“A method for producing an aqueous solution of an active ingredient of phenolic nature which is paracetamol susceptible to oxidation, while preserving for an extended period characterized in that the solution is deoxygenated by bubbling with at least one inert gas and/or placing the solution under vacuum until the oxygen content is below 2 ppm, in that the afore-mentioned aqueous solution of an active ingredient, is optionally topped with an inert gas atmosphere and placed in a closed recipient in which the prevailing pressure is of 65, 000 Pa maximum, in that the oxygen content of the aqueous solution is below or equal to 2 ppm and in that the effect of deoxygenation of the solution is completed by addition of an antioxidant and a hydroxypolycarboxylic acid.”
Correct me if I’m wrong: but isn’t the principle of preventing oxidative degradation with the help of an inert gas obvious and well known?
If so, truly an inert patent, one might say?
The principle may be obvious but the claim is a “method for preparation.” I have not had the opportunity to see the file wrapper for this patent but it seems that the claim is very specific approach-which is why it has been granted.
The inventor in all probability deserves the patent for his method.
the method is based on the “principle” enunciated? and the principle stated in the claim is:
“A method for producing an aqueous solution of an active ingredient of phenolic nature which is paracetamol susceptible to oxidation, while preserving for an extended period characterized in that the solution is deoxygenated by bubbling with at least one inert gas…”
There is “and/or” after “gas”…which means the part extracted above stands on its own as well….
The and/or clarifies the de-oxygenation that can be done either by bubbling with at least one gas or by placing under vacuum -any of which is performed ‘until’ oxy content is <2ppm.
The qualifier is ‘until.’
Then it states that the aq. sol. ‘may’ be topped with an inert gas- and placed in a recipient where the pressure is 65000 Pa.
So key elements are:
<2 ppm oxy
pressure-max-65000 Pa.
Note that the anti-ox + is an optional step.
The inventor has given specific examples (see the tables in the spec.) where stability of the solution is shown with values of the pressure and oxygen claimed.
Also the application cites a previous patent by the inventors where the oxy content and pressure requirements were different.
Tks for this extremely useful construction. I am passing it onto a zealous drug control officer (already featured on this blog earlier), who is interested in opposing this patent in his private capacity.
So really, the patentee could pretty much claim any method of using inert gas in a solution until the oxygen content is below 2 ppm?? the latter half, as you rightly note is nothing more than “optional” (..is optionally topped)…so we can’t read that as a necessary qualifier to the first part of the claim.
Phenolic active principles are generally susceptible to oxidation in an aqueous solvent. Thus bubbling with inert gas is a common procedure in pharma to prepare a formulation that is stable to oxidation.
I beg to differ with anon as he pointed out that “below 2 ppm” is a key attribute. Well, below 2 ppm is a standard limit which is considered for making the formulation deoxygenated. There are various other parameters like temperature, pH which could motivate the person skilled in the art considering the drawbacks in prior art.
Given patent has squeezed out through non-obviousness considering the particulars of 65000 pascal of pressure, provided that claims 5 to 10 make the invention unique and I guess those are the things considered by the learned examiner.
May be the novelty aspect of such patent can also be reviewed.
A reader writes in stating:
“Dear Shamnad
There might be some novelty / inventive step in achieving the “the effect of deoxygenation of the solution by addition of an antioxidant and a hydroxypolycarboxylic acid” .
I reply as below:
“But isn’t this the optional part that comes up in the latter half of the claim Alok? In other words, the first part of the claim stands independently and covers any use of inert gases to get the oxygen levels to 2 ppm.
Tks—SB”
Another reader notes as below:
“Dear Shamnad,
It appears that invention resides in the many limitations-
I. only relates to aqueous solution of an active ingredient of phenolic
nature which is paracetamol
II. bubbling with at least one inert gas and/or placing the solution
under vacuum until the oxygen content is below 2 ppm
III. placed in a closed recipient in which the prevailing pressure is of
65, 000 Pa maximum
IV. in that the oxygen content of the aqueous solution is below or equal
to 2 ppm
V. and in that the effect of deoxygenation of the solution is completed
by addition of an antioxidant and a hydroxypolycarboxylic acid
It provides an specific selection invention to the inventor, however, such
invention may be circumvented easily by overcoming one or more limitations,
subject to the condition, if the intended purpose of the invention is
achieved.
Please correct me, if my interpretation is…..”
