Glidants are important excipients in drug tablet production. They prevent sticking of the tablet components to the punches of the tablet press leading to its halt. Mg stearate, a classical hydrophobic glidant, has many negative properties, such as reduced tablet hardness, prolonged tablet disintegration and slowing down the drug release. It is also incompatible with strongly acid or alkaline drugs. A newer glidant Na stearyl fumarate and a new glidant Syloid (micronized synthetic amorphous silica gel) show better properties. The influence of the glidants on the parameters of the compaction equation at the stages of precompression and elastic and plastic deformation are stu¬died. The effect of glidants on tablet hardness is evaluated as well. Syloid decreases the tablet hardness only very little and provides a higher rate of volume reduction in the compaction process.
In recent years, CM has become increasingly popular in the pharmaceutical industry for the production of OSD forms. Most of the newly developed APIs nowadays are extremely cohesive and sticky with a mean particle size particle of <100 μm, a wide PSD and a high tendency to agglomerate, making them difficult to accurately dose using loss-in-weight equipment during CM. In this research paper, the effect of various glidants on the volumetric and gravimetric feeding of several APIs was assessed. Three challenging API (APAPμ, MPT and SD) and four different glidants (Aerosil® 200, Aerosil® R972, Syloid® 244FP and TRI-CAFOS® 200-7) were selected. For all feeding trials, a GEA CF equipped with 20 mm concave screws was used, in combination with an external catch scale. The volumetric feeding trials showed the ability of each glidant to increase the FFmax and reduce the FFmovRSD40 and the FFdecay for the cohesive APIs (APAPμ and MPT). Although the fumed silica grades showed the highest impact on the previously mentioned feeding parameters, low AE10 values were obtained, negatively affecting the feeding performance at higher glidant concentration. Both Syloid 244FP and TCP were good alternatives. However, to obtain a similar feeding performance a higher concentration of these glidants is required. The volumetric trials showed that glidant addition has no additional benefits for APIs with good flow properties such as SD. The second part of this paper discussed the impact of glidant addition on the gravimetric feeding behavior of the cohesive powders. Both the fumed silica grades (Aerosil® 200 and Aerosil® R972) and Syloid 244FP lowered the deviation on all LC% profiles of the cohesive APIs. In contrast to the volumetric trails, blends with excess fumed silica resulted in low AE10 values which are efficiently dosed by the CF during the gravimetric feeding.
- MeSH
- Chemistry, Pharmaceutical methods MeSH
- Technology, Pharmaceutical methods MeSH
- Pharmaceutical Preparations chemistry administration & dosage MeSH
- Bulk Drugs MeSH
- Silicon Dioxide chemistry MeSH
- Excipients * chemistry MeSH
- Drug Compounding methods MeSH
- Particle Size * MeSH
- Publication type
- Journal Article MeSH
The work was aimed at evaluating the efficiency of multifunctional magnesium aluminosilicate materials (MAS) as a novel glidant in solid dosage forms. MAS are known for their very low cohesive interactions and their utilization could avoid the disadvantages associated with conventional glidant usage. Flow properties of several mixtures comprising a model excipient (microcrystalline cellulose) and a glidant were characterized using a powder rheometer FT4. The mixtures were formulated to represent effects of glidant types, various levels of glidant loading, particle size and mixing time on flow properties of the model excipient. Pre-conditioning, shear testing, compressibility, flow energy measurements and an additional tapping test were carried out to monitor flow properties. Mixtures were analyzed employing scanning electron microscopy, using a detector of back-scattered electrons to identify a mechanism of MAS towards improving the mixture flow properties. All studied parameters were found to have substantial effects on mixture flow properties, but the effect of mixing time was much less important compared to mixtures based on traditional glidant. The mechanism of MAS glidant action was found to be different compared to that of traditional one, having less process sensitivity, so that MAS utilization as glidant could be advantageous for the formulation performance.
