Computation of in-house quality control limits for pharmaceutical dosage forms based on product variability

A method for establishing sampling plans for in-house limits that fix both the producer's and consumer's risks is presented for pharmaceutical systems in which both between-batch and within-batch variations are present. Such plans can always be constructed and require more or less sample assays depending on the variability of the process. The computations involve a numerical approximation to the bivariate normal distribution.