ABSTRACT
This chapter outlines the basic principles of the manufacture of semi-solids and transdermal patches. The three principal attributes which can have a direct impact on the performance of all topical and transdermal products are the qualitative composition, the quantitative composition, and the physical microstructure. When developing a manufacturing process for topical or transdermal drug products, it is always important to consider the impact of an ultimate change in production scale as the programme progresses towards commercialisation. The processes considered during the process development phase should be as representative as possible of a potential commercial-scale manufacture and should be designed such that the resulting formulation meets the critical quality attributes defined and laid down in the Target Product Profile and release specifications. In the manufacture of topical semi-solids, fusion techniques are more widely used in industry compared to that of incorporation.
