Application of QbD principles for the evaluation of empty hard capsules as an input parameter in formulation development and manufacturing

The empty hard capsules are supplied as an excipient that is filled by pharmaceutical manufacturers with a variety of different formulations and products. To understand the potential variations of the empty hard capsules as an input parameter and its potential impact on the finished product quality, a study was performed investigating the critical quality parameters within and in between different batches of empty hard gelatin capsules. Hard capsules can be considered as a suitable excipient for product development using QbD principles.