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Browsing by Subject "weight variation"

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  • Hämäläinen, Noora (2021)
    Mini-tablets are 1-3 mm in diameter and administered as a single tablet or as a multi-particulate formulation. Mini-tablets are an attractive alternative for conventional solid dosage forms due to the ease of administration and the possibility for combination and individualised drug therapy. In mini-tablet production, good flowability of the formulation is critical as minor variations in die filling can lead to significant changes in mini-tablet weights. In addition, to reduce weight variation, the particle size should not exceed 1/3rd of the die diameter. This study aimed to determine the influence of the granule size on mini-tablet weight variability and content uniformity. The feasibility of direct compression, as well as high-shear wet granulated and roller-compacted formulations, were evaluated. From the nine final formulations manufactured, particle size distribution, Hausner ratio, Carr’s index, angle of repose and flowability were determined. The mini-tablets were made on a rotary tablet press using single punches of 3 mm in diameter. Content uniformity and weight variation of the mini-tablets were determined. The direct compression formulation had the smallest particle size, and the roller-compacted formulation milled through a 1.0 mm and 1.25 mm square screen had the largest particle size. Surprisingly, the RC 0.8 mm grater screen formulation had a very wide particle size distribution and is classified as a very fine blend. The wide particle size distribution might result from a high fill ratio during the milling of the roller-compacted ribbons. The four different high-shear wet granule formulations had a very similar particle size distribution. According to the Hausner ratio and Carr’s index values, the flow properties of the formulations varied between fair and very poor, while according to the angle of repose, the flow properties were between excellent and poor. However, all nine formulations were used to make mini-tablets with acceptable uniformity of mass, mini-tablets were within ± 8 % of the target weight, and none exceeded the 10 % limit set by Ph. Eur. The weight variation is small, as indicated by the low RSD of 1.0-2.9 %. The differences in the weight variation may be attributed to segregation due to particle or granule size and density. This is further supported by the fact that no force feeder or vacuum was utilised in the rotary tablet press, possibly causing re-circulation of the formulation and shearing forces. In addition, the fill level of the feeder might have varied between the nine formulations and affect the weight variation in a way that is not recognised in this study. Only direct compression formulation was within the limits of uniformity of content of single-dose preparations set by Ph. Eur. In the final formulations, the amount of paracetamol was in the HSWG 0.8 mm round screen 98.5 % and in the RC 1.0 mm square screen 97.7 %. These results suggest that the formulations contained an adequate amount of paracetamol, which does not explain why the mini-tablets made from high-shear wet granules did not meet the content uniformity criteria. Furthermore, the weight variation might not entirely explain why high-shear wet granulated formulations performed so poorly in the content uniformity analysis. In summary, that direct compression is a feasible manufacturing method for mini-tablets of 3 mm in diameter. However, further studies are needed on the content uniformity of mini-tablets made using high-shear wet granulated and roller-compacted formulations as these did not meet the content uniformity criterion. In particular, the content uniformity of the mini-tablets made from the high-shear wet granulated formulations was not acceptable, and the reason for this was not identified.