The challenge of downstream processing of spray dried amorphous solid dispersions into minitablets designed for the paediatric population - A sustainable product development approach

Poorly water-soluble drugs present a significant challenge in the development of oral solid dosage forms (OSDs). In formulation development the appropriate use of excipients to adjust solubility, and the choice of manufacturing method and pharmaceutical processes to obtain a dosage form to meet the needs of the patient group, is crucial. Preparing an amorphous solid dispersion (ASD) is a well-established method for solubility enhancement, and spray drying (SD) a common manufacturing method. However, the poor flowability of spray dried materials poses a significant challenge for downstream processing. Promoting sustainability in OSD development involves embracing a versatile formulation design, which enables a broader spectrum of patients to use the product, as opposed to altering existing dosage forms retrospectively. The objective of the current study was to develop a formulation of spray dried indomethacin ASD suited to the production, by direct compression, of instant release paediatric minitablets. Excipients evaluated were PVP or HPMCAS in solid dispersions at the preformulation phase, and MCC and lactose as a filler in direct compression. From the studied formulations, a 3:1 ratio blend of Vivapur 200/Pharmatose 200 M (MCC/lactose) with 0.5% (w/w) magnesium stearate was found to be the most promising in tableting, and minitablets containing a 6.22% content of spray-dried ASD of indomethacin/PVP K 29-32 could be obtained with desired tablet hardness and pharmaceutical quality, complying with tests of weight variation and fast disintegration in an aqueous environment. As a case example, this study provides a good foundation for further studies in harnessing a sustainable approach to the development of pharmaceutical formulations that can appropriately serve different patient sub-populations.

Study of compaction tools and parameters on critical quality attributes of high drug load minitablets

Minitablets are prepared using multiple die openings and multi-tip punches for greater productivity. With multiple tips on the punch barrel, the overall compaction force to be applied is commonly estimated by multiplying the desired compaction force per tip by the number of punch tips. Few researchers have however examined this proportionality and the effects of the number of punch tips and punch face geometry on the critical quality attributes (CQAs) of high drug load minitablets. In this study, the minitablets prepared by multi-tip tools exhibited greater weight variation than those prepared by single-tip tools. Their compaction was accompanied by a longer dwell time that led to a higher minitablet tensile strength and consequently a longer disintegration time. The compaction forces required to achieve a consistent set of minitablet CQAs were not directly proportional to the number of punch tips used. In comparison, the effect of punch face geometry was negligible. Increasing concentration of magnesium stearate (as lubricant) from 0.75 to 1.25 %, w/w reduced weight variation, especially of minitablets prepared by the multi-tip tools. It also increased the disintegration time but had no significant effect on the tensile strength of the minitablets regardless of type of tools used. The adjustment of compaction speed was an effective compensatory method to mitigate the differences in dwell time and tensile strength between minitablets prepared by single-tip and multi-tip standard concave tools. A larger reduction in compaction speed of the single-tip tools was required at higher compaction pressures.

Microparticles and multi-unit systems for advanced drug delivery

Microparticles have unique benefits in the formulation of multiparticulate and multi-unit type pharmaceutical dosage forms allowing improved drug safety and efficacy with favorable pharmacokinetics and patient centricity. On the other hand, the above advantages are served by high and well reproducible quality attributes of the medicinal product where even flexible design and controlled processability offer success as well as possible longer product life-cycle for the manufacturers. Moreover, the specific demands of patients can be taken into account, including simplified dosing regimens, flexible dosage, drug combinations, palatability, and ease of swallowing. In the more than 70 years since the first modified-release formulation appeared on the market, many new formulations have been marketed and many publications have appeared in the literature. More unique and newer pharmaceutical technologies and excipients have become available for producing tailor-made particles with micrometer dimensions and beyond. All these have contributed to the fact that the sub-units (e.g. minitablets, pellets, microspheres) that make up a multiparticulate system can vary widely in composition and properties. Some units have mucoadhesive properties and others can float to contribute to a suitable release profile that can be designed for the multiparticulate formula as a whole. Nowadays, there are some available formulations on the market, which are able to release the active substance even for several months (3 or 6 months depending on the type of treatment). In this review, the latest developments in technologies that have been used for a long time are presented, as well as innovative solutions such as the applicability of 3D printing to produce subunits of multiparticulate systems. Furthermore, the diversity of multiparticulate systems, different routes of administration are also presented, touching the ones which are capable of carrying the active substance as well as the relevant, commercially available multiparticle-based medical devices. The versatility in size from 1 µm and multiplicity of formulation technologies promise a solid foundation for the future applications of dosage form design and development.

