You should adjust the condition of exp. inlet temperature, rate of flow and aspiration rate and you do your best to collect all particles outside the collector vessel. 

By adjusting the feed flow rate, with the inlet and outlet temperature (try to maintain the outlet temperature above 30 degrees celsius, if you have a feed flow of 11-30 ml/min)

I agree with Mohamed El-Badry and Florina Bunghez

Dear Divya,

Agree with the above answer. Adjusting the feed flow rate, inlet/outlet temperature and aspiration rate would help minimize the lost of spray-dried sample.

However, I would like to suggest that you use encapsulation agent or carrier agent such as maltodextrin, cylodextrin or gums to help you increase the yield of your spray drying sample.

Thanks.

You should optimize the parameters such as exp. inlet temperature, rate of flow and aspiration rate, encapsulation agent or carrier agent such as maltodextrin, cylodextrin or gums a with  highest collector vessel. after that used best combination for highest yield.

I agree with the answers, especially with Agarwal. I suggest to grasp the optimization issues with a fractional factorial design because there are many parameters (type of encapsulation, temperatures, flow rate etc). Later, you can refine it with a more precise factorial design.