceutically acceptable salts and solvates thereof, to overcome the formation of organic genotoxic azide impurities such as Losartan azides (Formula A, B, C, D, and E) and its respective amines. Another objective of the present invention is to provide an improved process for the preparation of Losartan (Formula 1) and its salts thereof with high purity. Still another object of the present invention is to provide an improved, economical and safe method of synthesis of Losartan (Formula 1), wherein the azides impurities and in particular the genotoxic organic azides, such as alkyl azides are converted/reduced in the presence of TPP. Isolating the inert impurities to controls alkyl azides to the trace levels (below 10 ppm) or below the level of detection (85%). Step 2b: Preparation of (1- ((2'- (1H-tetrazol-5-yl) biphenyl-4-yl) methyl) -2 - butyl -4 - chloro-1H- imidazol-5-yl)methanol [Losartan] of the formula I: To a stirred solution of Toluene (1 volume) and triethylamine hydrochloride (TEA HCl) (2.76 mole eq.), add Formula 1b (1 mole eq.) of step 1, and stirred for 10-15 minutes at 25-35°C. NMP (N-Methyl-2-pyrrolidone) (0.1w/w) was charged and stirred for 5-10 minutes, Sodium azide (2.41 mole eq.) and stirred for 10-15 minutes at 25-35°C. The reaction mass was heated to 92±2°C and maintained for 48-60 hours. After completion of reaction the reaction mixture is cooled to 55-65°C and added purified water (3 volumes), sodium hydroxide solution (5.23 mole eq.), was added and heated to 55-65°C. Bottom azide aq. layer separation followed by addition of purified water (3 volumes) and the lower product layer was isolated and cooled to 25-35°C. After extraction of aq. layer with toluene twice, charged with purified water (3 volumes) and Triphenylphosphine (0.014 mole eq.) and SMBS (0.15 mole eq. (0.075w/w)). The reaction mass was heated to 70-75°C and maintained for 2-3 hours. Activated carbon was charged and stirred for 20-30 minutes and filtered over a hyflo bed. The bed was washed with purified water (1 volume) at 70-75°C and resultant filtrate was isolated and cooled to 25-35°C. Ethyl acetate was added into reaction mass and adjusted the mass pH to 4.0-6.0 with sulfuric acid solution. The precipitated mass was cooled to 10-15°C and filtered. The filtered material is purified in acetone (2 volumes) and dried at 65-75°C for 6-8 hours, to yield Losartan - Formula 1. (Yield: >85%). Example 2: Preparation of Losartan Potassium (Formula 2): To a stirred solution of Losartan - Formula 1 (1 mole eq.), (Example 1 step 2) in methanol (3.5 - 4 volumes), pH was adjusted to 9.0-9.5 with potassium hydroxide (1.15-1.2 mole eq.) and stirred for 30-60 minutes at 25-35°C. The reaction mixture is charged with Triphenylphosphine (0.014 mole eq.) and temperature raised to 40-45°C maintained for 2-4 hours. Charged with Activated carbon and the temperature was maintained at 40-45°C for 1-2 hour, the reaction mixture was filtered on hyflo bed followed by methanol wash. The clarified solution was concentrated by vacuum to remove most of methanol at a temperature below 60°C under reduced pressure. There after co-distillation with acetone (0.5 V) thrice followed by addition of acetone (3.5 - 4 volumes) and maintain at reflux temperature 55-60°C followed by cooling to 25-35°C and further the mass is cooled and maintained at 0-5°C for 1-2 hours under nitrogen atmosphere. The solid