Advantages of Liquid-fill Encapsulation
Liquid-fill encapsulation using hard-shell capsules is becoming an increasingly used vehicle for oral drug delivery, especially for molecules that exhibit poor aqueous solubility or are highly potent.
Tillotts Services has over 26 years experience of developing new liquid-fill formulations and filling a variety of different liquids and semi-solids into two-piece, hard-shell capsules (Gelatine, HPMC, etc.).
For liquids with a viscosity lower than 15 mPa/s these can be filled into hard gelatine capsules which are then sealed within a few seconds. This prevents leaking and the visible band acts as a tamper-proof mechanism.
For paste (semi-liquid) formulations, there are two different approaches that we commonly use within Tillotts Services:
- Thixotropic formulation (in quiescent condition the substance is solid and becomes a liquid when stirred); this can be achieved with a mixture of a liquid and thickening agent.
- Thermoplastic formulation (substance is liquid when heated and solidifies again at room temperature). Thermoresistent solid substances can be heated up to 75 deg.C for liquid-filling and then cooled to room temperature.
Liquid-fill encapsulation using hard-gelatine capsules has several benefits over soft gelatine capsules as summarised below: