It's not clear what you want. Should you formulation be new and novel, you might be able to get a patent by disclosing the composition. If the formulation is already known and can be purchased elsewhere, then you cannot get a patent.

Most national patent offices have good websites that explain the patenting process. Have a look for example at the USPTO and the European Patent Office's website. 

If the formulation is novel, you should apply for patents right away and not wait

The health authorities are not going to be concerned about how many inventions or patents you have, so that's not a serious issue. 

A new formulation of a known drug is patentable in principle, but you have to have good arguments for why it's not obvious.  You need unexpected results, superior performance, or some novel (and useful) property, in order to get a patent.  And it has to be novel - not just over the products on the market, but over all known patents and publications.  You will need the advice of a patent professional, to evaluate your ideas and tell you if they're likely to be patentable.  

On the other hand, marketing approval is easiest to obtain when the new formulation is equivalent to the old one.  This is the opposite of what the patent office wants to see. So anything that's truly new and superior has a long and difficult path to market.  There's much less certainty, but potentially there are much greater rewards. 

Dear Dorna

In this knowledge based economy If you believe that the formulation is novel and not obvious to a person skilled in the art based on prior references either alone or in combination thereof please grab the priority by filing a provisional application. Then the patent office gives you one year time from the provisional filing date to work on your invention to its full swing for filing the complete application. Then it will gets published and thereafter examined. If the subject matter being claimed is proved to be novel and not obvious to a person skilled in the art then you get a patent on the same. Mind you the granted patent can further be subjected to opposition and / or revocation proceedings if the case has either been overlooked or misinterpreted by the patent office especially in terms of novelty or non-obviousness.

As James pointed out FDA or any health authorities would never bothered as to how many patents you own or being claimed as an inventor therein.

Hope this answer your question.

Best

Shaklain Khurshid

Indian Patent Agent (IN/PA/1987)

Manager- IPR (Biotechnology Division)

Biological E Limited

Hyderabad, India.

Dear @Dorna, obtaining patents is not cheap, and the task of managing a portfolio of them is serious work for a wide range of IP professionals. For many organizations, managing the IP portfolio may be one of the most critical business activities required to be successful.

Learn how to ensure that you have all of the tools and resources required to position your IP team for success....

Fine resource is attached.

http://stateofinnovation.thomsonreuters.com/ip-needs-assessment-are-your-business-requirements-being-met?utm_campaign=12707%20-%20Lead%20gen_Head%20of%20IP%20Admin_IPS_2016%20-%2031886&utm_medium=email&utm_source=Eloqua

What is needed is first to offer certified papers to patent status. Secondly, looking at the centers for the differences between the previous models similar to the model that you have to find or prove favorable your application for a patent. Positions are East Asia Center, the center of the European, American Center.

Dear Dorna,

here you can find two very good books/articles. I do hope they will help you.

Best regards,

Igor