was filtered washed with acetone and dried at 60-65°C for 6-8 hours to yield Losartan Potassium of the Formula 2. (%Yield: > 88.07%). Example 3: The standard reference for Losartan azido impurities - Formula A, B, C, D, and E, are synthesized according to example 1a WO 2004062568: Example 3a: Preparation of 5-[4'-[(5-(Azidomethyl)-2-butyl-4-chloro-1H-imidazol-1-yl)methyl]-[1,1'-biphenyl]-2-yl]-1H-tetrazole - Formula A To a stirred suspension of Losartan (Formula 1) (0.423 g, 1.00 mmol) and diphenylphosphoryl azide (0.259 ml, 1.20 mmol) in tetrahydrofuran (8 ml) was added DBU (1,8-Diazabicyclo[5.4.0]undec-7-ene) (0.329 ml, 2.20 mmol). After reaction maintenance for overnight and suitable work up process followed by purification in column chromatography to yield Formula A. Example 3b: Preparation of 4'-((5-(azidomethyl)-2-butyl-4-chloro-1H-imidazol-1-yl)methyl)-[1,1'-biphenyl]-2-carbonitrile - Formula B: 4'-((5-(azidomethyl)-2-butyl-4-chloro-1H-imidazol-1-yl)methyl)-[1,1'-biphenyl]-2-carbonitrile Impurity or compound of Formula B may be synthesized by the process as described in Example 3a, by replacing Losartan (Formula 1) with 4'-((2-butyl-4-chloro-5-(hydroxymethyl)-1H-imidazol-1-yl)methyl)-[1,1'-biphenyl]-2-carbonitrile (compound of formula 1b). Example 3c: Preparation of 5-(4'-(azidomethyl)-[1,1'-biphenyl]-2yl)-1H-tetrazole - Formula C: 5-(4'-(azidomethyl)-[1,1'-biphenyl]-2yl)-1H-tetrazole Impurity or compound of Formula C may be synthesized by the process as described in Example 3a, by replacing Losartan (Formula 1) with 5-(4'-(bromomethyl)-[1,1'-biphenyl]-2-yl)-1H-tetrazole Example 3d: Preparation of 4'-(azidomethyl)-[1,1'-biphenyl]-2-carbonitrile - Formula D: 4'-(azidomethyl)-[1,1'-biphenyl]-2-carbonitrile Impurity or compound of Formula D may be synthesized by the process as described in Example 3a, by replacing Losartan (Formula 1) with 4'-(bromomethyl)-[1,1'-biphenyl]-2-carbonitrile (Bromo-OTBN) . Example 3e: Preparation of 4-(azidomethyl)-2-butyl-5-chloro-1H-imidazole - Formula E: 4-(azidomethyl)-2-butyl-5-chloro-1H-imidazole Impurity or compound of Formula E may be synthesized by the process as described in Example 3a, by replacing Losartan (Formula 1) with 2-Butyl-4-chloro-5-formylimidazole (BCFI). ANALYSIS OF GENOTOXIC ORGANIC AZIDES SUCH AS ALKYL AZIDES: To summarize, we have used LC-MS/MS as an analytical method for validating and estimating Genotoxic Organic Azides content in Losartan (Potassium), wherein a combinations of LC columns [Hypersil BDS and XTERRA RP] and MS Probes [APCI (Positive) and ESI (Positive/Negative)] maybe used to detect the impurities. BATCH ANALYSIS RESULTS: Batches Data for synthesis of Losartan freebase (Formula 1) Batch Yield (%) Not more than 10 ppm Not more than 0.3% Formula A (ppm) Formula B (ppm) Formula C (ppm) Formula D (ppm) Formula E (ppm) Total Impurities 1 85.33 ND ND ND ND ND 0.05 2 85.11 ND ND ND ND ND 0.05 3 85.56 ND ND ND ND ND 0.05 *ND: Not Detected Batches Data for synthesis of Losartan potassium (Formula 2) Batch Yield (%) Not more than 10 ppm Not more than 2.0% Formula A (ppm) Formula B (ppm) Formula C (ppm) Formula D (ppm) Formula E (ppm) Total Impurities 1 88.07 ND ND ND ND ND 0.25 2 87.15 ND ND ND ND ND 0.23 3 87.71 ND ND ND ND ND 0.26 *ND: Not Detected From the foregoing embodiments of the present invention described above are well suited to provide the advantages set forth. Since