Co-Processed Particles: An Approach to Transform Poor Tableting Properties

Investigating the Impact of Co-processed Excipients on the Formulation of Bromhexine Hydrochloride Orally Disintegrating Tablets (ODTs)

PURPOSE

Orodispersible tablets (orally disintegrating tablets, ODTs) have been used in pharmacotherapy for over 20 years since they overcome the problems with swallowing solid dosage forms. The successful formula manufactured by direct compression shall ensure acceptable mechanical strength and short disintegration time. Our research aimed to develop ODTs containing bromhexine hydrochloride suitable for registration in accordance with EMA requirements.

METHODS

We examined the performance of five multifunctional co-processed excipients, i.e., F-Melt® C, F-Melt® M, Ludiflash®, Pharmaburst® 500 and Prosolv® ODT G2 as well as self-prepared physical blend of directly compressible excipients. We tested powder flow, true density, compaction characteristics and tableting speed sensitivity.

RESULTS

The manufacturability studies confirmed that all the co-processed excipients are very effective as the ODT formula constituents. We noticed superior properties of both F-Melt's®, expressed by good mechanical strength of tablets and short disintegration time. Ludiflash® showed excellent performance due to low works of plastic deformation, elastic recovery and ejection. However, the tablets released less than 30% of the drug. Also, the self-prepared blend of excipients was found sufficient for ODT application and successfully transferred to production scale. Outcome of the scale-up trial revealed that the tablets complied with compendial requirements for orodispersible tablets.

CONCLUSIONS

We proved that the active ingredient cannot be absorbed in oral cavity and its dissolution profiles in media representing upper part of gastrointestinal tract are similar to marketed immediate release drug product. In our opinion, the developed formula is suitable for registration within the well-established use procedure without necessity of bioequivalence testing.

Surface Modifiers on Composite Particles for Direct Compaction

Direct compaction (DC) is considered to be the most effective method of tablet production. However, only a small number of the active pharmaceutical ingredients (APIs) can be successfully manufactured into tablets using DC since most APIs lack adequate functional properties to meet DC requirements. The use of suitable modifiers and appropriate co-processing technologies can provide a promising approach for the preparation of composite particles with high functional properties. The purpose of this review is to provide an overview and classification of different modifiers and their multiple combinations that may improve API tableting properties or prepare composite excipients with appropriate co-processed technology, as well as discuss the corresponding modification mechanism. Moreover, it provides solutions for selecting appropriate modifiers and co-processing technologies to prepare composite particles with improved properties.

Study of Orally Disintegrating Tablets Using Erythritol as an Excipient Produced by Moisture-Activated Dry Granulation (MADG)

Moisture-activated dry granulation (MADG) is an eco-friendly granulation method that uses a small amount of water and insoluble excipients to absorb moisture. MADG is expected to improve productivity and reduce costs. Erythritol, an excipient used for preparing orally disintegrating tablets (ODTs), has poor tabletability and is difficult to form into tablets by conventional methods, such as high-shear granulation (HSG) and direct compression. In this study, we optimized the manufacturing conditions for ODTs to improve the tabletability of erythritol using MADG. The disintegration time of tablets made using the MADG method was approximately one-tenth that of those made using the HSG method, and the hardness was approximately 1.4 times higher. Moreover, MADG could delay disintegration and improve tabletability. We further attempted to optimize the manufacturing conditions using MADG, particularly in terms of the amount of water used. The disintegration time increased as the amount of added water increased. Moreover, water absorption tests revealed that capillary wetting decreased as the amount of water added increased, but the initial wetting did not change. These results suggested that the disintegration time was prolonged because of the increase in granule density and decrease in capillary wetting with the increase in the amount of added water. The hardness of the tablets increased because of the easy deformation of the granules after the addition of up to 3% water; however, when more than 3% water was added, the hardness decreased because of the aggregation of the granules with the excess water. Finally, two-dimensional maps of the effect of the amount of added water and water activity indicated that tablets with a hardness of ≥80 N and a disintegration time of ≤15 s could be produced by adjusting the amount of added water to within the range of 2.2–3.3% and water activity to 0.3–0.53. These results indicate that MADG can improve the tabletability of erythritol and be used for the granulation of ODTs. Tablets with appropriate hardness and disintegration properties can be produced by adjusting the water content to approximately 2.7% and the water activity to approximately 0.4 when producing ODTs with MADG.

