Effect of drug substance particle size on the characteristics of granulation manufactured in a high-shear mixer

Effect of Rotating Cylinder on Mixing Performance in a Cylindrical Double-Ribbon Mixer

Uniform mixing is highly essential in the food manufacturing, pharmaceutical, chemical, and cement industries. However, based on the various process requirements, these industries use different mixers to achieve their commercial outputs. Most of these industries rely on sample-based verification of the mixing index, which may not produce accurate results. Adopting a non-sampling mixing index method is more accurate. In this study, we used the discrete element method (DEM) to simulate the mixing of multiple components contained in a typical commercial whey protein mixture. An effective non-sampling mixing index, the subdomain-based mixing index (SMI), was incorporated to assess the mixing levels. The main motivation for this study was to acquire a high mixing index in the least possible mixing time to boost the manufacturing rate. For this purpose, a half-filled cylindrical double ribbon mixer was simulated, and the SMI outputs are presented for the following four cases: (1) rotating ribbon, (2) rotating cylinder, (3) rotating cylinder with a static ribbon, and (4) rotating cylinder and ribbon. For the given simulation conditions, the SMI values ranged from 0 (segregation condition) to 0.91–0.94 (fully randomly mixed condition) within a time range of 0–60 s.

Twin Screw Granulation: Effects of Properties of Primary Powders

Lactose and mannitol are some of the most commonly used powders in the pharmaceutical industry. The limited research published so far highlights the effects of process and formulation parameters on the properties of the granules and the tablets produced using these two types of powders separately. However, the comparison of the performance of these two types of powders during twin screw wet granulation has received no attention. The present research is focused on understanding the granulation mechanism of different grades of two pharmaceutical powders with varying properties (i.e., primary particle size, structure, and compressibility). Three grades each of lactose and mannitol were granulated at varying liquid to solid ratios (L/S) and screw speed. It was noticed that primary powder morphology plays an important role in determining the granule size and structure, and tablet tensile strength. It was indicated that the processed powders such as spray-dried and granulated lactose and mannitol can be used in formulation for wet granulation where flowability of active pharmaceutical ingredient (API) is poor.

A quality by design approach to scale-up of high-shear wet granulation process

High-shear wet granulation is a complex process that in turn makes scale-up a challenging task. Scale-up of high-shear wet granulation process has been studied extensively in the past with various different methodologies being proposed in the literature. This review article discusses existing scale-up principles and categorizes the various approaches into two main scale-up strategies - parameter-based and attribute-based. With the advent of quality by design (QbD) principle in drug product development process, an increased emphasis toward the latter approach may be needed to ensure product robustness. In practice, a combination of both scale-up strategies is often utilized. In a QbD paradigm, there is also a need for an increased fundamental and mechanistic understanding of the process. This can be achieved either by increased experimentation that comes at higher costs, or by using modeling techniques, that are also discussed as part of this review.

Impact of micromeritic properties of an active pharmaceutical ingredient on its compaction behavior

Physical characteristics of an active pharmaceutical ingredient (API) can have a significant impact on the processability of a high drug loading formulation. This paper provides an example where different micromeritic properties of an API were obtained by crystallization under different conditions, resulting in different tableting behavior. While the API form purity was maintained during the crystallization process change, significant changes were incurred in the surface geometry, porosity and surface area of the API. The batches consisting of particles with greater surface irregularity and porosity gave tablets of higher mechanical strength.

Initial moisture content in raw material can profoundly influence high shear wet granulation process

The aim of this work is to demonstrate that uncontrolled initial moisture content in microcrystalline cellulose (MCC) can profoundly affect high shear wet granulation (HSWG) process. We show that granule tabletability is reduced by approximately 50% when initial moisture content in MCC increases from 0.9% to 10.5% while all other processing parameters remain unchanged. An important observation is that granule tableting performance deteriorates significantly when initial moisture content increases from 2.6% to 4.9%, which is considered normal variation in moisture content for typical MCC (3-5%). The deteriorated tabletability is largely caused by increased granule size. On the other hand, granule flowability improves continuously with increasing initial moisture content in MCC. The improved flowability is mainly a result of granule size enlargement. Clearly, moisture content of raw materials for a HSWG process must be carefully monitored and controlled to ensure a robust manufacturing process as required by the quality-by-design principle.

Multiphase versus Single Pot Granulation Process: Influence of Process and Granulation Parameters on Granules Properties

High-shear wet granulation is widely used for the production of pharmaceutical dosage forms. Different equipment is available for high-shear granulation and drying. This review focuses on two main processes for granules production: multiphase consisting of high-shear granulation followed by drying in a separate apparatus, and single pot granulation/drying. At present, formulas are specifically developed with regard to the production equipment, which raises many problems when different industrial manufacturing equipment is used. Indeed, final granules properties are likely to depend on equipment design, process, and formulation parameters. Therefore, a good understanding of these parameters is essential to facilitate equipment changes. The aim of this review is to present the influence of equipment, process, and formulation parameters on granules properties, considering both the granulation and the drying steps of multiphase and single pot processes.

Effect of starting material particle size on its agglomeration behavior in high shear wet granulation

The effect of anhydrous lactose particle size distribution on its performance in the wet granulation process was evaluated. Three grades of anhydrous lactose were used in the study: "as is" manufacturer grade and 2 particle size fractions obtained by screening of the 60M lactose. Particle growth behavior of the 3 lactose grades was evaluated in a high shear mixer. Compactibility and porosity of the resulting granules were also evaluated. A uniaxial compression test on moist agglomerates of the 3 lactose grades was performed in an attempt to explain the mechanism of particle size effect observed in the high shear mixer. Particle growth of anhydrous lactose in the high shear mixer was inversely related to the particle size of the starting material. In addition, granulation manufactured using the grade with the smallest particle size was more porous and demonstrated enhanced compactibility compared with the other grades. Compacts with similar porosity and low liquid saturation demonstrated brittle behavior and their breakage strength was inversely related to lactose particle size in the uniaxial compression test, suggesting that material with smaller particle size may exhibit more pronounced nucleation behavior during wet granulation. On the other hand, compacts prepared at higher liquid saturation and similar compression force exhibited more plastic behavior and showed lower yield stress for the grade with smallest particle size. The lower yield stress of compacts prepared with this grade may indicate a higher coalescence tendency for its granules during wet granulation.