Routes of Drug

Administration

UG08-20-12-066MD.JAKIUL ISLAMDEPARTMENT OF PHARMACY

Definition:A route of administration is the path by

which a drug, fluid, poison or other substance is brought into contact with the body.

Physical chemical properties of the drug Site of desired action Route and extend of absorption of drug different routes Effect of digestive juice and first pass metabolism Rapidity of desired response-emergency Condition of patient

CHOICE OF ROUTES:

First pass effect

First pass effect:

1) Local -topical -deeper tissues -arterial

2) Systemic -oral -sublingual -rectal -nasal -inhalation -parenteral

CLASSIFICATION

External application to the surface

Application on/to skin,eye,ear canal.vigina etc

Dosages forms- lotion, ointment, cream, paint, drops spray

Topical

Intra-articular injection Intrathecal Retrobulbar injection

Arterial Contrast media in angiography

Anticancer drug for limb malignances

Deeper tissues

Drug is absorbed into blood stream to reach the site of action

Oral- Advantages – safe and convenient painless and comfortable Sterilization not required so cheaperDosages forms: solid- tablet, capsules Liquids- syrup, emulsion Disadvantage: First-pass effect - drugs absorbed orally are initially

transported to the liver via the portal vein irritation to gastric mucosa - nausea and vomiting

Systemic routes

Advantages: rapid absorption Avoid fast pass effect Drug stability is better

Disadvantage- only lipid soluble and nonirritating drug can be given.

Example- Nitroglycerine

SUBLINGUAL ROUTE

Example: suppositories, retention enema

Advantages- in vomiting or unconscious patients

Disadvantages: absorbtion- irregular, slow -rectal inflammation

-50% drug bypass liver

Rectal route

◦Intravascular (IV, IA)- placing a drug directly into the blood stream

◦Intramuscular (IM) - drug injected into skeletal muscle

◦Subcutaneous - Absorption of drugs from the subcutaneous tissues

◦Intradermal

Parenteral Routes

slow and constant absorption

absorption is limited by blood flow, affected if circulatory problems exist

concurrent administration of vasoconstrictor will slow absorption.

SUBCUTANEOUS ROUTE

Site- deltoid, vastus lateralis, rectus femories

self injection is not possible

depot preparation can be used

more vascular and less nerves

INTRAMUSCULAR ROUTE

Advantages: -immediate effects, useful in emergencies -irritant drug can also be injected -100% bioavailability -large volume can infusedDisadvantages: - no depot preparation -risky

INTRAVENOUS ROUTE

Injected in the skin by raising multiple scarring

Example: skin testing BCG vaccine

INTRADERMAL

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