Application of Machine-Learning Algorithms for Better Understanding of Tableting Properties of Lactose Co-Processed with Lipid Excipients

Co-processing (CP) provides superior properties to excipients and has become a reliable option to facilitated formulation and manufacturing of variety of solid dosage forms. Development of directly compressible formulations with high doses of poorly flowing/compressible active pharmaceutical ingredients, such as paracetamol, remains a great challenge for the pharmaceutical industry due to the lack of understanding of the interplay between the formulation properties, process of compaction, and stages of tablets’ detachment and ejection. The aim of this study was to analyze the influence of the compression load, excipients’ co-processing and the addition of paracetamol on the obtained tablets’ tensile strength and the specific parameters of the tableting process, such as (net) compression work, elastic recovery, detachment, and ejection work, as well as the ejection force. Two types of neural networks were used to analyze the data: classification (Kohonen network) and regression networks (multilayer perceptron and radial basis function), to build prediction models and identify the variables that are predominantly affecting the tableting process and the obtained tablets’ tensile strength. It has been demonstrated that sophisticated data-mining methods are necessary to interpret complex phenomena regarding the effect of co-processing on tableting properties of directly compressible excipients.

Understanding Deformation Behavior and Compression Speed Effect in Gabapentin Compacts

Deformation mechanism and strain rate sensitivity of gabapentin powder was investigated in this work. Heckel analysis, specific surface area and indentation hardness measurements revealed an intermediate yield pressure and brittle fracture as the dominant type of deformation mechanism during consolidation. Strain rate sensitivity of gabapentin was studied by compressing it at 1 mm/min and 500 mm/min compression speeds. Gabapentin demonstrated an atypical strain rate sensitivity in compactibility profile (tensile strength vs. solid fraction). Compacts of gabapentin compressed at fast speed showed an increase in tensile strength when compared with those compressed at slow speed. To understand the effect of compression speed on gabapentin's compactibility, PXRD analysis, surface area analysis, indentation hardness measurements, and consolidation modeling were performed. PXRD analysis carried out on compacts revealed no effect of speed on the physical solid-state stability of gabapentin. Specific surface area of compacts made at fast speed was higher than that of compacts made at slow speed. Indentation measurements performed on gabapentin compacts showed higher values of hardness in the case compacts made at fast speed. It was identified that at the fast compression speed, gabapentin shows greater particle fragmentation and form compacts with smaller pores.

Profound tabletability deterioration of microcrystalline cellulose by magnesium stearate

Magnesium stearate (MgSt) is a common lubricant used in tablet formulations to facilitate tablet manufacturing by reducing ejection force. The use of MgSt in tablet formulation is known to potentially deteriorate tabletability of plastic powders and slow down drug dissolution. Here, we report surprisingly profound deterioration in tabletability of microcrystalline cellulose by hand-mixing. We also show that the hand mixing process is highly variable. To ensure the reproducibility of tabletability assessment of powders, hand-mixing should be used with caution. For research that employs hand mixing, mixing procedure should be carefully controlled and reported.

Effect of Different Direct Compaction Grades of Mannitol on the Storage Stability of Tablet Properties Investigated Using a Kohonen Self-Organizing Map and Elastic Net Regression Model

This study tested 15 direct compaction grades to identify the contribution of different grades of mannitol to the storage stability of the resulting tablets. After preparing the model tablets with different values of hardness, they were stored at 25 °C, 75% relative humidity for 1 week. Then, measurement of the tablet properties was conducted on both pre- and post-storage tablets. The tablet properties were tensile strength (TS), friability, and disintegration time (DT). The experimental data were analyzed using a Kohonen self-organizing map (SOM). The SOM analysis successfully classified the test grades into three distinct clusters having different changes in the behavior of the tablet properties accompanying storage. Cluster 1 showed an obvious rise in DT induced by storage, while cluster 3 showed a substantial change in mechanical strength of the tablet including a reduction in the TS and a rise in friability. Furthermore, the data were analyzed using an Elastic net regression technique to investigate the general relationships between the powder properties of mannitol and the change behavior of the tablet properties. Consequently, we succeeded in identifying the crucial powder properties for the storage stability of the resulting tablets. This study provides advanced technical knowledge to characterize the effect of different direct compaction grades of mannitol on the storage stability of tablet properties.

Characterization of Powder- and Tablet Properties of Different Direct Compaction Grades of Mannitol Using a Kohonen Self-organizing Map and a Lasso Regression Model

The purpose of this study was to accumulate enhanced technical knowledge about the powder properties of direct compaction grades of mannitol that could lead to new tablet formulations. Fifteen different commercial direct compaction grades of mannitol were tested. Ten different powder properties representing flowability, particle size, specific surface area and manufacturing properties were measured. In addition, model tablets of each mannitol grade were prepared, and their disintegration time, friability, and tensile strength were measured. The data were analyzed by principle component analysis and a Kohonen self-organizing map to find correlations between powder properties. Self-organizing map clustering successfully classified the test grades into 5 distinct clusters having different powder properties. Each cluster was well characterized by statistical profiling. Subsequently, the contribution of the powder properties to the tablet properties was investigated by a least absolute shrinkage- and selection operator (Lasso) regression model. Mannitol grades with a larger particle size (D90) were prone to produce tablets with longer disintegration time, while a larger specific surface area of the particles was positively associated with tablets with higher mechanical strength. Our findings provide valuable information for the design of tablet formulations.