Patenting Lal dant manjan

Analysis of patent claim (US Patent no. US 7, 736,629 B2)

Colgate’s claim is set in the light of the need for an “invention which provides a red-coloured tooth powder having an aesthetic appeal to customers but does not exhibit the harsh abrasiveness found in many conventional red coloured toothpowders”. It must be noted that the composition of Colgate’s invention is largely similar to that of the ordinary ‘lal dant manjan’ Technically, the invention comprises of (a) calcium carbonate of desired size and angularity which imparts mild abrasiveness to dental enamel and (b) highly purified natural red iron oxide of low abrasiveness. In essence, when compared with other oral dentifrices, it is less abrasive. Interestingly, the patent claim compared itself with other oral dentifrices including Dabur India’s ‘lal dant manjan’!! Thus, as I stated earlier, it is incorrect to state, at least at a prima facie level, that ‘lal dant manjan’ per se was patented. The focus should be on whether the modified ‘lal dant manjan’ deserves patent. I shall argue that the grievances are justified and the instant patent should be revoked and application before Indian Patent Office be rejected.

Any invention should satisfy the following:

a)    Novelty

Novelty is of three standards:

Absolute novelty: Any act which makes an invention available to the public, no matter where in the world, before the filing date or priority date forms part of ‘state of the art’. Such acts include written publications, sales, public oral disclosures and public demonstrations or use. Eg. India, UK.

It should be shown that the claimed invention is quantitatively different from what has been disclosed previously; i.e the technical information disclosed by the patent is not already available to the public. In effect, one has to prove that the claimed invention is not traditional knowledge or an aggregation / duplication of known properties of traditionally known components (S. 3(p) of Patents Act). This has to be judged against all the information which is available at the priority date of the invention; irrespective of where the information was released or the form that it was released in. 

Relative novelty: As per this standard, publication and not the use of that invention outside the country in which protection is sought forms part of ‘state of the art’. Eg. US ( 35 U.S.C. 102)

Local novelty: Any public use or publication of the invention before the priority date will not destroy novelty unless the use or the publication occurs in the country. Eg. New Zealand

As I have stated earlier, the composition of modified ‘lal dant manjan’ is largely similar to that of ordinary ‘lal dant manjan’ which is documented. Further, as discussed subsequently, correlation between particle size and abrasiveness which forms the essence of the invention is documented. However, it must not be forgotten that Colgate is not, at least at a prima facie level, trying to patent the well-known ‘lal dant manjan’. Thus, whether the invention is novel or not can be conclusively determined only by a ‘prior art search’. Assuming the novelty of the instant invention, I shall explain the lack of inventive step in it.

b) Inventive step

As per the Windsurfer decision, analysis of inventive step must begin by identifying the inventive concept embodied in the patent. The differences which exist between the cited prior art and the alleged invention must then be identified. Finally, viewed without any knowledge of the alleged invention, those differences must constitute steps which would have been non-obvious to the skilled man. In M/s Bishwanath Prasad Radhey Shyam v. M/s Hindustan Metal Industries (AIR 1982 SC 1444), Supreme Court held as follows: “It is important to bear in mind that in order to be patentable an improvement on something known before or a combination of different matters already known, should be something more than a mere workshop improvement; and must independently satisfy the test of invention or an inventive step.”

As stated earlier, the crux of the instant invention lies in its low abrasiveness which is linked to the particle size of calcium carbonate and red iron oxide. However, this correlation between particle size and abrasiveness is a well-known fact. It was discussed by M.L. Smith in “The Influence of Particle Size, Shape, Aggregation and Harness on the Abrasiveness of Fine Powders”,  J Soc Chem Ind 54:269, 1935 ( This has been mentioned in “Laboratory studies concerning the enamel and dentin abrasion properties of common dentifrice polishing agent” by George K. Stooney and Joseph C. Muhler here ) The author observed that the abrasiveness of calcium carbonate on dentin increased linearly with increasing particle size. In other words, abrasiveness is directly proportional to the particle size. Considering this fact, the difference which exists between the cited prior art and the instant invention viz., difference in abrasiveness, is a “workshop improvement” and obvious to a person skilled in the art (PHOSITA) resulting in lack of inventive step.  Considering this aspect, the instant patent should be opposed in USPTO and the patent application before Indian Patent Office be rejected without any further delay.