L3 Routes of drug administration L 4 Dosage forms of drugs Flashcards
Oral route
Dosage forms of drugs
- Liquid dosage forms
- Solid dosage forms:
(Absorption first requires:
dissolution of the tablet or capsule,
thus liberating the drug).
Routes of drug administration
ORAL
SUBLINGUAL
PARENTERAL
RECTAL
TOPICAL
INHALATIONAL
Preparations for oral administration are:
Solids
Tablets
Powder
Liquids
Capsules
Drug is protected from gastric acid, by a coat
Enteric-coated preparations
It dissolves only in the intestine and releases the drug in the alkaline media.
Enteric-coated preparations
Have special ingredients that control the drug release
Extended-release preparations
Allowing for slower absorption and a prolonged duration of action.
Extended-release preparations
Allowing for slower absorption and a prolonged duration of action.
Extended-release preparations
Advantages
1. Dosed less frequently
2. Improve patient compliance.
Extended-release preparations
Used for drugs that:
1. Acid unstable.
2. Irritating to the stomach
Enteric-coated preparations
what are the ADVANTAGES of Oral Route?
- Highly acceptable & easy to use.
- Cheap- Portable.
- Suitable for drugs given
for long-term. - Can prolong duration of
action by SR tablets.
what are the DISADVANTAGES of Oral Route?
- Unsuitable in emergency.
- Inactivation of some drugs
by gastric juice. (insulin) - Some drugs not absorbed
from GIT. - Some drugs are irritant .
- Food affect drug
absorption. (tea-iron) - Position of patient &
amount of water taken by patient.
Mucosal surface area of the small intestine is uniquely adapted for absorption,
Site of absorption of drugs after oral administration
Small intestine
(the bulk of drug absorption)
Acidic pH of the stomach favor the gastric absorption of acidic drugs (aspirin)
Site of absorption of drugs after oral administration
Stomach
what are the Absorption of different oral dosage forms ?
- Solutions, has relatively rapid absorption .
- Solid (capsules or tablets). must first disintegrate,
dissolve before absorption - Enteric-coated preparations released only in the intestine.
- Sustained-release preparations (release a steady amount of drug slowly and over long duration)
Drug inactivation before they reach systemic circulation, By:
- Gastric acid
- Digestive enzymes
- Enteric bacterial enzymes
- Intestinal contents.
- Liver
what is Sublingual Route?
• Placement under the tongue
• Allows a drug to diffuse into the capillary
network and enter the systemic circulation
directly.
what are the ADVANTAGES of Sublingual Route?
- Rapid effect with small doses.
- Nofirstpass metabolism in liver.
- Noinactivationin GIT.
- Canterminate effect by spitting out the tablet.
what are the DISADVANTAGES of Sublingual Route?
- Irritant to buccal mucosa.
- Suitableinsmall number of drugs.
what is Rectal Route?
Drugs may be given rectally for: 1. local effects (to treat proctitis)
2. or for systemic effect
what is the ADVANTAGES of Rectal Route?
- Avoid gastric acidity and digestive enzymes
- partly bypass The portal circulation
( no first pass metabolism) - For patients unable to swallow or who are vomiting.
what is the DISADVANTAGES of Rectal Route?
- Rectal absorption is often erratic and incomplete.
- Some drugs can be irritant to the rectal mucosa.
what is Inhalation Route ?
Provide rapid delivery of a drug across large surface area of the mucous membranes of respiratory tract and pulmonary epithelium.
A. Oral inhalation
B. Nasal inhalation
what is the ADVANTAGES of Inhalation Route ?
Rapid, convenient, Safe
Preparations For The Parenteral Route is:
Vial
ampoule
IV infusion
IV Cannula Size and color
Parenteral Route is:
I.V injection
I.M Injection
SC Injection
intradermal
Intra-articular
intrathecal
Intra- arterial
intracardiac
Characteretics of injectable solution:
Solution should be:
- Sterile (No mirco-organisms).
- Same PH and osmotic pressure as body fluids.
The parenteral route introduces drugs directly into the systemic circulation
Principles of drug administration
The three major parenteral routes
- intravascular (intravenous or intra-arterial)
- intramuscular,
- subcutaneous
• Uses of parenteral administration:
• used for drugs that are poorly absorbed from the GI tract (for example, heparin (SC))
• used for drugs that are unstable in the GI tract (for example, insulin(SC)).
• Used if a patient is unable to take oral medications
Suitable for agents that can be given in small volumes (≤2 mL) and are not locally damaging.
Subcutaneous route
warming the tissue, Massage of the injection site, promotes drug uptake by improving local circulation
Subcutaneous route
for drugs that cannot be given orally (slow absorption, drug inactivation,)
Intramuscular route
types of Intramuscular route:
- Aqueous solutions, (absorbed rapidly)
- Depot preparations, (absorbed slowly).
Disadvantages of IM ROUTE:
- Pain, Sterile abscesses, Haematoma
- Sciatic nerve palsy
- No way of stopping absorption
Intravenous route ADVANTAGES OF IV Route:
- For drugs not absorbed orally
- Rapid effect
- Control the amount of drug delivered.
- For solutions too irritating for other routes
DISADVANTAGES of IV Route:
- Toxic reactions can be immediate, severe.
- Given drug cannot be recalled (by activated charcoal)
- Vasculitis, hematoma , hemolysis, Infection, embolism formation
- Accidental intra-arterial injection may led to arterio-spasm, gangrene, and loss of limbs.
If administered to quickly Nonspecific but potentially disastrous ……………. ………………. ………….. may result, even from the rapid injection of simple salt solutions.
cardiopulmonary side effects
Slow absorption can be achieved by the use of depot forms as for …………………….. …………………….. ………………………
intramuscular injections and subcutaneous injections.
• But IV injection …….. ………….. effects
rapid immediate
Drugs applied to skin or mucous membrane for local effects
Topical Application
Topical drugs through
EYE, EAR, NOSE & VAGINA
• Dosage forms of oral preparations
- Liquid dosage forms: syrup – suspension-emulsion
- Solid dosage forms: Powder- Capsules- tablets –Sustained release tablets/capsules –Enteric coated tablets/capsules
Dosage forms of parenteral preparations
Vials- ampules
• Dosage forms of topical preparations
Ointment – creams- gel- transdermal patch- eye drops – ear drops- nasal drops
Ointment – creams- gel- transdermal patch- eye drops – ear drops- nasal drops
Enemas – suppositories –cream
