At present, developing once-daily formulations of compounds which need to be absorbed in the stomach has been a complex and expensive process, involving the use of immediate-release and sustained-release technologies in the same tablet.
Now, UCB has uncovered a formulation approach that allows immediate release of a drug into the stomach, as well as sustained release, using fewer excipient materials than current methods.
The company notes that it can also be used to allow immediate release of one active substance and sustained release of another, something that has been achieved before. "However, these compositions require methods of preparation which are technically very sophisticated and/or do not allow the desired release profiles to be obtained for all the active substances,"notes the patent.
The benefit of rapid absorption in the stomach comes from the quick onset of a drug's therapeutic action - such as pain relief for an analgesic - while sustained release extends the effect over time.
One solution to this long-standing pharmaceutical problem has been to use matrix excipients to enfold the active drug and allow it to diffuse out gradually, and then to use some other form of technology to retain the tablet in the stomach. For example, one approach has been to include a foaming agent that makes the tablet float on the surface of the stomach contents and delay its transit to the intestines.
The drawback of this approach is that the foaming agents tend to be alkaline, and this can impair the delivery of drugs that need the acid environment of the stomach for successful absorption. Moreover, adding both matrix and foaming excipients to the formulation can be costly and make the formulation unfeasible commercially.
UCB's patent describes a way of making a matrix core and coating layer - that require lower quantities of standard matrix excipients. For example, using the formulation to develop a sustained-release formulation of pseudoephedrine resulted in a level of matrix excipient in the tablet of 16 per cent - compared to 40-50 per cent with rival formulations.
The example also shows that the technology allows much smoother and regular delivery of the active substance in a single 120mg formulation than in two 60mg immediate-release gelatine capsules.
The patent notes that the matrix/core formulation is easily tabletted and provides up to 12 hours release from a single dose.