The concept of gaamitva is very important with respect to kalp. The action of any kalp is depending on various factors. Gaamitva is one of the factors. When a particular kalp is said to act on particular vyaadhi it has to work on particular srotas, particular dosh-dushya samurchana.
Take an example of letter. To reach at particular place the address is very important. You can’t post a letter without writing address on it. Same is about the kalp. As the address written on a letter delivers the letter at correct place, the gaamitva of drug decides where to go in our body and act.
Our body has a definite structure so does the dravya. Hence a particular part of dravya has action on particular body. Most of seeds are vrushya i.e. they reach up to the level of gametes in our body.
Shalmali kantak is used for local application in mukhdushika / pimples (acne). On external appearance Shalmali kantak itself looks like pimples hence it has capacity to work on pimples. This is gaamitva.
According to ayurveda Lungs are made up of Rakta Phen. Rakta dhatu gives origin to Phuphus/Lungs. Phen means bubble like appearance or foam. So any drug having appearance like Rakta Phen will have capacity to reach Lungs. Praval or coral is such drug. It is reddish in color, porous structure and appearance like bronchial tree. So Praval works on Lungs.
The role of bhavana dravya is very important in this case. Most of the bhavana dravya provide the drug delivery system. In case
of Tribhuvan Kirti rasa, Aadarak swaras provides medium to reach Rasavah Srotas. All contents are delivered to Rasavah Srotas where they act and Jwaraghna action is seen.
We give krumighna medicine with anupan of gud, in which gud reaches to site of krumi and the krumighna property is seen. Til is Kushthakar i.e. it gives rise to Kushtha but Til given with Bhallatak reduces s Kushtha.
Gaamitva for particular part in our body for a drug can be achieved by Samskar, Bhavana or Anupan. Triphala is given with Sita (Sugar) in Prameha. Sugar delivers Triphala to Rasa, Meda, and Maans etc so Prameha is cured.
So if We can understand this concept of Gaamitva, We can achieve exact drug delivery system in our body.