Drug Delivery Flashcards
Common routes of drug administration
Oral, intravenous injection/infusion, intramuscular injection, subcutaneous injection, transdermal, ophthalmic, buccal, vaginal, controlled release implants
Define controlled drug delivery
Engineering of physical, chemical, and biological components into a system for delivering controlled amounts of drug to target location for prolonged period
Sustained release
Decreasing concentration over time
Bolus dose
Repeated administration
Zero order released
Constant concentration over time
Therapeutic range
When the drug concentration is between the minimum effective concentration and the toxic level
Temporal delivery
Control over the rate of drug release. Generally release is over a long period (day to weeks or even months)
Spatial delivery
Control over location of drug release. Targeted release or local delivery
Mechanical pumps
Miniature infusion system; implantable or via catheters; used to deliver insulin, anticoagulants, analgesics, cancer chemotherapy
Advantages: precise control over delivery, can be coupled with biosensors for feedback control
Disadvantages: agents need to be stable in solution at body temperature, bulky, and expensive
Polymer controlled drug
Diffusion-controlled systems: reservoir devices, monolithic (matrix) devices (nonerodible)
Solvent-controlled systems: osmotically controlled devices, swelling controlled devices
Chemically-controlled systems: drug covalently attached to the polymer backbone, drug in a core surrounded by a bio-erodible rate-controlling membrane, drug homogeneously disbursed and in a bio-erodible polymer
Diffusion-controlled systems
Drug release controlled by drug diffusion through polymer
Solvent controlled systems
Drug release activated by swelling action of water
Chemically-controlled systems
Rate of release determined by rate polymer erosion or kinetics of bond degradation
Important considerations of drug transport
Diffusion of molecules across porous membranes, uptake and transport into cells, diffusion in polymer solutions and Jills, diffusion through porous matrix, pharmacokinetics
