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 nature of illness 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 specific configuration and distributed into a specific dose. Suitable dosage forms are needed for protection of the drug against harmful exposure of sunlight (UV rays) or moisture and another protection would be against digestive juice on oral administration. Also to mask off the bitter taste and foul odour of the drug and provide extended drug action through administered release mechanism.
Types of dosage forms and their Active Pharmaceutical Ingredients (APIs)
Tablets consist of pastes and Capsules consist of powder and granules. Soft gels consist of oils, solutions, mixtures and Oral liquids consist of powder and granules. Ointment, Cream and Suppository consist of powder and paste. Lastly Inhaler consist of fine powder.
External administration dosage forms
Liniments is a 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 is a fluid preparation applied to the skin without rubbing and covered with a waterproof sterile dressing to reduce evaporation. Ointments is a 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 is somewhat ointments like preparations which a high percentage of insoluble solid has been added. Afford greater protection and more absorptive action than ointments. Creams is a semi-solid emulsion 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.
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. 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. There are 6 routes of administration and that is by Oral, Sublingual, Topical/Transdermal, Rectal, Inhalation and Parental via intravenous, intramuscular or 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.
Sublingual administration
Sublingual is design as such where the tablet is place under the tongue. It offers a very fast drug release and a rich supply of blood vessels absorption under the tongue. Common example would be nitro-glycerine tablets for treatment of acute relief angina. Another method would be buccal placing the tablet between the gum and the cheek.
Topical/Transdermal administration
Topical can be define as application to a localized area of the body and also includes transdermal application. 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 affected because it is being absorbed into the body to attain systemic distribution. Patches may irritate the skin of the person applying it and once apply the therapeutic effect of the drug penetrates through the skin, but it is limited. That is why eventually the therapeutic effect wears off over time.
Rectal administration
It is like a form of soft gels like capsule usually cone shaped where the drug is mixed with a waxy substance that solubilize after it is inserted into the rectum and the drug is readily absorbed once inserted where it melts at body temperature. Patients before and after surgical operations are prescribe by the doctor by this administration which are called suppository. The reason they are prescribed with this form of method is because the patient cannot take drug orally because if they take orally it will cause them nausea.
Parental administration
Parental means is a non-oral way of administration by sterile injection and there are 3 ways of doing so. Intravenous, intramuscular and subcutaneous. Intravenous inserts the needle into the vein and the solution of drug may be given by single dose or continuous infusion. It gives precise dose quickly and distribute throughout the body in a well-controlled manner. Intramuscular inserts the needle into the muscle of the upper arm, thighs or buttock. How fast the drug absorbs depends on the blood supply to the muscle which means if the blood supply scatters, it will take longer for the drug to be absorbed. Subcutaneous inserts the needle into fatty tissue just beneath the skin directly below the dermis. Once injected the drug moves into the capillaries where it is carried away by the bloodstream.
Inhaled dosage forms
Generally, nebulizer mask is one of the inhalation route use for patients. It is a device use to administer medication to patients in a form of liquid mist to the respiratory system. There are also inhalers commonly used to treat asthma which the patient inhales the released of drug through a mouthpiece. Nebulizer is classified as sprays and as for inhaler it is classified as inhalant and both are considered as an external administration. There is also nasal inhaler which is decongestant drug and its intended purpose is to relieve nasal congestion or blockage of the nose. They are sold over the counter without any prescription. As for inhaler and nebulizer it must have prescription with a doctor. Inhaled medication absorption rate is very rapid and quick which can act both locally and systemically.
Inhaler
Inhaler which is also called puffer or pump is a little device which deliver medication into the body and straight to the lungs. Inhalers are use to treat the condition of affected lungs which is asthma and chronic obstructive pulmonary disease in short term COPD. The medication is in a canister consist of either solutions, suspensions or emulsion. It has an inert propellent held under pressure. Mechanism of the inhaler is through a spring-loaded valve actuated by finger pressure
There are two types of inhalers and that is metered dose inhalers (MDI) and dry powder inhalers (DPI). MDI uses aerosolized medicine which is stored in little aerosol cans and it works by propellant which is suspension of fine powder by spraying out. DPI uses powdered medicine which relies on force of the person using it and that is by force inhalation of the carrier powder lactose. It is two different form of medicine that is use but the active pharmaceutical ingredient is the same that is fine powder.
Nebulizers or also can be called atomizer commonly used to treat asthma, COPD, cystic fibrosis and other respiratory diseases. It pumps in oxygen through a liquid medicine and change into vapor which is then inhaled by the patient. That liquid medicine is a solution and suspension which break up into small aerosol droplets. Normally it is use in hospitals because it can be quite noisy and hard to bring it around. Commonly use in hospital because it can store large amount of high dose inhaled medicine and to treat patients with serious case of severe asthma attack or respiratory disease. There are different type of nebulizers electric and mechanical. Under mechanical there is soft mist inhaler and electric would be jet nebulizer, ultrasonic wave nebulizer and VMT (vibrating mesh technology) nebulizer.
Asthma is a long-term inflammatory disease of the airways in the lungs and how asthma came about is by genetic and environmental factors. Environmental factors would be air pollution and allergens. Symptoms of having an asthma would be wheezing, coughing, chest tightness and shortness of breath. Most likely before the age of 12 years old it is considered genetic factors and is called childhood asthma and if it is after 12 years old of age it will be more likely be due to environmental factors. There is no absolute cure for asthma, but symptoms can be prevented by avoiding triggers such as asthma attack. Asthma attack are triggered by allergies such as food/ food additives, fragrances, smoke or chemical fumes, airborne particles like dust mites, pollen and mold spores. Even physical exercise and bad weather may trigger asthma attack.
COPD is a chronic inflammatory lung disease that blocks airflow from the lungs, the main symptoms is chronic cough, difficulty breathing, excess mucus in the lungs and wheezing. The main cause of this disease is smoking and other irritants would be second-hand smoking, air pollution, exposure to dust, smoke and fumes.
