Dosage form is a mixture of active drug component and nondrug component. Depending on the type of admistration it is of several types. They are liquid dosage form, solid dosage form and semisolid dosage forms.
Oral Dosage Forms
A) Tablets
Tablets are a solid dosage form which varies in size, weight, shape, and other ways. There are a couple different tablet types.
Enteric-Coated tablets have a coating on them which causes them to be dissolved in the intestinal tract instead of in the stomach. An example is Enteric-Coated Aspirin.
Buccal tablets are intended to be placed in the buccal pouch (between the gums and the cheek) and slowly dissolved. This dosage form does not pass through the gastrointestinal tract-it is absorbed into the bloodstream directly.
Sublingual tablets are intended to be placed under the tongue. Similar to buccal tablets, sublingual tablets are directly absorbed into the bloodstream and bypass the intestines.
Chewable tablets are meant to be chewed before swallowing.
Lozenges and Troches are intended to be dissolved while held in the mouth. This medication form is intended to stay in contact with the throat and mouth over an extended amount of time.
Effervescent tablets release carbon dioxide and rapidly dissolve in water. They should never be swallowed or chewed. They should always be placed in a water and dissolved.
Orally Disintegrating Tablets are tablets that must dissolved on the tongue.
B) Capsules
Capsules are a solid dosage form enclosed in a hard shell or soft gelatin coating. When taken with water, the capsules' coating becomes slippery and easy to swallow.
C) Liquid Oral Dosage Forms
Elixir is a preparation that contains a hydroalcoholic liquid that has a clear color. It is intended to be consumed orally.
Suspension is a preparation that contains tiny particles that are solid. These particles are suspended (not dissolved) in the liquid.
Syrup is a preparation that contains a concentrated sugar solution in water with other active ingredients.
Solution contains ingredients of a medication that are solid. These ingredients are dissolved in the liquid (normally the liquid is water.)
Reconstitution is a medication that is in a powdered form. A suspension is made from this powder by adding a very specific amount of distilled water. It is important to shake the suspension well after adding the water. Some reconstitutions, after adding water, require refrigeration.
Inhalational Dosage Forms
Aerosol spray is a type of dispensing system which creates an aerosol mist of liquid particles. This is used with a can or bottle that contains a liquid under pressure. When the container's valve is opened, the liquid is forced out of a small hole and emerges as an aerosol or mist. As gas expands to drive out the payload, only some propellant evaporates inside the can to maintain an even pressure.
Inhaler or puffer is a medical device used for delivering medication into the body via the lungs. It is mainly used in the treatment of asthma and Chronic Obstructive Pulmonary Disease (COPD). Zanamivir (Relenza), used to treat influenza, must be administered via inhaler.
Nebulizer is a device used to administer medication in the form of a mist inhaled into the lungs. Nebulizers are commonly used for treatment of cystic fibrosis, asthma, COPD and other respiratory diseases.
Parenteral Dosage Forms
Intradermal injections are injections given to a patient in which the goal is to empty the contents of the syringe between the layers of the skin.
Intramuscular (or IM) injection is the injection of a substance directly into a muscle. In medicine, it is one of several alternative methods for the administration of medications (see route of administration). It is used for particular forms of medication that are administered in small amounts. Depending on the chemical properties of the drug, the medication may either be absorbed fairly quickly or more gradually.
Intraosseous infusion (IO) is the process of injection directly into the marrow of a bone. This technique is used in emergency situations to provide fluids and medication when intravenous access is not available or not feasible.
Intraperitoneal(IP) injection is the injection of a substance into the peritoneum (body cavity). IP injection is more often applied to animals than humans. It is generally preferred when large amounts of blood replacement fluids are needed, or when low blood pressure or other problems prevent the use of a suitable blood vessel for intravenous injection.
Intravenous therapy or IV therapy is the giving of substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals. It is commonly referred to as a drip because many systems of administration employ a drip chamber, which prevents air entering the blood stream (air embolism) and allows an estimate of flow rate. Intravenous therapy may be used to correct electrolyte imbalances, to deliver medications, for blood transfusion or as fluid replacement to correct, for example, dehydration.
Subcutaneous(SC) injection is inject into the subcutaneous tissue is a route of administration used for, for example, insulin. Skin popping is a slang term that includes this method of administration, and is usually used in association with recreational drugs.
Topical Dosage Forms
Topical Solutions are applied directly to the skin. The type of solution will affect the absorption rate through the skin, resulting in different dosage strength depending on the form of the solution and how well it gets absorbed through the skin.
