Routes of Drug Administration Tissue Engineering & Drug Delivery BBI 4203 LECTURE #11

Classifications for route of administration Path by which a drug, fluid, poison, or other substance is taken into the body. Generally classified by the location at which the substance is applied. Common examples include oral and intravenous administration. Also can be classified based on where the target of action is. topical (local) enteral (system-wide effect, but delivered through the gastrointestinal tract) parenteral (systemic action, but delivered by routes other than the GI tract)

Gastrointestinal/enteral Administration through the gastrointestinal tract Enteral -- literally meaning 'through the intestines’ Includes oral and rectal administration Pills Suppositories

Epicutaneous or topical Application of creams or salves onto the skin Drug diffuses through skin in a transdermal route

Intravenous administration Administration into a vein Most common drug, fluids and nutrition infusion route

Central nervous system Epidural: injection or infusion into the epidural space. relieve pain during child birth Intracerebral: direct injection into the brain. can also interrupt the blood brain barrier from holding up against subsequent routes Intracerebroventricular: injection or infusion the ventricular system of the brain. pain meds for terminal cancer patients with intractable pain

Nasal administration Can act topically through the nasal epithelium Or taken up through the respiratory tract as an inhalant

Intra-arterial administration Administration into an artery vasodilator drugs in the treatment of vasospasm thrombolytic drugs for treatment of embolism

Intra-articular administration Administration into a joint space. Used in treating osteoarthritis Corticosteroids or hylauronic acid

Intracardiac administration Administration into the heart (emergencies) Injection of adrenaline during cardiopulmonary resuscitation Direct injection

Adrenalin injection scene from the movie Pulp Fiction John Travolta, Samuel L. Jackson, Uma Thurman https://www.youtube.com/watch?v=jpMxpzfSRUA

Intramuscular administration Administration into a muscle Many vaccines, antibiotics, and long-term psychoactive agents.

Intraocular administration Medications for glaucoma or eye neoplasms

Intraosseous infusion Administration into the bone marrow that drains directly into the venous system. Occasionally used in emergency medicine and pediatrics when intravenous access is difficult.

Intraperitoneal administration Infusion or injection into the peritoneum Peritoneal dialysis

Intrathecal administration Administration directly into the spinal cord Most commonly used for spinal anesthesia, pain relief, and chemotherapy Epidural Intrathecal

Subcutaneous administration Administration under the skin Vaccines, insulin, morphine, injection Commonly used in with recreational drugs

Transdermal administration Diffusion of drug through the intact skin Transdermal patches such as fentanyl in pain therapy, nicotine patches for treatment of addiction and nitroglycerine for treatment of angina pectoris, hormone therapy.

Transmucosal administration Drug diffusion through a mucous membrane Insufflation (through nasal membranes), sublingual (under the tongue), sublabial (between the lips) and gingiva (between cheek and gum), nitroglycerine, vaginal suppositories Nitroglycerin pill for relief of angina Snorting drugs

Controlled release Most commonly it refers to time dependent release in oral dose formulations such as prolonged release, pulse release, delayed release. Attempts to maintain drug levels within the therapeutic window to avoid potentially hazardous peaks in drug concentration following ingestion or injection.

Targeted drug delivery Delivering medication in a manner that prolongs the concentration drug in diseased tissues and minimizes concentration in non-diseased tissues. Reduces total drug dose and frequency of administration. 3 main mechanisms physically locate the drug depot at the diseased site use molecular recognition to bind circulating drug to diseased tissue mechanism that bursts open circulating drug carriers at site of diseased tissue

“Homing” liposomes and drug eluting stents

Infusion pumps Pump-controlled infusion of drug Large volume pumps can pump nutrient solutions large enough to feed a patient. Small-volume pumps infuse hormones, such as insulin, or other medicines, such as opiates.

All drugs move through three tissue compartments Cells Blood and lymph vessels (1 - 10%) Interstitial space

Different fractions, types and orientation of cells, ECM, interstitial space, vasculature in different tissues