Applications of Fourier transform infrared spectroscopic imaging to tablet dissolution and drug release.

INTRODUCTION: Solid oral dosage forms are the most commonly used method for administering active pharmaceutical ingredients to patients. Understanding the mechanisms and processes of drug release is essential for improving the design of pharmaceutical tablets. AREAS COVERED: In this review, recent approaches where attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic imaging has been applied to study tablet dissolution and drug release have been investigated. Drug release studies of model pharmaceutical systems composed of drug/polymer mixtures in the presence of aqueous solutions have been discussed, as has the subsequent combination with UV/Vis spectroscopic detection to quantify the amount of drug dissolved as a function of time. The use of a single-reflection ATR accessory with a diamond crystal allows for in situ FTIR imaging of tablet compaction and dissolution. EXPERT OPINION: ATR-FTIR imaging can address the challenges of investigating the mechanisms of drug release from a range of innovative new delivery systems. Unlike standard dissolution tests, this spectroscopic imaging method obtains insight and information about changes within the tablet during dissolution. Areas where ATR-FTIR imaging has shown further potential to be particularly useful are for the study of multi-layered solid tablets, high-throughput analysis, use of microfluidic devices and for surface-enhanced ATR-FTIR spectroscopy.