I reply as below:
“Thanks Dr,
The claim stands alone on I + II. III etc are optional as the patent itself states.
And you’re right that it can be easily circumvented. But the cover of I + II itself appears broad, obvious and nothing more than the discovery of a scientific principle (that oxygen below 2 pmm is what works in most such cases where we can’t have too much of oxygen as that would degrade the aqueous solution).
Tks—SB”
A patent is presumed to be valid unless held otherwise; Till that time-it is valid.
A fact that is being overlooked here is that the claimed “method” provides an advantage over existing methods that provide deoxy only to the extent of 2ppm max. The inventor is not claiming the principle-he is claiming a better way of performing the principle.
The spec provides: “However these methods have the disadvantage of allowing only a partial and insufficient elimination of the oxygen, or requiring a considerable amount of time.
The bubbling of nitrogen, the method most practised within the pharmaceuticals industry, only allows the oxygen content to be reduced to values of the order of 2 ppm maximum. b) neutralization of the oxygen dissolved in the aqueous solution, by the addition to the latter of an antioxidant such as a thiol or sulphur anhydride derivatives such as the sulphites, bisulphites or alkali metal metabisulphites. c) a combination of the elimination of oxygen and the addition of an antioxidant.
A method of this type has been described by the Applicants in the French patent 2.751.875.
As an FYI, this patent claims priority from a French application PCT/FR2001/001749 and also has a US equivalent # 6,992,218.
presumption of validity? in India?
you state:
” fact that is being overlooked here is that the claimed “method” provides an advantage over existing methods that provide deoxy only to the extent of 2ppm max. The inventor is not claiming the principle-he is claiming a better way of performing the principle.”
lets go by the claim first…we’ll resort to description etc to help interpret the claim. The claim reads as:
“A method for producing an aqueous solution of an active ingredient of phenolic nature which is paracetamol susceptible to oxidation, while preserving for an extended period characterized in that the solution is deoxygenated by bubbling with at least one inert gas and/or placing the solution under vacuum until the oxygen content is below 2 ppm, in that the afore-mentioned aqueous solution of an active ingredient, IS OPTIONALLY topped with an inert gas atmosphere and placed in a closed recipient in which the prevailing pressure is of 65, 000 Pa maximum, in that the oxygen content of the aqueous solution is below or equal to 2 ppm and in that the effect of deoxygenation of the solution is completed by addition of an antioxidant and a hydroxypolycarboxylic acid.”
The portion of the claim before “is optionally” stands on its own feet and is independent to that extent. And this part covers the entire gamut of all inventions that use inert gases to reduced oxygen levels in solutions below 2 ppm. Isn’t this obvious and/or overly broad?
It might be overly broad or even utterly obvious. But the point is the inventor has been granted a patent. Until a Court holds it to be invalid, the patent is valid.
The topping with inert gas is ‘optional.’ And not the part after that (Pressure, oxygen content, anti-ox and acid).
The optionally part in the claim can be read as being ignored from the claim (i.e. no need for topping with an inert gas atmosphere).
The essential elements of the claim are: oxygen content is <2ppm, 65K Pa and adding anti-ox+ acid.
@Neocog:
you’re simply begging the question. the issue here is whether or not this patnet is likely to survive a validity challenge. Besides, as you know, this is India….and not the US. we dont have a presumption operating in favour of the patentee. Secondly and more importantly, we have a post grant oppn mechanism…and one need not necessarily go to the court to knock down this patent..
Secondly, i’m not sure the claim has the term “optional” placed in the way you suggest. it reads:
“is optionally topped with an inert gas atmosphere and placed in a closed recipient in which the prevailing pressure is of 65, 000 Pa maximum…”
The most straightforward construction of this would mean that “optionally” qualifies all the features that follow in the claim….
By presumption of validity, I mean that a Controller or a Judge is the final authority on the claims.
I agree that the issue is whether or not this patent is likely to survive a validity challenge. But until the time it is revoked, it remains a patent.
As regards the construction of the term ‘optionally topped’, I am taking a broadest reasonable interpretation of the claim.
kindly see US PATENT 7,546,901, B1 – JUNE 16,2009 and US 6,274,185 B1 AUG 14, 2001
Its an anticipation
The patent stand revoked now ( Dec 2018) after the opposition was filed in 2011 prompted by an attempted drug patent linkage by the owner of the patent before the drug regulator during 2011.