- MeSH
- Excipients * MeSH
- Powders MeSH
- Rheology MeSH
- Silicates * MeSH
- Aluminum Compounds MeSH
- Magnesium Compounds MeSH
- Particle Size MeSH
- Publication type
- Journal Article MeSH
Nowadays, most of the newly developed active pharmaceutical ingredients (APIs) consist of cohesive particles with a mean particle size of <100μm, a wide particle size distribution (PSD) and a tendency to agglomerate, therefore they are difficult to handle in continuous manufacturing (CM) lines. The current paper focuses on the impact of various glidants on the bulk properties of difficult-to-handle APIs. Three challenging powders were included: two extremely cohesive APIs (acetaminophen micronized (APAPμ) and metoprolol tartrate (MPT)) which previously have shown processing issues during different stages of the continuous direct compression (CDC)-line and a spray dried placebo (SD) powder containing hydroxypropylmethyl cellulose (HPMC), known for its sub-optimal flow with a high specific surface area (SSA) and low density. Four flow-enhancing excipients were used: a hydrophilic (Aerosil® 200) and hydrophobic (Aerosil® R972) fumed silica grade, a mesoporous silica grade (Syloid® 244FP), and a calcium phosphate excipient (TRI-CAFOS® 200-7). The APIs and binary API/glidant blends (varied between 0.5-2.75 w/w%) were characterized for their bulk properties relevant for CDC. The results indicated that optimizing different bulk parameters (e.g., density, flow, compressibility..) of an API required varying weight percentages of the glidant (e.g., different surface area coverage (SAC)) depending on the APIs. Moreover, even at similar SAC, the impact of the glidant on the bulk characteristic of the APIs depended on the glidant type properties. While nano-sized silicon dioxide were effective for improving the flowability of a powder, other glidants (mesoporous silica and tricalcium phosphate (TCP)) showed also promise as alternatives. Additionally, an excess of glidant, referred to as oversilication, negatively impacted some bulk parameters, but other characteristics were unaffected. Finally, to determine the appropriate concentration of the different classes of glidants, SAC calculations, an understanding of the glidant's working mechanism, and knowledge about the API's characteristics (i.e., morphology, compressibility, flowability, aeration, density, and wall friction) are required. This study confirmed the necessity of including various material characterization techniques to assess the impact of glidants on the bulk characteristics of APIs.
- MeSH
- Hypromellose Derivatives * chemistry MeSH
- Chemistry, Pharmaceutical methods MeSH
- Calcium Phosphates * chemistry MeSH
- Hydrophobic and Hydrophilic Interactions MeSH
- Metoprolol * chemistry MeSH
- Bulk Drugs MeSH
- Silicon Dioxide chemistry MeSH
- Acetaminophen * chemistry MeSH
- Excipients * chemistry MeSH
- Powders * MeSH
- Drug Compounding methods MeSH
- Rheology * MeSH
- Particle Size * MeSH
- Publication type
- Journal Article MeSH
In pharmaceutical industry, the use of lubricants is mostly based on historical experiences or trial and error methods even these days. It may be demanding in terms of the material consumption and may result in sub-optimal drug composition. Powder rheology enables more accurate monitoring of the flow properties and because the measurements need only a small sample it is perfectly suitable for the rare or expensive substances. In this work, rheological properties of four common excipients (pregelatinized maize starch, microcrystalline cellulose, croscarmellose sodium and magnesium stearate) were studied by the FT4 Powder Rheometer, which was used for measuring the compressibility index by a piston and flow properties of the powders by a rotational shear cell. After an initial set of measurements, two excipients (pregelatinized maize starch and microcrystalline cellulose) were chosen and mixed, in varying amounts, with anhydrous colloidal silicon dioxide (Aerosil 200) used as a glidant. The bulk (conditioned and compressed densities, compressibility index), dynamic (basic flowability energy) and shear (friction coefficient, flow factor) properties were determined to find an optimum ratio of the glidant. Simultaneously, the particle size data were obtained using a low-angle laser light scattering (LALLS) system and scanning electron microscopy was performed in order to examine the relationship between the rheological properties and the inner structure of the materials. The optimum of flowability for the mixture composition was found, to correspond to empirical findings known from general literature. In addition the mechanism of colloidal silicone dioxide action to improve flowability was suggested and the hypothesis was confirmed by independent test. New findings represent a progress towards future application of determining the optimum concentration of glidant from the basic characteristics of the powder in the pharmaceutical research and development.
