Introduction to Drug Delivery Flashcards
What is drug delivery?
- It refers to a dosage form that deliver the active pharmaceutical ingredients to the site of action
- Provide a reliable delivery of drug at therapeutic concentration to biological target (Organs, tissues, cells)
- Minimise the exposure of the drug to other non-biological target to avoid adverse effect
What is a dosage form?
Is a final formulation contain APIs and excipients produced by one or more pharmaceutical manufacturing process. E.g. tablet, capsule, syrup…etc.
what is a API?
Are pharmacologically active chemical compounds, used for prevention, diagnosis or treatment of various diseases.
Can we administer API directly?
- API handling can be difficult, in particular for potent drugs (e.g., low mg and g doses)
- Some API can be sensitive to moisture and light. Their chemical stability may compromise.
- API can have unpleasant taste or smell – need to consider patient compliance.
- Some API are poorly water soluble and cannot be readily administered.
What are excipients?
Excipients are inactive pharmaceutical ingredients
- Lubricant
- `Binder
- Diluent
What are the main types of dosage forms?
Solid
o Powder: used in solution, suspension or topical
o Granule: used in solution, modified release
o Tablet: chewable, effervescent , modified release
o Capsule: powder filled, liquid filled, contain modified release
Liquid
o Solution: API dissolved
o Suspension: Solid API suspended
o Emulsion: Oil in water and water in oil
Semisolid:
o Ointment: API dissolved or suspended
o Cream: oil in water and water in oil
o Gel: API dissolved or suspended
Gaseous:
o Aerosols: API solution droplets suspended
o Medical gases
Factors that determine the choice of route of administration include:
- Patient compliance (easy of administration)
• some patients are unable to swallow
• Patient experiencing nausea and vomiting - Site of action
• local administration: when the biological target is external or easily accessible e.g. Topical drugs, GIT (antacid), eye (conjunctivitis), bronchodilator (asthma)
• Systemic administration: when the biological target is internal and not easily accessible.
• The blood within the circulation system carries the drug throughout the body
• Reaching the drug to blood circulation can be :
• Direct – intravenous injection
• Indirect – oral, pulmonary or transdermal (the drug must release first) - Onset of action
Onset and rate of action varies depends on how quick the drug reach the biological target.
Solid and semi-solid preparation: the drug is formulated into the dosage form such as tablet or capsule, cream or ointment. The drug must first release from the formulation, absorbed and then reach the site of action. Therefore there is a delayed onset of action.
• Liquid solutions or suspensions work faster than oral tablets or capsules • medication is more readily available for absorption - Duration of action
• Controlled- /extended-release tablet may last for 12 to 24 hours compared with 4 to 6 hours for
same drug in immediate-release formulation
• Transdermal patches deliver small amounts of a drug steadily over many hours or even days
• Sustained-duration effect can be achieved by means of intravenous (IV) infusion
• Injections into the muscle and skin last longer than injections directly into the bloodstream - Quantity of the drug
• The amount of the drug to be administered will influence the choice of route of administration
• Low quantity of potent drugs is easier formulated into tablet dosage form, and the control of the
dose is much easier
• Intravenous injection is often easier for a large quantity of drug as it quickly dilute in the blood circulation - Liver metabolism of drug
• First-pass effect: refers hepatic metabolism of drugs when absorbed from GIT through hepatic portal veins. The metabolite is inactive form with no pharmacological effect.
• The higher hepatic metabolism the less amount of drug reach the biological target in active form. • The drugs therefore are given either in larger does or through a different routes of administration.
what does parenteral mean?
injection
what is Sublingual administration?
under tongue, avoids first pass effect
what is buccal administration?
between check and gum, avoids first pass effect
Advantages of oral dosage form
Commonly:
• Easy and safe administration • Non-invasive
• Pain-free
• Economical
• Large surface area for absorption through GIT
• Can be used to avoid first –pass (sublingual and Buccal)
• Drug absorption is quick and can be easily terminated upon adverse effect (sublingual and Buccal)
Disadvantages of oral dosage form
- Oral route has a delayed onset of action
- In case of tablet, the tablet must disintegrate and release the drug before absorption • Food or GIT fluid may interfere with drug absorption
- Can not be recommended for patients with nausea or vomiting or when unconscious • Some API has a bitter taste - patient compliance
In case of Sublingual and Buccal administration
o Short duration of action – not appropriate for routine administration o Possible irrigation or unpleasant taste or mouth feeling
Parenteral routes of administration must be ? conditions
Theymustbe: I.V o STERILE – free of microorganisms (microbiological tests)
o PYROGEN-FREE (test for pyrogen)
o ISOTONIC (sodium chloride is added)
Advantages of Parenteral route
- Is a fast method of delivery of drugs into blood circulation
- Critical in case of emergency conditions
- Vital to administer fluids, electrolytes and nutrition
- Allows for bolus administration of drugs such as antibiotic in serious bacterial infection
- Avoid first pass metabolism by the liver
Disadvantages of parenteral route
- Patient compliance
- Pain at the site of injection
- Potential for infection
- Difficult to stop or reverse if adverse effect occurs
- Require trained person to administer
