Routes of administration Flashcards
Form of the drug will influence the route of administration / formulation choice. TRUE OR FALSE?
TRUE
Solubility determines injection volumes; greater solubility means a drug can be injected in smaller volumes. TRUE OR FALSE?
TRUE
Cachectic patients (i.e
muscle wastage) and for
subcutaneous use
lipid solubility is important for partitioning in biological systems, such as blood-brain barrier partitioning. TRUE OR FALSE?
TRUE
What is biovailability?
The fraction/ concentration of the drug that reaches systemic circulation and to its targeted effect
Give an example of a drug that has similar biovailability to that of IV?
antibiotic ciprofloxacin - it is well absorbed by the gastrointestinal mucosa
Give an example of a drug that has low bioavilability?
beta-blocker propranolol when given orally is administered in doses of 40mg and above. The equivalent IV dose is 1mg
The route of administration and its formulation (tablet, capsule, liquid) can
clearly influence the bioavailability of a drug. TRUE OR FALSE?
TRUE
What is a dosage form?
It describes the physical form in which the drug is delivered to the body
what is an Excipients?
Allows for effective administration and delivery of a drug e.g injections (isotonic solutions) and tablets (disintergrates)
What is the role of Excipients in drug formulation and delivery?
- Diluents
- Surfactants - emusifying, suspensions can change drug bioavailability
- Lubricants - can help distintegrants tablets and capsules/ reduces friction during manufacture e.g manufacturing of diprivan used in rubber bug
- Changes viscosity
- Flavouring and colour
What are the main considerations for effective administration of drug?
- The physicochemical properties of the drug
- Biopharmaceutical considerations, for example, how the route of administration of a dosage form affects the rate and extent of drug absorption in the body
- Therapeutic considerations of the disease state to be treated, which in turn decide the most suitable type of dosage form, possible routes of administration
- Clinical compliance
- Product safety
- Regulatory issues
Give examples of different types of routes of administrations?
Oral, rectal, vaginal, buccal, pulmonary respiration, parenteral, nasal, eye
What is Systemic or local delivery?
Systemic – Delivery of the drug to a site other than that to which it is applied, i.e. a transdermal patch delivers, a hormone across the skin
Local – Delivery of the drug directly to the intended site
of action, i.e. eye drops, creams, etc.
What is the onset time of a drug?
The speed at which the drug action commences will vary according to the route of administration.
Give an example of a drug that has different types of administration routes?
Glyceryl trinitrate: – Prophylaxis and treatment of angina; left ventricular
failure – Several different routes of administration
• i.e. sublingual sprays and tablets, buccal tablets, tablets, various
transdermals, etc. (cf. BNF)
What are Topical and transdermal?
Topical:
– Delivery to the skin
– Examples: treatments for eczema or psoriasis
Transdermal (percutaneous)
– System delivery using the skin as a rate-limiting mechanism
– Example: HRT or fentanyl patches
What are the advantages and disadvantages of Topical and transdermal?
Advantages: – Bypass the hepatic metabolism – Sustained or controlled release possible – Patient-controlled Disadvantages: – Very few drugs go through the skin – Local irritation at site of application – Expensive
What are the methods for increasing transdermal delivery?
Increase the skin hydration Increase the skin temperature Adjust pH so that the drug is unionised Increase the drug concentration Control the molecular size of the drug (100 – 500 ideally, possibly 100 – 800)
What are the Factors affecting systemic GI delivery (for oral delivery)?
– Gastric emptying
– Motility - how the drug is able to move around
– Volume of contents
– Eating
- Clinical convenience; i.e. patients who cannot or
will not (children) take tablets or capsules
What are the Common routes of parenteral administration?
intramuscular (IM), subcutaneous and IV, implants and irrigation
What is parenteral route of administration?
Delivery through directly through non oral means
What are the advantages and disadvantages of parenteral administration?
Advantages of parenteral administration:
– Drugs that are poorly absorbed, inactive or ineffective if given orally
can be given by this route
– The intravenous route provides immediate onset of action
– The intramuscular and subcutaneous routes can be used to achieve
slow or delayed onset of action
– Patient compliance problems are largely avoided .
Disadvantages of parenteral administration:
– Requires trained staff to administer
– Can be costly
– Can be painful
– Aseptic technique is required
– May require supporting equipment for example, programmable infusion devices
How are Pulmonary Drug Delivered and provide examples?
Aerosols: colloidal systems of very finely subdivided
liquid or solid particles dispersed in and surrounded
by a gas
e.g space sprays, surface coating and aerated sprays
What are the advantages of Pulmonary Drug Delivery system?
Advantages:
– Quick action
– Smaller dose required than is needed for oral or
intravenous delivery
– Therefore, there is potential to reduce the systemic side effects
What are the different types of rectal preparations?
Enemas - Arachis oil
Rectal solutions - diazepam (to treat seizures) drug
Suppositoires - paracetamol
The lower (inferior) and middle hemorrhoidal veins
bypass the liver-and do not undergo first pass
metabolism.
This means that drugs could go directly to the
organs of your body without being filtered through
the liver first. True or false?
TRUE
What are the disadvantages of using rectal route of ADMIN?
1.Patient compliance
2.Absorption can be variable
– pH - no buffer capacity
– Motility
3.Colonic contents
– constipation
– diarrhoea
– Obstructions
4. Tumours
5. faeces
6. Haemorrhoidal veins
