Final answer:
Excipients are non-medicinal substances added to drugs to facilitate drug formulation and delivery by providing necessary weight and volume, and include common agents like lactose or cellulose.
Step-by-step explanation:
In the context of pharmaceutical sciences, excipients refer to substances formulated alongside the active ingredient of a drug. Their primary purpose is to bulk up the product, facilitating drug delivery by aiding in weight, volume, and consistency.
Excipients play no medicinal role but are crucial for product stability, efficacy, and patient acceptability. Common examples include lactose or microcrystalline cellulose used as fillers in tablets or capsules.