Randomization will be done according to the blocks randomization method. Regarding to the sample size, 3 patients will be include in each block. According to 3 different doses of A-B-C, six different combinations of ABC, ACB, BAC, BCA, CAB, CBA exist. SAS procedure PROC PLAN will be applied to generate the random numbers. For numbers 0-1/6, 1/6-2/6, 2/6-3/6, 3/6-4/6, 4/6- 5/6 and 5/6-6/6 following combinations ABC, ACB, BAC, BCA, CAB, CBA will be assigned respectively.