Simultaneous FTIR Spectroscopic Imaging and Visible Photography to Monitor Tablet Dissolution and Drug Release

Abstract

A method to study tablet dissolution simultaneously by Fourier transform infraredattenuated total reflection (FTIR-ATR) imaging and macro-photography is described. Such a combined approach appeared important as the results of macro-photography, which have been provided by a number of authors, led to contradictory interpretations. The macro-photographs of a pharmaceutical tablet during exposure to water show a number of 'fronts' moving into the tablet. These fronts are obviously related to water penetration into and dissolution of the tablet, but the exact nature can not be derived from photographic evidence. Therefore, the combination of macro-photography and FTIR-ATR imaging was developed and used to interpret the physical changes leading to the observed fronts. The quantitative results obtained by FTIR-ATR imaging enabled the attribution of the three observed fronts (inside to outside) to: 1. True water penetration, possibly combined with (partial) dissolution of buflomedyl pyridoxal phosphate (BPP) 2. Total gellification of hydroxypropyl-methylcellulose (HPMC) 3. Erosion front IntroductionIn recent years, a number of new approaches has been reported to study the behaviour of pharmaceutical tablets during dissolution. These studies aim to generate an understanding of the processes in a dissolving tablet. This is a welcome addition to the standard dissolution tests, which obtain the amount of dissolved active ingredient as a function of time, but do not provide indications on the underlying mechanisms of tablet dissolution.

Applications of FTIR Spectroscopic Imaging in Pharmaceutical Science

“…Macro-ATR-FTIR imaging without the use of an IR microscope facilitates the imaging of greater fields of view and opens a range of possibilities for studying large areas or whole tablets and the analysis of many samples in a high-throughput manner. The main advantage of ATR-FTIR imaging is its suitability for studying aqueous systems, which is crucial for in situ dissolution analysis [7][8][9]. This chapter will examine many applications of macro-ATR-FTIR imaging, mostly pioneered in our group.…”

Application of FTIR Spectroscopic Imaging to Study the Effects of Modifying the pH Microenvironment on the Dissolution of Ibuprofen from HPMC Matrices

“…Visible optical video analysis was used, similar to that introduced previously, 32 to study retention of the pHmodifying compounds in the matrix during dissolution. A transparent perspex dissolution cell was used, as schematically shown in Figure 1a.…”

“…31 A visibly transparent dissolution cell has also been employed, allowing the collection of both FTIR and optical visible images simultaneously from the same system. 32 As FTIR imaging is both chemically and spatially specific, it is possible to track the dissolution of domains of the drugs within the matrix. This work demonstrates the applicability of FTIR imaging to study the dissolution of drugs from tablet matrices containing pH modifiers.…”

High-amylose carboxymethyl starch matrices for oral sustained drug-release: In vitro and in vivo evaluation

“…A large spectrum of mathematical models describing drug-release from the hydrophilic matrix tablets has been developed. These models try to include many parameters that affect drug-release and kinetics, such as the thickness of the gel layer and the position of the different fronts Kazarian and van der Weerd 2008), the presence of different excipients (Pillay and Fassihi 2000;Baumgartner, Pavli et al 2008), the properties of the selected polymer and drug (Talukdar, Michoel et al 1996;Saša, Odon et al 2006;Ferrero, Massuelle et al 2010), the polymer concentration across the gel, the mesh size of the polymeric network (Baumgartner, Kristl et al 2002), and so on. However, in many cases, the use of a simple empirical or semiempirical model is sufficient (Siepmann and Peppas 2001).…”