2.3. Different types of medications1. Liquid: – different types of liquid medications Show
o – Solution – a liquid containing dissolved medication 2. Solid: – Tablet/caplet Enteric-coated tablet o Hard, compressed medication in a round, oval, or square shape o Some have an enteric coating or other types of coatings, which delay the release of the drug and cannot be crushed or chewed 3. Semi-solid: o Capsule In a gelatin container that may be hard or soft. Dissolves quickly in the stomach; o Capsule -a capsule that when swallowed releases one or more medicinal drugs over a set period; o Suppository Small solid medicated substance, usually cone-shaped Melts at body temperature. May be administered by rectum or vagina Refrigerate as directed by the manufacturer. 4. Topical medications applied directly to the skin surface. Topical medications include the following: o. Ointment -a semisolid substance for application of medication to the skin or eye o Paste – a semisolid substance thicker and stiffer than an ointment containing medications o Cream – semisolid preparation holding medication so it can be applied to the skin o Shampoo – a liquid containing medication that is applied to the scalp and hair o Patches (transdermal) – medication encased in a round, square, or oval disc that is affixed to the skin o Powder – fine, ground form of medication that may be used to be swallowed, or may be used as on the skin for rashes o Aerosol sprays – a solution that holds the medication suspended until it is dispensed in the form of a mist to spray on the skin o Inhalant- Medication carried into the respiratory tract using air, oxygen or steam Inhalants may be used orally or nasally Introduction to Liquid Dosage FormsAs part of the PTCB exam, students are expected to have a thorough knowledge of dosage forms. We have already talked about solid dosage forms – such as tablets and capsules. Today, we review the most common liquid dosage forms. We have all, at some point, used a liquid dosage form. Whether it is a cough medicine or gargling a solution to relieve symptoms affecting the back of the throat – liquid dosage forms are widespread and ubiquitous. As a pharmacy technician, you will be handling these medicines on a daily basis. Among the many different liquid dosage forms, here are some of the most common:
If you have taken some PTCB practice tests in the past, you may have come across questions on liquid dosage forms. Furthermore, you can expect some questions on dosage forms to appear on the PTCB test. With dosage forms, there is a lot to learn. But here, we have covered the broad, essential knowledge that students are expected to know and the most common facts that get tested. Advantages / Disadvantages of Liquid Dosage FormsAdvantages of liquid dosage forms include:
However, like any dosage form, liquid formulations are not without their disadvantages. Disadvantages include:
Liquid formulations are structured in the same way as most other medicines – namely, that there is a small amount of active ingredient (drug) dispersed throughout a larger medium. In the case of liquid formulations, active ingredient is dispersed throughout a vehicle. Note – one of the most common kinds of PTCB exam question is to ask about excipients. This includes vehicles. It is important that students understand the definitions and differences between each kind of excipient! This “vehicle” could be sugar-based – for example: this is the case with many liquid cough medicines. Children find it easier to ingest cough medicines because of flavoring agents that have been added. The sweetness of the vehicle also helps too. As we have learned, this is not the case with other dosage forms, such as solid or semisolid dosage forms. There are two ways the drug interacts with the vehicle:
The risk with fine particles is that when the medicine is left stationary in a cupboard or fridge, the fine particles settle to the bottom – forming a kind of cake. That is why it is important to counsel patients to shake the bottle before use. It re-disperses fine particles throughout the vehicle, allowing for more equal dosing. SolutionsSolutions contain solutes (dissolved medicines) within a solvent (liquid vehicle). The dispersion of the solution is equal. This contrasts with a suspension where it is an unequal distribution of fine particles that are not dissolved. With solutions, active ingredient is quickly absorbed – whether it be on the skin, through the gastrointestinal tract, or at another site of administration – including the rectal route. Aqueous solutions have water as the solvent. Examples include:
Thicker aqueous solutions include syrups – which are a mixture of sugar solution and drug. Non-Aqueous SolutionsThere are two primary kinds of non-aqueous solution:
Elixirs are sweetened hydro-alcoholic solutions that taste good, are relatively stable, and which are easy to prepare. The concentration of alcohol is typically between 3 percent and 25 percent. Tinctures have a much higher alcohol content than elixirs. For example: tincture of iodine. Alcohol levels are typically between 25 percent and 60 percent, though in some cases this is higher. In the case of tincture of iodine, it has 50 percent alcohol content. Liquids with Insoluble MatterSome liquid solutions have insoluble matter dispersed throughout the vehicle. Examples include:
As the word suggests, suspensions have particles of drug suspended within the vehicle. If the bottle is not shaken before use, the patient receives only a dose of the vehicle – and almost none of the active ingredient. Drugs that readily dissolve in a vehicle are said to have a high solubility. Suspensions have a low solubility because the drug fails to completely dissolve in the vehicle. Instead, particles remain dispersed. Suspensions are available for oral, topical, and injectable use. An example of an oral suspension is amoxicillin 125-500mg of drug per 5mL of dose (teaspoon) of medicine. In the case of injectable suspensions (such as Kenalog-40), they allow for insoluble drugs to be administered to the body in subcutaneous or intramuscular (IM) form. Injectable suspensions are also used for the purposes of depot injections – where the drug is released over a prolonged period (example: Procaine Penicillin G). Characteristics of the ideal suspension include:
Emulsions are mixtures that contain two kinds of liquid that do not usually mix. For example – oil and water do not mix. But, in an emulsion, it can be created in such a way as to keep the mixture together as much as possible. This is due to the presence of an excipient called an emulsifying agent. Examples of emulsifying agents include:
ConclusionThe new 2020 syllabus released by PTCB mention dosage forms as a core subject to prepare for the exam. Here, we have broadly covered the liquid dosage forms part of the syllabus. Of course, there are many other dosage forms to learn about – including solid dosage forms and semisolid dosage forms, amongst others. Learning about these dosage forms is important. Not only do these questions get asked on PTCB practice exams, but they also appear on the real thing. The more questions you practice, the better you can plug knowledge gaps and dominate topics on the day of your exam. Furthermore, it adds to your future professional knowledge. Pharmacy technicians handle many different dosage forms daily. It is important for technicians to understand the many key differences between these dosage forms and why one dosage form may be used rather than another form. Check back to our PTCB Test Prep blog soon for more content to help you master the 2020 PTCB exam. What is a drug dissolved in a solution of water alcohol and sugar called?Tincture. A drug dissolved in an alcohol solution; e.g., tincture of iodine. Elixir. A drug dissolved in a solution of water, alcohol, and sugar; e.g., terpin hydrate elixir.
What is a liquid medication that is combined with alcohol?In an elixir, the active ingredients are mixed with a liquid, usually a kind of syrup or alcohol, in which they can dissolve.
Which term describes drugs that are able to dissolve in liquids?Solubility is the ability for a drug to be dissolved in an aqueous medium. Drug solubility is defined as the maximum concentration of a substance that can be completely dissolved in a given solvent at a certain temperature and pressure level.
What is an aqueous liquid preparation called that contains one or more substances that are completely dissolved?powders. Aqueous liquid preparation containing one or more substances completely dissolved. Every solution has two parts: the solute(the dissolved substance) and the solvent(the substance, usually a liquid, in which the solute is dissolved. solutions. Alcoholic solutions of volatile substances.
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