Impact of Lubrication on Key Properties of Orodispersible Minitablets in Comparison to Conventionally Sized Orodispersible Tablets

Orodispersible minitablets (ODMTs) offer several benefits like easy swallowability, dose flexibility and simple manufacturing through direct compression. In this study, the effect of lubrication on five different co-processed excipients (Ludiflash®, Parteck® ODT, Prosolv® ODT G2, galenIQ™ 721 and SuperTab® 50 ODT) has been studied for orodispersible tablets (ODTs) with 11.28 and 2 mm in diameter. External lubrication was compared with internal lubrication using 0.5 %, 1 % or 2 % magnesium stearate or 1 %, 2 % or 4 % sodium stearyl fumarate. Mechanical strength and disintegration time of the ODTs were evaluated beside the lubrication efficiency. Especially mannitol-based co-processed excipients show strong dependency of the lubricant concentration whereas both ODTs and ODMTs and minitablets with isomalt showed comparable properties for both lubricants and their concentrations. Sodium stearyl fumarate is considered as the preferred lubricant for ODMTs as it showed a higher lubrication efficiency and less negative impact on disintegration time. External lubrication exhibited higher tensile strength for plastic materials, but increased the disintegration time, particularly for ODMTs due to the high specific surface where the lubricant is applied. In general, this study has demonstrated that minitablets require higher lubricant concentrations than conventionally sized tablets.

Charge Reduction Assisted Production of Diminutive Fluid Bed Granules for High Drug Load Minitablets

Micronized drug powders are generally unsuitable as tableting feed to produce minitablets due to their cohesivity and poor flow. The silicification of fine paracetamol powder (PCM_F) with an optimal concentration range of fumed silica (fSi) [0.7 - 0.9 %, w/w] reduced the net negative charge of PCM_F and improved powder flow. The optimal fSi concentration range suitable was established through the measurement of charge and flowability of the silicified powders. Silicification of PCM_F by physical mix did not satisfactorily overcome the cohesive forces between the PCM_F crystals and improve powder flow sufficiently such that it will feed consistently into the smaller die orifices during tableting. Using a specialized fluid bed system with swirling air and side spray, controlled granulation of silicified PCM_F packed and agglomerated the interlocking-prone needle shaped PCM_F crystals into diminutive granules that are more spherical and free flowing. With optimized fSi concentration (≈ 0.8 %, w/w) and granulation process parameters, high drug load diminutive granules (D₅₀≃ 90 μm) were successfully prepared from PCM_F as starter seeds (D₅₀≃ 30 μm). Minitablets prepared from the diminutive granules had low weight variation, and were mechanically strong with disintegration time of less than 30 s. This study demonstrated the feasibility of producing high drug load minitablets from a cohesive, electrostatic-prone fine drug powder.

Dispensing of minitablets - Has the problem been resolved?

Recently, minitablets have been given extensive coverage in literature, as they are perfectly matched to the current therapy individualization trend. Within this scope, special attention is paid to minitablets that enable convenient drug intake for patients with swallowing problem. However, the packaging system, dispensing the necessary amount of drug units and safe administration still remain unsolved problems or are partially overlooked. Although there are many different approaches towards dosing tablets, only a few seem to be tailored to particularly small tablets. Moreover, none of these approaches meets all the user's expectations. This paper comprehensively elaborates and critically discusses the available dosing options like sachets, blisters, home electronic dispensing systems and minitablets manual dispensers. Additional tests have been also conducted to simulate the handling and dosing procedure with 2 mm diameter placebo minitablets. Despite many advantageous inventions, it has been revealed that further efforts are necessary to identify the optimal design that would allow to eliminate the shaking procedure, adjust cavities diameter or provide better protection against humidity. Nevertheless, the current trend may lead to individual therapy becoming more convenient, safe and reliable, especially in pediatric and geriatric patients.

