Discussion on sampling method of 1 m3 for grade A area by Good manufacturing practice for medicinal products

The requirement, the total sample volume should not be less than 1 m3 for grade A area which is described in Good manufacturing practices for medicinal products, derives from the minimum sampling volume demand of twenty particulates required by ISO standard（the former edition is 209C）. According to the requirement, the corresponding sampling time is too long. On the basis of the explanation of GMP, which recommends the sampling method referring to ISO 14644-1, considers that a discrete airborne particle counter with 28.3 L/min sampling flow rate could be used for monitoring the concentration of particles only once at one sampling point in the grade A area, or using the sequential sampling procedure. Based on the sequential sampling method, the sampling time may be shortened to at least eight minutes for each sampling point.