What Is Solid Dosage?

Because of its ease of access and administration, a solid dosage is deemed as the most convenient form of medication used today. It also offers better solubility and stability which can be considered an important factor in pharmaceuticals.

Due to its popularity, most medicines sold over-the-counter come in this form of dosage. This makes the manufacturing process very critical as it would mean life or death for those who take the medication they produce. Proper solid dose training in all necessary processes should be taken before venturing into this kind of business.

Solid Dose: Active Ingredients and Excipients

Like other forms of dosage, an oral solid dose drug contains at least one active ingredient and several excipients. Active ingredients, also known as API (active pharmaceutical ingredients), are those that actually work on treating a condition or illness. For example, the active ingredient in Coumadin is warfarin, an anti-coagulant substance or blood-thinner. Other drugs contain more than one active ingredient.

Meanwhile, excipients are substances that support the active ingredient encapsulated or added to the tablet mixture. These materials, while inert, act in a way that will improve the delivery and efficacy of an active ingredient.

Some of the well-known excipients used in OSDs like tablets and capsules are binders, vehicles, diluents, disintegrants, lubricants, gliders, and many more.

Binders combine the ingredients with mechanical strength. In place of this substance, some manufacturers use compression aids and granulating agents, depending on the form of OSD they are producing. Meanwhile, disintegrants enable the release of active ingredients through the dissolution of the OSD. This substance typically acts when the tablet or capsule is already traveling down the digestive tract.

A diluent provides more body or "bulk" to the tablet while enabling active ingredients' accurate dosing. Some of the most common examples of diluents are the sugar compounds glucose, sucrose, lactose, dextrin, and sorbitol as well as inorganic materials like magnesium salt, silicates, calcium, and potassium or sodium chloride.

Lubricants and glidants improve the flow of active ingredients. However, the former promotes slower dissolution and disintegration of OSDs, which is usually perfect for lozenges and pastilles.

Tablet coating, as the name suggests, covers the OSD from air, light, and moisture from the environment and improves its mechanical strength. It is also used to mask the tablet's taste and/or smell for easier swallowing and may contain other agents.

Coloring agents are considered additional excipients for better drug identification. They are also incorporated in many well-known brands to combat counterfeits while improving the stability of medications that are sensitive to light.

Solid Dosage Manufacturing Process

Learning about solid dose manufacturing requires at least two days of training. After that, you may need a lot more practice to perfect it. Some of the main processes you should know about in solid dose manufacturing are the formulation, granulation, milling, blending, tableting, coating, and encapsulating.

The formulation is the process where a manufacturer comes up with a combination of active ingredients and excipients to add to his product. Some important things to remember at this stage is careful consideration of adverse reaction between substances added as well as the benefits they provide.

Meanwhile, granulation comes in two forms: the wet granulation and dry granulation. The wet granulation involves the nucleation mechanism, transition to the funicular and capillary stage, and ball growth. Dry granulation — a.k.a. "slugging"— is used when some of the materials are sensitive to moisture and/or heat. Some manufacturers also use this method to control dust and bulk density.

Milling is done in one or more unit processes to achieve better flow. It is also used to prevent "fines" that can damage tablet press machines when mixed with oil and moisture.

The OSD manufacturing process also includes blending where ideal powder flow, compaction, tensile strength, and vertical shear are monitored. The final blend should be uniform to maintain the tablet's potency.

Finally, OSD manufacturing also involves tableting where final blends of granules are pressed into molds to become tablets; coating which is done to provide additional mechanical strength to the tablet; and encapsulating where granules are filled into gelatin capsules.