The Valedictory speaker at Pharma LabNext Conclave 2021 was Dr Raj Suryanarayanan, Professor and William & Mildred Peters Endowed Chair, Department of Pharmaceutics, College of Pharmacy, University of Minnesota. His research focuses on how to apply principles of pharma materials science to the design of robust pharma dosage forms with reproducible and predictable properties. At the event, he spoke on recent advances in the solid-state drug product characterization.
He gave a technical presentation on the various classes of drugs in the market and pointed out that there is a challenge with solubility that needs to be tackled. He gave details about different kinds of compounds and their characteristics. He said that changing compounds from crystalline to amorphous you can get better solubility and bioavailability. However, the change from amorphous to crystalline form of drugs leads to a loss in bioavailability. He cautioned that if sufficient care is not taken, the amorphous drugs will convert to crystalline, and the products might have to be recalled from the market. He also explained the limitation of the amorphous form and said that it is intrinsically unstable.
He said that about 50 per cent of all drug molecules are administered as salts. Dissolution rate, bioavailability and solubility are some of the advantages of salt formation. He elaborated on factors causing disproportionation of drugs include excipients, humidity, temperature and mechanical activation/processing parameters, citing examples of several drugs and their compositions to explain his points.
He went on to explain various analytical methods used in the pharma industry such as HPLC, powder X-ray diffractometry, spectroscopic techniques like IR, RAMAN and solid state NMR, calorimetry, etc.
Thus, the presentation looked at in-situ phase transformation to provide critical spatial information and offer mechanistic insight of phase transformation for rational selection of excipients. A key take away from the session was that since the surface of a tablet is in contact with the external environment, the formulator has to be very careful. The surface composition and microstructure can play a disproportionate role on product properties and performance.
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