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xxx xxx xxx In accordance with the present invention the problem can be solved by providing iron (III) carbohydrate complexes on the basis of the oxidation products of maltodextrins. Therefore, an object of the present invention are water soluble iron carbohydrate complexes which are obtainable from an aqueous solution of an iron (III) salt and an aqueous solution of the oxidation product of one or more maltodextrins, using an aqueous hypochlorite solution at an alkaline pH-value of e.g. 8 to 12 where, when one maltodextrin is applied, its dextrose equivalent lies between 5 and 20, and when a mixture of several maltodextrins is applied, the dextrose equivalent of the mixture lies between 5 and 20 and the dextrose equivalent of each individual maltodextrin contained in the mixture lies between 2 and A further object of the present invention is a process for producing the iron carbohydrate complexes according to the invention wherein one or more maltodextrins are oxidized in an aqueous solution at an alkaline pH-value of e.g. 8 to 12 using an aqueous hypochlorite solution and reacting the obtained solution with an aqueous solution of an iron (III) salt where, when one maltodextrin is applied, its dextrose equivalent lies between 5 and 20, and when a mixture of several maltodextrins is applied, the dextrose equivalent of the mixture lies between 5 and 20 and the dextrose equivalent of each individual maltodextrin contained in the mixture lies between 2 and

40."

(emphasis supplied)

71. As rightly contended by the Defendants, there is an admission by Vifor that use of iron carbohydrate complexes is known and a water- soluble iron (III) hydroxide sucrose complex is a frequently and successfully used preparation. It is stated that the problem to be solved by the present invention is to provide an iron preparation which is especially to be applied parenterally and can be easily sterilized as the known parenterally applicable preparations on the basis of sucrose and dextran were only stable at temperatures up to 100oC, which made sterilization difficult. It is categorically asseverated in the complete specification that present invention is a process for producing iron carbohydrate complexes wherein one or more 'maltodextrins' are oxidized in an aqueous solution at an alkaline 'pH' using 'aqueous hypochlorite solution' and further that when one maltodextrin is applied, the DE value is between 5 and 20 and when mixture of several maltodextrin is applied, the DE value of the mixture lies between 5 and 20 and the DE value of each individual maltodextrin contained in the mixture lies between 2 and 40. Given the admission of Vifor in the complete specification that iron carbohydrate complexes were already known, the only prima facie conclusion that this Court can reach is that the purported invention resides in preparing iron carbohydrate complexes with maltodextrin as the starting material and/or the step of oxidation using the specified oxidizing agent i.e. aqueous hypochlorite solution. In fact, what Vifor overlooks in making the submission that the process is inconsequential, is that the characteristic properties that it claims in FCM, distinguished from the prior art, are a direct result of the process used by Vifor, an admission that it makes during the prosecution of the patent application and is glaringly evident in the complete specification. Therefore, the scope of Claim 1 of IN'536 is limited to a product obtained through a specific process feature identified therein and cannot cover any and all processes that may be used by a third party to produce FCM and it is thus held that Claim 1 is a product-by- process claim and not a pure product claim.

81. Schematically and diagrammatically, the two processes are depicted as follows:

MALTODEXTRIN BASED FCM (IN'536) STARCH BASED FCM (VIRCHOW)

82. A reading of Claim-1 in IN'536 reveals that it claims water-soluble iron carbohydrate complexes obtainable from aqueous solution of iron (III) salt and aqueous solution of oxidation product of one or more maltodextrins using an aqueous hypochlorite solution at an alkaline pH. The process starts from maltodextrin as a starting material with DE value 2-20, which is then oxidized in the presence of sodium hypochlorite to obtain oxidized maltodextrin, which then reacts with iron (III) salt to obtain a maltodextrin-based iron complex. Prima facie the essence of Vifor's patent is a maltodextrin-based iron complex. In fact, it is Vifor's stated case that its product FCM is different from prior art which includes dextrin-based complexes since Vifor uses 'maltodextrin as the starting material' instead of any other carbohydrate. This position was clearly adopted by Vifor before the Controller of Patents during prosecution of IN'536. The essential features of IN'536 are: (a) iron (III) core;

89. From a reading of the aforesaid research publications/articles, two conclusions prima facie emerge: (a) maltodextrin cannot have a DE value greater than 20; and (b) partial hydrolysis of starch to different extents of depolymerization yields different commercially useful products, characterized by their DE value and maltodextrins are formed with a DE value lower than 20 while those with DE value greater than 20 are glucose syrups. Pertinently, in the rejoinder arguments, submitted to the Court through a written note, it is admitted by Vifor that maltodextrin with DE value above 20 is a glucose syrup. Holistically and cumulatively seen, the stand of the Defendants that the DE value of the product of starch hydrolysis being 25-27 is an indicator that the process does not use maltodextrin is prima facie correct and that of Vifor to the contrary cannot be accepted. It would be relevant at this stage to reiterate the stand of Vifor before the Controller of Patent during the prosecution of IN'536 that "the essence of the present invention is that by appropriately selecting suitable maltodextrins having specific dextrose equivalent as defined in the claims".