Novel Drug Delivery Systems (NDDS)

Introduction & rationale

• Definition — a drug delivery system (DDS) is the formulation/technology that governs where, when and how fast a drug reaches its site of action; a novel (NDDS) system deliberately goes beyond the conventional pill/injection to control release rate and/or localisation.
• Why NDDS exist — conventional administration (pill or injection) offers limited control over release rate and over localisation — NDDS overcome these two limitations by altering one or more of the four PK processes (absorption time-course, distribution/targeting, metabolism avoidance or prodrug exploitation, elimination).
• Therapeutic advantages — maintain levels continuously within the therapeutic window (no peak–trough swing); reduce adverse effects by abolishing transient peaks; reduce total dose and dosing frequency → adherence; deliver short-half-life peptides/proteins via controlled-release polymers.
• Modified-release definition — a modified-release (MR) dosage form deliberately chooses the time-course and/or location of release to achieve objectives not offered by conventional immediate-release (IR) forms.
• New design concerns — each material and its degradation products need toxicity evaluation; risk of dose dumping (unwanted rapid release); device discomfort; and increased cost.