Ointments are used topically on the skin to assist in wound healing, to alleviate itchiness or discomfort, or to make the skin feel softer. They are usually of a greasy consistency; and are smooth in texture.
Gels are a solid but malleable mixture that exhibits characteristics of both a liquid and a solid. Wound gels are especially good at helping difficult to heal wounds, such as burns. Gels are good at keeping their form and providing a protective barrier once applied.
Creams are a mixture of oil and water that is used topically and applied to the skin. Oil-water creams are non-greasy and wash away easily, while water-in-oil creams have more of a greasy feeling and are slightly more messy to work with. The benefit of water-in-oil creams is that they can handle drugs that are hydrophobic, and also provide better moisturizing benefits to the skin because the oily layer seals in moisture.
Emulsion is a mixture of any two liquids that won't dissolve into each other and mix together. They can range from a cream to a paste to an orally administered liquid. Calamine lotion is a commonly used emulsion. Emulsions are applied directly onto the skin.
Pledgets are small and absorbent pads used to medicate, protect and help drain a wound or sore. These can be applied directly to the affected area and held in place with gauze or medical tape. The pledget can be used to cover a wound hole to prevent infection and also help protect against pain from incidental contact from clothing and similar items.
Rectal Dosage Forms
Suppositories are small plugs of medication that are designed to melt at body temperature when inserted into the rectum. The method of application is to insert the suppository far enough into the rectum that it will stay there and then simply allow it to melt over time, releasing the medication.
Rectal Creams are designed to be applied specifically to the rectum or rectal area. They are usually greasy and often uncomfortable to use. Hemorrhoids are a common condition that is treated by the use of rectal cream.
Vaginal Dosage Forms
Vaginal Creams are applied via applicator directly to the vagina. The most common use will be to apply before going to sleep, to help allow the cream to stay in place and prevent discharge during daily activities. Vaginal creams can be used to treat vaginal dryness, yeast infections and other infections of the vagina.
Vaginal Suppositories are small plugs of medication, designed to be inserted directly into the vagina. After insertion, they will melt away from the heat of the body and the medicine is delivered as the suppository dissolves. They can be used to treat a variety of gynecological ailments, and usually deliver a numbing or pain relief agent along with the medicine to treat the cause of the infection.
Vaginal Tablets are typically coated in a film, and applied with an applicator. The goal is to place them as far into the vagina as possible, where they will release medicine as they dissolve. Hormones are frequently delivered in this manner, for women needing a treatment that involves a hormone regimen.
Vaginal Rings are flexible rings worn inside the vagina. The typical vaginal ring is worn for 3 weeks before being removed for one week, and then a new ring is inserted after to start the next cycle. The ring slowly delivers hormones into the body to act as a form of birth control. Tests and studies have reported good results and positive feedback from women wearing vaginal rings, and very low instances of issues with the rings either staying inserted properly or falling out.
Ophthalmic Dosage Forms
Ophthalmic Suspensions are a form a mixture where medicine or medicines are suspended in a liquid base and meant to be applied directly to the eye. Treatment of pressure, pain or glaucoma are common things that would be treated with an Ophthalmic suspension.
Ophthalmic Solutions are mostly water-based, and are delivered directly to the eye. Eye drops are a common example of an Ophthalmic solution. Eye drops are usually used to treat symptoms such as dry or red eyes, rather than causes.
Ophthalmic Gels are applied directly to the eye, usually before bedtime. The easiest manner to apply them is to pull the lower eyelid out (creating a pouch) and apply the dose of gel into this pouch. Then close your eyes and roll the eyeball around to spread out the gel. Treating glaucoma is one common use of an Ophthalmic gel.
Ophthalmic Ointments are designed for use around the eyes and are safe enough that incidental contact with the eye itself is acceptable. These can be used to treat or prevent infections in wounds close to the eye.
Otic Dosage Forms
Otic Suspensions are delivered directly into the ear, usually to treat an ear infection. An Otic suspension would also be used in the case of a ruptured eardrum. Typical application is done by having the patient lie on their side with the affected ear turned upwards and the suspension is then allowed to drain directly into the ear.
Otic Solutions are used to treat ear infections. Solutions are often more likely to cause discomfort in the patient, due to a lower pH value than similar suspensions. Application is similar to than of an Otic suspension, the liquid is applied directly into the ear and allowed to drain downward into the affected area.
References:
1. The Theory and practice of Industrial Pharmacy,
(Leon. Lachman, H.A. Lieberman, J.L. Kanig)
2. Dictionary of Pharmaceutical Technology
(Dr. Abu Jamil Ferdous, Dr. Reza Ul-Jamil)
3. Wikipedia
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