Quantitation of trace amorphous solifenacin succinate in pharmaceutical formulations by transmission Raman spectroscopy

Effects of wet granulation process variables on the quantitative assay model of transmission Raman spectroscopy for pharmaceutical tablets

Transmission Raman spectroscopy (TRS) is a process analytical technology tool for nondestructive analysis of drug content in tablets. Although wet granulation is the most used tablet manufacturing method, most TRS studies have focused on tablets manufactured via direct compression. The effects of upstream process parameter variations, such as granulation, on the prediction performance of TRS quantitative models are unknown. We evaluated the effects of process parameter variations during granulation on the prediction performance of the TRS quantitative model. Tablets with a drug concentration of 1%w/w were used. We developed PLS calibration models for the drug concentration range of 70-130% label claims. Subsequently, we predicted the drug content of the tablets with different granulation parameters. The results of our study demonstrate that the variation in the predicted recovery due to the variation in granulation parameters was practically acceptable. The calibration model showed a good prediction performance for tablets manufactured at different granulation scales and thicknesses. Therefore, we conclude that TRS quantitative models are robust to variations in upstream processes, such as granulation and downstream variations in tableting parameters. These results suggest that TRS is a versatile non-destructive quantitative analysis method that can be applied in tablet manufacturing.

Novel Bioequivalent Tablet of Solifenacin Succinate Prepared Using Direct Compression Technique for Improved Chemical Stability

We designed a bioequivalent tablet form of solifenacin succinate (SOL) with an improved storage stability using a direct compression (DC) technique. An optimal direct compressed tablet (DCT) containing an active substance (10 mg), lactose monohydrate, and silicified microcrystalline cellulose as diluents, crospovidone as a disintegrant, and hydrophilic fumed silica as an anti-coning agent was constructed by evaluating the drug content uniformity, mechanical properties, and in vitro dissolution. The physicochemical and mechanical properties of the DCT were as follows: drug content 100.1 ± 0.7%, disintegration time of 6.7 min, over 95% release within 30 min in dissolution media (pH 1.2, 4.0, 6.8, and distilled water), hardness > 107.8 N, and friability ~0.11%. The SOL-loaded tablet fabricated via DC showed an improved stability at 40 °C and RH 75%, exhibiting markedly reduced degradation products compared to those fabricated using ethanol or water-based wet granulation or a marketed product (Vesicare^®, Astellas Pharma). Moreover, in a bioequivalence study in healthy subjects (n = 24), the optimized DCT offered a pharmacokinetic profile comparable to that of the marketed product, with no statistical differences in the pharmacokinetic parameters. The 90% CIs for the geometric mean ratios of the test to the reference formulation for the area under the curve and the maximum drug concentration in plasma were 0.98-1.05 and 0.98-1.07, respectively, and satisfied the FDA regulatory criteria for bioequivalence. Thus, we conclude that DCT is a beneficial oral dosage form of SOL with an improved chemical stability.

[Advances in Pharmaceutical Manufacturing Process Management -From Physical Pharmaceutics to Automatic Pharmaceutical Production]

Since entering graduate school 43 years ago, I have been studying physical pharmaceutics with a focus on the effects of environmental factors on pharmaceutical properties of solid oral dosage forms during the manufacturing process. I have reported on changes in the characteristics of pharmaceutical products during manufacturing processes, such as grinding, mixing, granulation, and tableting owing to complicated phenomena based on chemical reactions or the crystalline polymorphic transitions of bulk drugs and excipients. To develop modern pharmaceutical manufacturing processes based on process analysis technology (PAT) as a next generation good manufacturing practice, real-time monitoring was introduced in these processes using a non-destructive analytical method, such as the near-infrared spectroscopy combined with chemometrics. Many case studies related to the mixing, granulation, tableting, and coating processes involving PAT have been reported. In those studies, I focused on clarifying the physical and chemical mechanism through "design space" representation. Additionally, non-destructive analytical methods, including X-ray computed tomography, audible acoustic emission, Raman spectroscopy, terahertz spectroscopy, and infrared thermal imaging analysis were applied as novel candidate analytical methods to the pharmaceutical process to monitor critical quality attributes. To achieve this purpose in various pharmaceutical dosage forms, I have been attempting the assembly of a modern manufacturing process managed through a "design space" paradigm involving in-line monitoring using novel analytical methods, multivariate analyses, and feed-back systems.

Injection-Molded Coamorphous Tablets: Analysis of Intermolecular Interaction and Crystallization Propensity

The processing steps involved in converting from a powder to a tablet entail numerous operations in a which the coamorphous system is recrystallized and dissociated easily. This research focused on (i) a single-step preparation of a coamorphous tablet during injection molding (IM) from the bulk powder, and (ii) a mechanistic characterization of the coamorphous formulation. We selected several organic acids [citric acid, succinic acid, tartaric acid, and malic acid] in an effort to compound with basic loratadine (a poorly water-soluble drug). Loratadine-acids coamorphous tablets were produced via an IM process, and the dissolution was more enhanced than in the pure loratadine amorphous. The interaction was analyzed by FT-IR and terahertz spectroscopies. Each tablet was stored at 40 °C/75%RH, and then XRD patterns were acquired at the desired timepoints. In summary, loratadine exhibited ionic interaction with each acid, and the physical stability of the coamorphous tablet was in proportion to the loratadine-acids interaction strength. Terahertz spectra detected the molecular mobility, which plays an important role in the crystallization propensity of a coamorphous system. This understanding offers a framework for robust coamorphous tablet formulation using the IM methodology.