Understanding Pharmaceutical Dosage Forms & Drug Delivery Systems: The Basics

By Nelson LandrauArticle

Types of Dose Forms

In any drug formulation, it is important to use the right pharmaceutical dosage form and drug delivery system to effectively reach the target area in the patient’s body, and in many instances to implement controlled drug release, to ensure the best possible results.

There are many different types of pharmaceutical dosage forms and drug delivery systems in use by the pharmaceutical industry. In this blog from Landrau Scientific Innovations, we’ll take a look at some of the most commonly-used options. Let’s get started.

Gaseous Dose Forms 

This dosage form includes all gaseous drug delivery systems, which commonly include:

  • Gases– This includes inhaled gases such as nitrous oxide and other medicinal gases used for sedation and other medical purposes.
  • Aerodispersions – This refers to products that have a suspension of solid or liquid particles, like inhalation antiasthmatics.
  • Sprays – This includes over-the-counter and prescription nasal sprays and similar products.

Liquid (Aqueous) Dose Forms

Liquid dosages are commonly used and administered in a variety of ways. They can be taken orally, used topically (such as eye drops), or administered intravenously to deliver the Active Pharmaceutical Ingredient (API).

  • Emulsions– An emulsion is a dosage system that consists of two immiscible (non-mixable) liquids, which are finely dispersed throughout a liquid, with the help of thickeners and emulsifiers.
  • Solutions– Unlike emulsions, solutions are in a single homogenous phase, and consist of one or more “solutes” dissolved within a solvent.
  • Suspensions– In this drug delivery system, solid particles are suspended within a liquid phase. This is common for some over-the-counter medicines like antacids and laxatives.

Solid Dose Forms

There are numerous solid dose forms available for modern pharmaceuticals, and it’s important to choose the right one for your drug formulation.

  • Unshaped (powder)– Some medicines may be dispensed in powdered form, and mixed with water or other liquids to create a solution or suspension.
  • Tablet– A tablet dose form consists of an API formulated with fillers, binders, and disentegrants, that has been compressed using a tablet press. The release profile of these dosage forms can be tailored by modifying the tablet formulation or with enteric coatings.
  • Capsule– Capsules consist of an exterior capsule, usually made of gelatin, which holds a powder, coated spheronized drug formulation, liquid, or gelatinous drug. In the tablet with the coated spheronized drug formulation, as the capsule is digested the spheroids are released, but the API is sequestered in the spheroid until the target area is reached, then the drug is released. These types of capsule formulations are very useful for targeted timed-release of the API.
  • Transdermal patches– Transdermal patches are useful for controlled delivery of an API. These drug forms are suitable for use in cases that require timed release of a particular drug such as a contraceptive, or nicotine to assist in smoking cessation.
  • Buccal oral films – These consist of an API formulated into a water-soluble polymer film. These films are designed so that, when wet, they quickly dissolve and release the API to the target area.

Semisolid Dosage Forms

Semisolid dosage forms come in a wide variety of forms. The most common semisolid drug delivery systems include:

  • Ointments– This semisolid dosage form can be hydrocarbon- or water-based. These semi solid dose forms are designed for topical application.
  • Creams– Creams are semi-solid emulsions that can have a water content as high as 85% and as low as 1%.
  • Gels– Gels are a unique semisolid dosage form, where a polymer system holds the liquid form API, providing it with shape and strength. These dose forms are designed for topical application.
  • Pastes– Pastes consist of solid particles that are suspended in an ointment, usually an oleaginous ointment such as petrolatum.
  • Suppositories– Suppositories can be considered a semisolid dosage form. They are made in many different shapes, and intended to melt and release the API at body temperatures, providing sustained release. They can be oleaginous and use an oil base, or use an aqueous base like polyethylene glycol or glycerinated gelatin.

Know The Basics Of Drug Forms & Delivery Systems – And What’s Right For Your Product

At Landrau Scientific Innovations, we specialize in drug formulation – and can handle a wide variety of drug forms and delivery systems like those described in our blog. To learn more about our services and what we can do, feel free to contact us now. We’d be happy to hear from you, learn more about your project, and to help you design the dose form that’s right for your API.