In general, immediate release formulations are applied both to classical solid oral dosage forms like tablets, which release the drug in the stomach, and new dosage forms such as orally disintegrating tablets (ODTs) that dissolve in the patient's mouth.
With classical tablets, coatings are usually applied to increase patient compliance by creating a smooth, glossy finish that enables easier swallowing compared with uncoated cores. Coatings can also be applied to make tablets different colours, which help patients to differentiate between tablets when taking multiple medications — a factor that is becoming increasingly important with the ageing population across the globe. In addition, coatings fulfil the fundamental need for mechanical protection of a tablet.ODT formulations have significant potential for enhancing both drug efficacy and patient compliance. An ODT dissolves directly in the saliva, without the need for additional water, which makes them easy to administer and renders the swallowing of unpleasant tablets obsolete. At the same time, the immediate dissolution in the saliva releases the API, which can be directly absorbed by the mucosa. The targeted effect will commence at the earliest point possible.
How has the demand for excipients that enable immediate release changed in recent years? How do you think demand will change in the future and what trends will drive this?
Because of the benefits, demand for immediate release excipients continues to grow. In the future, such excipients will become even more crucial. As well as the already-mentioned ageing population, the benefits relating to improved patient convenience (and hence the greater likelihood of compliance) will drive more pharmaceutical formulators to utilise immediate release excipients for new developments to keep up with competition on the market. Additionally, such excipients can also be used for drug products already available on the market as ODT dosage forms offering new ways of prolonging a product's lifecycle.
Immediate release excipients typically do not negatively impact other tablet properties — they are specifically designed to not interact with active ingredients and to not adversely affect the release profile. In fact, their character targets to improve key properties such as mechanical stability and protection from environmental influences. For example, a coloured film coated with a polymer can protect a sensitive active from degradation through light or oxidation.
Certain excipients are the most (and often only) effective way to achieve a robust and durable tablet while maintaining the immediate release of the active ingredient. For example, when formulating a tablet with hydrophilic pseudoephedrine hydrochloride, a moisture protective coating will prevent the core from unwanted uptake of environmental moisture during storage and handling. Using our Kollicoat Smartseal 30 D, the water uptake of the polymer remains at levels under 5% even at a relative humidity of more than 90%.
What have been the latest innovations in immediate-release excipients, and what are excipient manufacturers working towards in terms of future innovations?
The industry has seen quite an evolution over the past decades when it comes to immediate release coating excipients. The first-generation coating polymer is Hydroxy Propyl Methyl Cellulose (HPMC), but this showed high viscosity and required a plasticiser for formulation. The second generation, Poly Vinyl Alcohol (PVA), brought an improvement in lower viscosity, but still needed a plasticiser.
Recently, a third generation of coating polymers has become available: grafted copolymers with low viscosity and which do not require a plasticiser. The plasticiser function is already built into the grafted copolymer and the low viscosity enables the coating to be made with high amounts of solid content, which leads to a faster and more efficient process.
For ODTs, suppliers have started to offer co-processed excipients that provide desirable properties for the patient, such as fast dissolution and a good mouthfeel.
This trend is expected to be one of the future innovation drivers for excipients suppliers because it provides products that are easier to use and more convenient to handle for formulators, providing valuable improvement in production process robustness and efficiency. Consequently, in the future we will see more co-processed materials and products where certain characteristics are systematically modified.
Jan Bebber is responsible for global marketing of new products, pharma ingredients and services at BASF SE in Ludwigshafen (Germany).