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21. The respondents say that the claims as claimed in Patent no. IN 434424 cannot and could not be granted as the ferric carboxymaltose complex/ composition claimed in 1-6 of the claim of the said patent is not novel and is well known to the public and also from claim 4 of the main patent no. IN 370845. He submits that the modification contemplated in the Patent No. IN 434424 over the main patent 370845 is only in the oxidation steps of maltodextrin. Oxidation of maltodextrin was carried out by using citric acid in 370845, the said oxidation in 434424 is carried by using ozone gas, which is a colourable imitation based on common general knowledge.

25. The respondent further submits that the reaction of FeCls and NaOH although is not supported anywhere in the specification, the said reaction to produce ferric hydroxide is even known to elementary chemistry students. In the impugned claim 1 of patent 370845 Petitioner has claimed to use only a new cross-linking agent for maltodextrin viz. citric acid. I say that selection of citric acid as cross- linking agent of maltodextrin is devoid of any uniqueness, as cross- linkage of various starches including maltodextrin is very well known long before the impugned invention was conceptualized sometime in 2017 inter alia at least from the article Thermal Crosslinking of Maltodextrin and Citric Acid. Methodology to Control the Polycondensation Reaction under Processing Conditions published in Polymers & Polymer Composites, Vol. 24, No. 8, 2016 and the reaction scheme of claim 1 of 370845 of oxidizing maltodextrin with citric acid and reacting the oxidized maltodextrin with ferric hydroxide to produce ferric carboxymaltose, is not workable as citric acid is in fact a reducing agent and not an oxidizing agent as falsely claimed, and therefore no oxidation of maltodextrin is possible.

WO2016151367 describes a process for preparation of iron (III) carboxymaltose complex which include reacting aqueous solution of iron (III) salt with aqueous solution of oxidation product of at least one maltodextrin. The oxidation of maltodextrin is carried out in presence of catalyst and phase transfer catalyst in alkaline medium.

The processes in the art require catalysts, phase transfer catalysts for performing oxidation of maltodextrin which add to the manufacturing cost. The use of sodium hypochlorite as the oxidizing agent lead to formation of undesired chlorinated by products. The processes in the art thus suffer from the drawbacks of formation of inorganic impurities such as metal bromides, chlorides and carbonates which impact the yield and purity of iron(II)-carboxymaltose.

US7612109, US20120214986A1, WO2016151367A, US20210155651A1 disclosed a process for water-soluble ferric carbohydrate complexes obtained by oxidation of maltodextrin followed by coupling with iron (III) chloride. Maltodextrin contained in the mixture lies between 2 and 40 dextrose equivalents which resulted in water soluble iron carbohydrate complex having an average molecular weight of 80,000 to 400,000 Daltons.

It is evident from published methods that the ferric carbohydrate complexes prepared from dextrin having a varying dextrose equivalents unit. Broadly, it involved two steps or in situ one step processes where both require the oxidation of maltodextrin and coupling with iron salts. The oxidation methods Include sodium hypochlorite with without sodium bromide, hydrogen peroxide, sodium hypochlorite + hydrogen peroxide, sodium tungstate etc. In the second stage, iron salts were used for coupling to yield ferric carboxymaltose. The maltodextrins were used with varying dextrose units ranging from 5 to 20 DE which gave varying molecular weights of ferric carboxymaltose. All the processes in the previous art suffer from the following drawbacks, formation of iron carbohydrate complexes with inconsistent average molecular weight and iron content, formation of undesired chlorinated by-products such as chlorides, metal bromides, and carbonates. Thus, generating a large quantity of chemical waste which is difficult to treat and hence, unsuitable for the commercial scale. The dextrin with varying dextrose equivalents used in the reported methods can be obtained according to the literature methods. However, the methods used various combinations of dextrin's from 5 to 20 DE which significantly affect the average molecular weight of the ferric carboxymaltose.