Powder blending HPLC

The raw material is not available. Therefore the pharmacist decides to prepare capsules from Procoralan tablets. These tablets have a coating, but one without modified-release properties. Ivabradine has a high aqueous solubility and high membrane permeability (BCS class 1), and thus the pharmacist disregards the coating. He mixes the ground tablets with lactose monohydrate and fills capsules with the powder blend. Product control shows that the preparatimi complies with requirements for uniformity of mass and deviation of the theoretical weight. Post-preparation analysis by HPLC with diode array detection shows a mean content within the acceptable limits (90-100 %) and a proper content uniformity. 

Both Littringer et al. and Monckedieck et al. [11, 33] were sampling the powder blends ten times with a spatula. Three samples were drawn from the top, four from the centre and three from the bottom of the vessel. The samples were dissolved in solvent and analysed by reversed phase high-performance liquid chromatography (RP-HPLC). The coefficients of variation (CV) of the content as well as the recovery were calculated in order to determine the homogeneity. CV was required to be lower than 5 % while recovery needed to be larger than 95 % [11]. 

The objective of blend analysis is to determine whether the blend is uniformly mixed or not (very similar to CU, except BU is for powders and CU is for dosage units). What one needs is quick answers during blend analysis, so fast and simple methods are preferable. There is no need to develop a new HPLC method for blend analysis, since the CU method can easily be employed here. 

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