Methods of Drug Delivery

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Chapter 3

• Methods of Drug Delivery

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Delivery of Drugs

• Enteral digestive tract
• Parenteral major route Given into the
  cardiovascular circulation
• Topical by application onto the skin or
  associated membranes

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Process of Drug Delivery

• Drug Administration Phase depends on form of
  med, speed medication action is needed, desired
  location
• Enteral
• Parenteral
• Topical

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Process of Drug Delivery

• Pharmacokinetic Phase movement of drugs
  throughout the body to various targets
• Absorption
• Distribution
• Metabolism
• Excretion

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Process of Drug Delivery

• Pharmacodynamic Phase drugs produce a change or
  an effect at a specific target (receptor)
• Efficacy
• Potency

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Physical Properties

• Influence how medications enter and move
  throughout the body

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Physical Properties

• Solids most effective via a body opening, need
  to dissolve first to become active, which slows
  the process

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Physical Properties

• Liquids- move quicker through the body but need
  to penetrate the cellular membrane, viscosity can
  make it more difficult if it is higher,
  solubility the ability to dissolve will affect
  how easily it passes across the membrane

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Physical Properties

• Hydrophobic- dissolve in lipids, work better
  penetrating body membranes

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Physical Properties

• Hydrophilic dissolve in water, work better in
  the bloodstream

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Physical Properties

• Gas
• Fast absorption, moves quicker to target area
  and action is in seconds

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Oral Route

• By mouth
• Can be chewed, swallowed, or dissolved in the
  mouth
• Tablets, capsules, powders, solutions,
  suspensions
• Dissolution delays the onset of action, water is
  needed or may be taken with food

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Sublingual

• Absorbed quickly into the bloodstream
• Avoid the first- pass effect intestinal
  absorption into the portal circulation to the
  liver to be metabolized by the liver

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Rectal

• Use with unconscious patients, patients with N/V,
  infants not able to swallow pills
• Rapid onset of action due to blood supply

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Injection Into the Blood Vessels

• IV
• Bolus
• Infusion
• Bypasses destructive enzymes of GI tract and the
  liver
• Fluid overload, infection

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Injections

• Intradermal dermis
• easily
  absorbed
• Subcutaneous hypodermis
• Intramuscular muscles
• faster onset of
  action

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Injections

• Advantage IM and subcutaneous
• Concentration of drug is predictable
• Confined to a precise location
• May be given to unconscious patients and children
• Disadvantage IM and subcutaneous
• Pain, swelling, tissue damage, infection

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Injections

• Intrathecal directly in spinal subarachnoid
  space(dorsal spine spinal cavity beneath a sheath
  surrounding the spinal cord called the anrachnoid
  mater) spinal anesthetics or medications that
  might enter the cerebral spinal fluid

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Injections

• Epidural directly into a space overlying the dura
  mater (most superficial layer of that protects
  the CNS)

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Injections

• Intraperitoneal directly into the abdominal cavity

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Injections

• Into the joint spaces (analgesics and anti-
  inflammatory drugs)

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Topical

• Skin
• Eyes
• Ears
• Nasal membranes
• Reproductive openings
• Effect is systemic or local

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Transmucosal Drugs

• Cross membrane lining
• Respiratory
• Reproductive tracts
• Effect systemic or local
• Forms suppositories, sprays, mists, foams,
  aerosols, volatile agents
• Examples asthma, vaginal infections

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Ears and Eyes

• Eyes
• Effect to lubricate, prevent inflammation or
  treat infections of the cornea
• Forms ointments, salves, or drops
• Ears
• Effect to treat infections, cerumen buildup
• Forms drops ( need to penetrate the ear canal
  and middle ear to be effective)

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Client Teaching

• Oral take with water or food to reduce nausea
• Establish a routine
• Follow dosing times, do not play catch up
• Store medication in a dry safe place
• Discard outdated medications
• Take medications with calibrated insert provided

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End