Oral solid dosage
Most medicines, from over the counter treatments to prescription drugs, are taken by mouth in the form of tablets and capsules. Oral medicines are convenient, flexible and cost-effective. They can be produced in large numbers very fast (production rates of 1 million per hour can be achieved). Variants that are precisely suited to individual preferences and needs can easily be developed.
Direct compression is the simplest form of oral dosage production as it contains the fewest process stages, leading to a shorter process cycle and faster production times.
Dry granulation is a simple and low cost method, once extremely common and again becoming more popular because of its simplicity and cost efficiency. Dry Granulation helps to increase the size of granules within powders, making it easier to form them into tablets or capsules. It also leads to dense and stable formulations for use in filling capsules.
This is perhaps the most popular method for tablet production because it can be applied to almost any dosage of any drug. Wet granulation of powders improves flow and compactability of the compression mix, and this is the key to its popularity.
Extrusion spheranisation is similar in almost every respect to Wet Granulation, following similar process stages. The difference are the extra stages for shaping the processed materials, typically for use in capsules that deliver active ingredients on a timed basis.
Hard gelatin capsules are a common oral solid dosage for immediate release formulations. Compared to tablets they are easy to formulate and manufacture, formulations can be developed with minimal amounts of active pharmaceutical ingredient (API) and they are easily blinded for clinical trial purposes. Additionally they provide a ready means of identification through the choice of capsule shell colour and printing, and they are patient friendly being easy to swallow and providing taste masking for unpleasant actives.
Patients can now choose between orally disintegrating tablets, timed release capsules and pills of different shapes, sizes and flavours. The range and variety of available solid dose options makes it possible to respond rapidly and creatively to changing user preferences and market needs.
Role of excipients
Both the efficiency of production and effectiveness of drug delivery depend on the excipients used to mix with the active ingredients. Not only must the blend of active ingredients and excipients deliver the treatment exactly as planned and predicted, it must also compress into the right shape and size, forming pills, tablets and capsules that are fit for purpose and can be produced efficiently.
Different techniques are used to form an effective compression mix that, after processing, will provide the predicted performance in terms of flow and release of active ingredients. Each of the available techniques has advantages and disadvantages, related to number of processes, cost of materials and resources, speed and, above all, the performance characteristics you wish to achieve.
To make valid comparisons and ensure best possible decision-making, a number of different factors must be taken into consideration. These include:
- Drug properties: what is the dosage? Granulation will work better than direct compression for high and low doses. How important is stability? This may indicate the need to use dry granulation or direct compression. Physical and chemical characteristics? Factors such as solubility and melting point will guide you to one technique rather than another.
- Drug availability: when developing new drugs quantities may be low and this could lead you to a low cost option (normally direct compression).
- Preference: different companies and different formulators have their own preferred way of doing things. Different product variants will also influence the choice of technique. If there is an exceptional need for stability and security, this is a good indicator for use of wet granulation, which is a more robust, but less cost-effective technique.
- Cost: it is essential to strike the right balance between extra process stages and use of energy (in wet granulation) and additional excipient costs (direct compression). Continuous processing is also a factor here.
There are a number of moving parts in making these calculations, and the outcomes will vary depending on many different factors. To start a dialogue with our technical experts and ensure best possible decision-making make direct contact today.