Quality by design: understanding the formulation variables and optimization of metformin hydrochloride 750 mg sustained release tablet by Box–Behnken design

A formulation development strategy for dual-release bilayer tablets: An integrated approach of quality by design and a placebo layer

Although dual-release mechanism bilayer tablets containing one drug in both immediate- and sustained-release layers are widely used to improve therapeutic efficiency, studies quantitatively analyzing the drug amount released from each layer and the mutual effect of each layer's mechanical properties on drug product quality are limited. Here, the formulation of a dual-release bilayer tablet containing sarpogrelate HCl was optimized with a placebo layer and quality by design (QbD) approach. The placebo layer was developed to replace the active pharmaceutical ingredient and its mechanical properties were evaluated. The formulation was developed using the placebo layer to quantitatively analyze the drug released from each layer. The mixture design and Monte Carlo simulation enabled robust design space identification. The mutual effect of each layer's mechanical properties on drug product quality was confirmed by multivariate analysis using the optimal settings in the design space. The optimized formulation was characterized by comparison with a reference drug for various quality attributes and in vivo pharmacokinetic parameters, which ensured the bioequivalence of the optimized bilayer tablet with the reference drug. This study shows that the integration of QbD and a placebo layer is an effective optimization strategy for dual-release bilayer tablets containing one drug in different layers.

Effects of granulation process variables on the physical properties of dosage forms by combination of experimental design and principal component analysis

The current study was to understand how process variables of high shear wet granulations affect physical properties of granules and tablets. The knowledge gained was intended to be used for Quality-by-Design based process design and optimization. The variables were selected based on the risk assessment as impeller speed, liquid addition rate, and wet massing time. Formulation compositions were kept constant to minimize their influence on granules properties. Multiple linear regression models were built providing understanding of the impact of each variable on granule hardness, Carr's index, tablet tensile strength, surface mean diameter of granules, and compression behavior. The experimental results showed that the impact of impeller speed was more dominant compared to wet massing time and water addition rate. The results also revealed that quality of granules and tablets could be optimized by adjusting specific process variables (impeller speed 1193 rpm, water spray rate 3.7 ml/min, and wet massing time 2.84 min). Overall desirability was 0.84 suggesting that the response values were closer to the target one. The SEM image of granules showed that spherical and smooth granules produced at higher impeller speed, whereas rough and irregular shape granules at lower speed. Moreover, multivariate data analysis demonstrated that impeller speed and massing time had strong correlation with the granule and tablet properties. In overall, the combined experimental design and principal component analysis approach allowed to better understand the correlation between process variables and granules and tablet attributes.

Quality-by-design approach for the development of telmisartan potassium tablets

A quality-by-design approach was adopted to develop telmisartan potassium (TP) tablets, which were bioequivalent with the commercially available Micardis^® (telmisartan free base) tablets. The dissolution pattern and impurity profile of TP tablets differed from those of Micardis^® tablets because telmisartan free base is poorly soluble in water. After identifying the quality target product profile and critical quality attributes (CQAs), drug dissolution, and impurities were predicted to be risky CQAs. To determine the exact range and cause of risks, we used the risk assessment (RA) tools, preliminary hazard analysis and failure mode and effect analysis to determine the parameters affecting drug dissolution, impurities, and formulation. The range of the design space was optimized using the face-centered central composite design among the design of experiment (DOE) methods. The binder, disintegrant, and kneading time in the wet granulation were identified as X values affecting Y values (disintegration, hardness, friability, dissolution, and impurities). After determining the design space with the desired Y values, the TP tablets were formulated and their dissolution pattern was compared with that of the reference tablet. The selected TP tablet formulated using design space showed a similar dissolution to that of Micardis^® tablets at pH 7.5. The QbD approach TP tablet was bioequivalent to Micardis^® tablets in beagle dogs.