Very simple, Search for the Pharmaceutical companey which manufactures the product containing that active ingredient and send them a request letter. I hope you will get the gift sample.
whoever entertains your request for gift sample letter will provide you with ....its really hard in India to carry on research work inspite of govt funding ...i saw in many other companies abroad have policies to support even the PG and PhD students for the gift samples...
You can send a request letter duly forwarded by your supervisor to the manufacturer of the product containing your active ingredient . Prefer to send it to the RnD unit of the manufacturing company. Another thing to do simultaneously is to get in touch with the RnD head or some authority which can respond to your mails and inform them about your need. I hope you will get it in some days. Try to ask for the sample from various manufacturing units selling the product in the market. This will increase your chances of getting a positive response in a good time.
Any progress? Just try a little bit hard and you will be succeeded. Just do as explained by Alok Nahata. He has described the proper way and channel for you. Regards