The Development of Minitablets for a Pediatric Dosage Form for a Combination Therapy

Minitablets are an appealing option for an age-appropriate pediatric dosage form. In particular, for combination therapies where multiple active ingredients are dosed simultaneously, the use of minitablets will enable independent adjustments of each dose. The work presented describes the development of Compound A and Compound B minitablets for a combination therapy. Since both actives are formulated as spray dried amorphous solid dispersions (ASDs) due to low solubility of their crystalline forms, the choice of minitablets for the pediatric dosage form allows the application of the same formulation strategy across different age groups. To address the potential need for taste-masking, an ethylcellulose-hydroxypropyl cellulose coating system was developed. In-vitro performance testing was conducted to guide coating development and to ensure proper taste-masking without slowing down API dissolution in the GI tract that can negatively impact exposures. As a result, the exposure of orally dosed coated tablets was comparable to those of uncoated minitablets in the canine model. The work presented can serve as a case study on how minitablets can be designed and developed as an appropriate pediatric dosage form for a combination therapy comprised of ASD of active ingredients.

Acceptability of Multiple Uncoated Minitablets in Infants and Toddlers: A Randomized Controlled Trial

OBJECTIVES

To assess the acceptability and swallowability of several minitablets when administered as a unit dose compared with an equivalent dose of syrup in children aged 6 months to 5 years.

STUDY DESIGN

The acceptability and swallowability of multiple drug-free minitablets in comparison with glucose syrup was assessed in 372 children of 2 age groups (186 in age group 1 [6-23 months of age] and 186 in age group 2 [2-5 years of age]) in a randomized, 3-way, single administration cross-over study. Age group 1 received 25 minitablets, 100 minitablets, and 5 mL syrup. Age group 2 received 100 minitablets, 400 minitablets, and 10 mL syrup.

RESULTS

Superiority was demonstrated in age group 1 for acceptability (25 minitablets, P < .017; 100 minitablets, P < .0001) and swallowability (25 minitablets and 100 minitablets, both P < .0001) compared with syrup. In age group 2, noninferiority of acceptability was found only for 400 minitablets (P < .0003), not for 100 minitablets. Subgroup analysis revealed a strong sequential effect. For swallowability, noninferiority could be demonstrated for 100 minitablets (P < .01) but not for 400 minitablets.

CONCLUSIONS

Administration of ≥25 minitablets is well-tolerated, feasible, and safe in children aged from 6 months, and was superior to the equivalent dose of syrup. Children aged >1 year accept ≤400 minitablets even better than the equivalent dose of syrup. Minitablets open the perspective for introducing small-sized solid drug formulations for all children, thus, further shifting the paradigm from liquid toward small-sized solid drug formulations.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS): DRKS00008843.

Determination of coating thickness of minitablets and pellets by dynamic image analysis

The study was focused on the feasibility of measuring film thickness on minitablets and pellets by means of dynamic image analysis using Camsizer XT. Minitablets with diameters of 2.0mm or 2.5mm and pellets in the size range of 0.7-0.8mm with the polymer coating thickness of 80-170 μm were prepared and analyzed. In minitablets the film thickness was measured on the walls and edges and the difference was significant. The results were compared with the results obtained with the use of three microscopic methods (scanning and stereoscopic microscopy). Good correlation between dynamic image analysis and microscopic techniques was shown in the case of the film thickness in pellets and 2.0mm minitablets, but the measurement of the coating layer of larger particles (minitablets 2.5mm) was not sufficiently precise due to the non-isometric shape of these objects and the limited measuring range of the apparatus. Short analysis time, no need for sample preparation and a large number of objects under examination are main advantages of the proposed film thickness measurement by use of a dynamic image analysis.