# Setting limit on HPLC - Ovasis and other expert, pls comment

Hi

what we are following for the calculation for MACO and mg/swab of 10 X 10cm and derived the analytical limit in ppm is as given below.

is we following according to guideline, since the limit are always reaches below 10ppm (analytical limit).

MACO = TD x BS x SF / LDD
Where,
MACO: The maximum allowable carryover of product A into product B
TD: Single therapeutic dose of product A = 5 mg
BS: Batch size of product B (Minimum batch size in the Group, worst case) =5 lacs = 5,00,000 units
SF: Safety factor = 0.001
LDD: Largest daily dose of product B = 8 tablets

Calculation:

MACO = mg of active ingredient of product A permitted in Product B

= 5 x 500000 x 0.001 / 8 = 312.5

mg of permissible active per swab of 100 cm2 = MACO x Swab Area Equipment / contact surface area

= 312.5 x 100 / 59.6400 x 10000 = 0.052 mg / swab of 100 cm2

Setting analytical limt:
Now amount of solvent in ml is 20ml
So concentration in ppm is
= mg of permissible per swab of 100cm2 x 1000 / Amount of solvent in ml

= 0.052 x 1000 / 20
= 2.6 ppm