287728 Solvent Penetration Rate in Tablet Measurement Using Video Image Processing

Monday, October 29, 2012
Hall B (Convention Center )
Dan Braido1, Yuriy Gulak2 and Alberto Cuitino2, (1)Rutgers University, Piscataway, NJ, (2)Mechanical and Aerospace Engineering, Rutgers University, Piscataway, NJ

Solvent Penetration Rate in Tablet Measurement Using Video Image Processing


The performance of drug delivery systems, such as pharmaceutical tablets, is usually quantified by the dissolution rates required to maintain the desired active ingredients concentration in the gastrointestinal tract.  Whether or not the tablet matrix disintegrates, the rate at which solvent penetrates the matrix can be highly influential in terms of the drug release rate as well as the total drug released.  Therefore, experimental measurements of the velocity of the liquid front are needed in order to adjust or optimize the product performance. In addition, such measurements can help us understand the diffusion mechanism for a particular solvent - tablet matrix combination.  We seek to validate a low cost method for determination of solvent penetration in tablets and evaluate the performance of numerical modeling of this penetration.


Tablet composed of spray dried lactose are manually compressed to produce samples with equivalent pore structures.  Solvent is then deposited atop sample tablets and the process of solvent penetration into the matrix is recorded using a GimaGo GO443C camera.  Using OPENCV, the videos are processed such that the solvent fronts are isolated and their progress tracked.  The process is repeated for tablets made of a pharmaceutical blend.  The resulting progress of the solvent through the polymer matrices are compared to the Washburn and molecular sorption models.


Solvent front propagation as captured by the video processing technique shows the effective fit of the system to the Washburn and molecular sorption models to tablets of pure lactose as shown in Figure 1a.    

Figure 1: Model fits for (a)lactose tablets,   tablets of low (b) and high (c) total strain blends.

Figure 1 b and c shows the evolution of the solvent front and associated models in tablets made from model pharmaceutical blends.


We have presented an experimental technique for the measurement of the solvent/water penetration in immediate release tablets using digital video image processing which may be useful if many tablets have to be processed and their absorption ability compared.  The solvent penetration results of a simple system fit well with the molecular sorption model proposed by Vesely, however, the lack of direct correlation of the coefficients with actual physical parameters limits the insights which can be gleaned from this model.  The more complex systems produce more variable results.  For tablets made from more complex powder blends, the mechanisms governing penetration are not completely incorporated in either model utilized herein.

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