many possible embodiments maybe made of the various features of this invention, all without departing from the scope of the invention; it is to be understood that all matter herein before set forth or shown in the description and synthetic schemes is to be interpreted as illustrative and that in certain instances some of the features may be used without a corresponding use of other features, all without departing from the scope of the invention. Dated this: 27th day of October, 2022. Signature: Name: Mr. Srinivasa Reddy Madduri Patent Agent Reg. No.: IN/PA-1268 GRANULES INDIA LIMITED My Home Hub, 2nd Floor, 3rd Block, Madhapur, Hyderabad, Telangana, INDIA-500 081 ,CLAIMS:We Claim: 1. An improved process for the preparation of Losartan or pharmaceutically acceptable salt thereof with substantially free of azide or amine impurities comprising: a) bromination of 4'-methylbiphenyl-2-carbonitrile in the presence of brominating agent selected from dibromo dimethyl hydantoin (DBDMH) to give 4'-(bromomethyl)biphenyl-2-carbonitrile; b) condensation of 4'-(bromomethyl)biphenyl-2-carbonitrile with (2-Butyl-4-Chloro-5-Formyl-1H-Imidazole in presence of a base and a phase transfer catalyst to give 4'-((2-butyl-4-chloro-5-formyl-1H-imidazol-1-yl)methyl)biphenyl-2-carbonitrile; c) reducing 4'-((2-butyl-4-chloro-5-formyl-1H-imidazol-1-yl)methyl)biphenyl-2-carbonitrile in the presence of sodium borohydride to give 4'-((2-butyl-4-chloro-5-(hydroxymethyl)-1H-imidazol-1-yl)methyl)biphenyl-2-carbonitrile; d) converting 4'-((2-butyl-4-chloro-5-(hydroxymethyl)-1H-imidazol-1-yl)methyl)biphenyl-2-carbonitrile into losartan by treating with sodium azide to give crude losartan; and e) treating crude losartan with triphenylphosphine to give pure Losartan or it’s salt with substantially free of azide or amine impurities. 2. The process as claimed in claim 1, wherein said base in step b) is selected form sodium hydroxide, calcium hydroxide, potassium hydroxide. 3. The process as claimed in claim 1, wherein said phase transfer catalyst in step b) is selected from Tetrabutyl ammonium bromide (TBAB), or Benzyl triethyl ammonium chloride (TEBAC) and Polyethylene Glycol. 4. A process of purifying Losartan or pharmaceutically acceptable salt thereof with substantially free of azide or amine impurities comprising treatment of Losartan with triphenylphosphine. 5. A preparation method of Losartan potassium salt with substantially free of azide or amine impurities comprising reaction of Losartan with potassium hydroxide and treatment of obtained reaction mixture with triphenylphosphine. 6. The process as claimed in claim 5, wherein reaction of Losartan with potassium hydroxide in the presence of alcoholic solvent selected from methanol, ethanol and the like. 7. Losartan or pharmaceutically acceptable salt thereof with substantially free of azide or amine impurities of the following: Formula A: 5-[4'-[(5-(Azidomethyl)-2-butyl-4-chloro-1H-imidazol-1-yl)methyl]-[1,1'-biphenyl]-2-yl]-1H-tetrazole Formula B: 4'-((5-(azidomethyl)-2-butyl-4-chloro-1H-imidazol-1-yl)methyl)-[1,1'-biphenyl]-2-carbonitrile Formula C: 5-(4'-(azidomethyl)-[1,1'-biphenyl]-2yl)-1H-tetrazole Formula D: 4'-(azidomethyl)-[1,1'-biphenyl]-2-carbonitrile Formula E: 4-(azidomethyl)-2-butyl-5-chloro-1H-imidazole Formula F: (1-((2'-(2H-tetrazol-5-yl)-[1,1'-biphenyl]-4-yl) methyl)-2-butyl-4-chloro-1H-imidazol-5-yl) methanamine.