Optimization of the granulation process for designing tablets

Determination of significant factors in high-shear granulation process of sucrose with aqueous solution of sodium lauryl sulphate using partial least square regression approach

Sucrose as one of the most commonly used raw materials in pediatric formulations is soluble and sticky excipient and its manipulation in high shear granulators may be very difficult. Therefore, to determine the correct amount of liquid binder is very important because it falls in a very narrow range and may vary due to small variations in the material properties or environmental conditions. The possibility of using the sugar as powder for granulation may be very challenging because of solubility and moisture adsorption properties of crystalline sugar, especially if the binder solution is water. The aim of this study was trying to solve these problems and produce sucrose granules using high share granulation and water as a binding liquid, with properties required for final product good performance. By reducing the sucrose particle size and improving the uniformity of the size distribution, the differences of the processes of nucleation and growth for small and large particles might be reduced. According to the variable importance or VIP scores from the developed partial least square (PLS) model, raw material particle size is as influential variable as the quantity and composition of the granulation liquid (Gra), granulation time (Grn) and impeller rate (Imp). Keywords: sucrose, particle size distribution, high-shear granulation, partial least square

Optimization of methacrylic acid ester copolymers blends as controlled release coatings using response surface methodology

The aim of this study was to statistically optimize the use of blends of methacrylic acid ester copolymers with different permeability properties as controlled-release coating systems for tablets to produce predictable predesigned release profiles. A full factorial design was used to study and optimize the use of methacrylic acid ester copolymers Eudragit RS 30D and Eudragit RL 30D as coating materials for controlled release. Directly compressed theophylline tablets were coated with aqueous dispersions containing different proportions of the two copolymers using a side-vented coating pan (Accela Cota). The effect of polymer loading level at 5, 7.5, and 10% weight gain and curing time at 50 degrees C for 12 and 24 hours were also evaluated. Coated tablets were tested for their drug release in water using a United States Pharmacopeia (USP) dissolution apparatus #2. The results showed that increasing the content of the lower permeability copolymer Eudragit RS 30D, increasing the polymer load, and increasing curing time at 50 degrees C resulted in slower drug release. A statistical model that describes and predicts the drug release properties of the coated tablets as a function of the copolymers ratio in the coating dispersion, polymer load, and curing time at 50 degrees C was developed. The most significant factor affecting drug release was found to be the ratio of the two copolymers in the coating dispersion followed by the curing time at 50 degrees C and the polymer loading level. Good correlations were observed between the model fitted values andthe experimental values. An optimized formula prepared by superimposing two-dimensional contour plots was prepared; its release profile was found to be in agreement with the prediction obtained from the model.

Process control and scale-up of pharmaceutical wet granulation processes: a review

In this paper the techniques for process control and scale-up of pharmaceutical wet granulation processes are reviewed. For wet granulation in high-shear mixers, specific methods based on the liquid saturation and the consistency of the wet mass are described. Both parameters can be used to quantify the deformability of the wet granules, and relate well with the particle size of the end granules. In practice, the power consumption of the high-shear mixer is used for the monitoring of the wet granulation process, whilst for scale-up, it is helpful to use the underlying relationship between power consumption and saturation level or wet mass consistency. In fluid bed granulation the granulation process is different and the moisture content in the bed is the key parameter to control. This can be monitored directly by near infrared probes or indirectly with temperature probes. As a large number of inter-related variables can be adjusted to modify the process, computerized techniques have become popular for fluid-bed process control--fuzzy logic, neural networks, and models based on experimental design techniques are several examples. In addition, engineering techniques based on particle size population balance modelling are under development for both fluid bed and high-shear granulation.