Introduction
What are dosage forms?
Dosage forms which is also called unit doses is the physical form of a dose of a substance used as a drug or medication intended for consumption or administration route of a patient diagnosis or treatment of disease. The drug molecules are delivered to sites of action within the body which in this case the bioavailability. Dosage forms are marketed for use and is a pharmaceutical drug product with a specific mixture of active pharmaceutical ingredients and inactive ingredients which is called excipients afterwards it is made into a particular configuration and distributed into a particular dose. Suitable dosage forms are needed for protection of the drug against destructive atmospheric oxygen or moisture, protection of drug from digestive juice on oral administration, to eliminate as much of the bitter taste and foul odour of the drug and provide extended drug action through administered release mechanism.
External administration dosage forms:
? Liniments= form of either fluid, semi-fluid or semi-solid preparations applied to the skin by rubbing. It is massaged into the skin to relieve pain and counter-irritant
? Lotions= it is fluid preparations applied to the skin without rubbing and covered with a waterproof sterile dressing to reduce evaporation
? Ointments= it is semi-solid greasy substance of water-in-oil (w/o) for application on the skin, rectum or mucous membranes. Composed of small droplets of oil dispersed in a continuous oily phase
? Paste= somewhat ointments like preparations which a high percentage of insoluble solid has been added. Afford greater protection and more absorptive action than ointments
? Creams= it is semi-solid emulsions that has mixtures of oil and water which meant oil-in-water (o/w). Composed of small droplets of oil dispersed in a continuous aqueous phase
Types of dosage forms and their Active Pharmaceutical Ingredients (APIs):
? Tablets/Capsules= pastes/powder and granules
? Soft gels/Oral liquids= oils, solutions, mixtures/powder and granules
? Ointment/Cream= powder and paste
? Inhaler= fine powder
? Suppository= powder and paste
Route of administration (ROA)
A route of administration is the way which a drug enters the human body system. Aside from taking a medication by mouth which is also called oral route, there is also injection into the muscle called intramuscular. Wearing a patch on the skin and inhaling the drug through the nose are two other common routes of administration as well. Applying patch on the skin is called either topical or transdermal and as for inhaling of drug through the nose is called inhalation. Topical effects the area where it is applied on the skin only but for transdermal once apply on the skin other parts of the body may be effected because it is being absorbed into the body to attain systemic distribution.
The choice of route various factors is on the physical properties which is solid, liquid and gas and chemical properties of the drug which is the solubility, stability, pH and irritancy. Site of desired action(bioavailability) which may be localised and direct or generalised and distributed. The rate of extent of absorption of the drug from different routes and the condition of the patient. Lastly the effect of digestive fluids and the first phase of metabolism.
Routes of administration:
? Oral
? Sublingual
? Topical/Transdermal
? Rectal
? Inhalation
? Parenteral= intravenous, intramuscular, subcutaneous
Oral administration
Oral route is generally the most common route, convenient and cost the least among other routes. Tablets and capsules have more higher drug stability and provide accurate dosage distributed in the body. But the downside of it is the unpredictability nature of the gastro-intestinal tract drug absorption. It may alter the gut pH, gastric motility and emptying time as well as the rate and extent of the drug absorption.
