Effect of crospovidone and hydroxypropyl cellulose on carbamazepine in high-dose tablet formulation

Setting up multivariate specifications on critical raw material attributes to ensure consistent drug dissolution from high drug-load sustained-release matrix tablet

The purpose of this study was to describe the raw material variability that influenced the in-vitro dissolution behavior of high drug-load sustained-release matrix tablet and to ensure the consistent quality of the final product. The Panax notoginseng saponins (PNS) - hydroxypropyl methylcellulose - anhydrous lactose - magnesium stearate (57:20:23:0.5%, w/w) was used as the model formulation. PNS extract powders with lot-to-lot and source-to-source differences were collected to cover the common cause variations and their physicochemical properties were characterized by the chromatographic fingerprints and the SeDeM expert system. It was found that the release behavior of active pharmaceutical ingredients (APIs) in PNS from different batches exhibited considerable variations. Latent variable modeling results demonstrated that the physical properties of raw materials played major roles in predicting the drug dissolution. PNS extracts with high specific surface area, the width of particle size distribution and hygroscopicity or low moisture content led to an increase in drug release. In order to perform efficient pass/fail judgments for incoming new materials, multivariate specifications of critical material attributes (CMAs) were established and the multivariate design space in line with the quality by design (QbD) principles was explored to achieve the release target.

Recrystallization of commercial carbamazepine samples-a strategy to control dissolution variability

Physical properties of commercial carbamazepine (CBZ) samples can significantly influence drug release and thereby jeopardize bioequivalence of the final dosage form. The aim of this study was to reduce variability in commercial CBZ samples by recrystallization. CBZ samples of four different suppliers were recrystallized in ethanol solution containing 1% polyvinylpyrrolidone (PVP). CBZ samples were analyzed by disk intrinsic dissolution rate (DIDR), X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Recrystallized CBZ samples showed strongly reduced variability in DIDR compared to the untreated CBZ samples. Moreover, transformation process to CBZ dihydrate was inhibited; no dihydrate crystals were visible on compact surfaces after 8 h intrinsic dissolution measurement. Recrystallized CBZ samples showed no change in polymorphic form, however, particle size and shape was inhomogenous. In binary mixtures with microcrystalline cellulose, recrystallized CBZ samples again showed difference in drug release. This difference was associated with the inhomogenous particle size in the recrystallized CBZ samples. The results show that a controlled grinding step is required after recrystallization. We suggest the recrystallization in presence of 1% PVP followed by a controlled grinding step as a strategy to reduce dissolution variability in commercial CBZ samples.