Research
Pharmaceutical Materials Science
As an emerging discipline, pharmaceutical materials science correlates physical properties of active compounds and pharmaceutical ingredients with the performance of the finished dosage product.
Small molecules of pharmaceutical interest can exist in many different forms called morphs, which have different degrees of order at the atomic level. Detection, characterisation and quantification of amorphous, polymorphs and pseudopolymorhs have been recent subjects of research globally.
Drugs in the amorphous or non-crystalline form often have better bioavailability, which can be due to the better dissolution rate compared with their crystalline counterparts. Naturally, the less ordered (amorphous) state does tend to convert into a more stable (crystalline) state of matter. Therefore the efficiency and stability of the final pharmaceutical product often depend on using the correct crystalline or amorphous form of a drug or excipient.
Research in this area focuses on studies of the glass transition phenomenon. Glass-forming materials can be analysed with techniques such as thermal analytical methods, calorimetric methods, crystallography and nuclear magnetic resonance. Although these techniques provide important information about the phase transition processes, new techniques are frequently being used to expand knowledge of existing glass transition processes and to identify previously undetected glass transitions.
Current research focuses on the use and development of thermal analytical techniques. An example is thermally stimulated current spectroscopy (TSC) for the characterisation and design of drugs and drug delivery systems. These include amorphous and polymorphic drugs and mainly polymeric delivery systems.
In respect of glass-forming materials, interest lies in understanding the cooperative rearrangements within the system. These can be studied by assessing the distribution of the relaxation process, using relaxation map analysis. In addition, thermal analytical methods have been used to investigate correlation between empirical parameters of the glass-forming systems such as the fragility index and its chemical structure.
The interest in physico-chemical properties of drugs and dosage forms includes research of stability assessments and prediction. Of particular interest is exploring kinetics and degradation pathways of light-sensitive pharmaceutical compounds. Recent research has therefore investigated the problems of characterising amorphous materials and understanding stability of pharmaceutical active compounds and end products.
This has led to considerable expertise in the following analytical techniques: ultra-violet-visible spectroscopy (UV/VIS), infra-red spectroscopy (IR), high-perfomance liquid chromatography (HPLC), HPLC/mass spectroscopy (HPLC/MS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), modulated temperature DSC, hot stage microscopy (HSM) and thermally stimulated current spectroscopy (TSC).
| Dr Milan Antonijevic | Telephone: 0208 331 9841 | Email: m.antonijevic@gre.ac.uk |