True statement about phase 2 clinical trial is:

Phase II Clinical trial This is conducted by physicians who are trained as clinical investigators and involve 100-500 patients. The primary aim is the establishment of therapeutic efficacy, dose range in a controlled setting. Tolerability and pharmacokinetics are studied as an extension of phase I. they are single-blinded studies Ref; KD Tripathi pharmacology 7 th edition (page no; 80)