A systematic investigation of external lubrication of mini-tablets on a rotary tablet press with focus on the tensile strength

External lubrication is an alternative to internal lubrication and its related detrimental effects on properties of tablets like tensile strength (TS). However, to date there are hardly any systematic investigations on external lubrication of mini-tablets on rotary tablet presses. Aim of this study was the systematic investigation of the impact of parameters tableting pressure, tableting speed, dosing rate and air pressure on the TS of mini-tablets. Both studies, the Central Composite Design (CCD) with SMCC 90 and the subsequently executed D-optimal design with SMCC 50, exhibited that tableting pressure had the highest positive effect on TS. Tableting speed and dosing rate in the CCD presumably did not seem to influence the TS, air pressure represented a positive coefficient. An additional temporal factor seemed to impact the results, deduced from the negative effect of the experimental order on TS in the CCD and from the negative correlation along the execution order in the residual plots. Additional long runs support findings of a non-linear decrease of TS over time. An interplay between dosing rate level and performance of the dust extraction collector is assumed, making more magnesium stearate available in the tablet press and potentially causing gradual contamination of the powder over time.

Mini-tablets current use and future opportunities - An APV course on manufacturing, packaging, characterization and use of minitablets

Recently, APV organized in collaboration with Fette Compacting GmbH a course on current use and future opportunities of mini-tablets. The course including a workshop was attended by 30 participants and focused on the manufacturing, packaging, characterization and medical use of mini-tablets. It took place at the Headquarter of Fette Compacting GmbH in Schwarzenbek. This article provides an overview on the topics presented and discussed during the course.

Challenges in the transfer and scale-up of mini-tableting: Case study with losartan potassium

Mini-tablets (MTs) with losartan potassium were developed to treat the rare disease Epidermolysis Bullosa. The focus was placed on transfer and scale-up of a direct compressible formulation from the compaction simulator STYL'One Evo (CS) to the rotary tablet press Korsch XM 12 (RP). Transfer of tabletability and compactibility profiles from CS to RP did not show good agreement, e.g. at a tableting pressure of 125 MPa mean tensile strengths (TS) of 4 MPa on CS and 1-1.5 MPa on RP were reached. These results highlight the impact of the feed frame on final product qualities depending on process and material factors. In the scale-up studies the critical quality attributes (CQAs) mass variation, content uniformity, TS and disintegration time were investigated. After an appropriate run-up time, most CQAs reached a plateau, after reaching a balance between influx, efflux and distribution of lubricant in the feed frame. TS values of 1-2 MPa, disintegration times of max. 50 s, mass variation of 0.9-2.2 % (CV) and acceptance values below 15.0 were reached depending on chosen process parameters.

Development of Low-Cost, Weight-Adjustable Clofazimine Mini-Tablets for Treatment of Tuberculosis in Pediatrics

Clofazimine (CFZ) is an important component of the World Health Organization's (WHO) recommended all-oral drug regimen for treatment of multi-drug resistant tuberculosis (MDR-TB). However, the lack of a dividable oral dosage form has limited the use of the drug in pediatric populations, who may require lowering of the dose to reduce the likelihood of adverse drug events. In this study, pediatric-friendly CFZ mini-tablets were prepared from micronized powder via direct compression. Rapid disintegration and maximized dissolution in GI fluids was achieved using an iterative formulation design process. Pharmacokinetic (PK) parameters of the optimized mini-tablets were obtained in Sprague-Dawley rats and compared against an oral suspension of micronized CFZ particles to examine the effect of processing and formulation on the oral absorption of the drug. Differences in maximum concentration and area under the curve between the two formulations were non-significant at the highest dosing level tested. Variability between rats prevented bioequivalence from being determined according to guidelines outlined by the Food and Drug Administration (FDA). These studies provide an important proof-of-concept for an alternative, low-cost formulation and processing approach for the oral delivery of CFZ in manner that is suitable for children as young as 6 months of age.

Evaluation of two novel co-processed excipients for direct compression of orodispersible tablets and mini-tablets

Pediatric, geriatric, and other patients who suffer from swallowing difficulties represent a special patient group, where an increased need in appropriate formulation development is required. To overcome these mostly swallowability linked issues, orodispersible tablets (ODTs) and orodispersible mini-tablets (ODMTs) can be seen as a suitable alternative to improve compliance. Orodispersible tablets are oral solid dosage forms which rapidly disintegrate after contact with saliva, leaving a liquid dispersion, which can be easily swallowed. To fulfil the required quality criteria and optimize the formulations regarding tensile strength and disintegration time, co-processed excipients (CPE) based on mannitol are frequently used in the manufacturing of orodispersible tablets. This study aimed to systematically compare two new CPEs, namely Granfiller-D® and Hisorad® and evaluate their potential in future OD(M)T formulations with already marketed products. The performance of the CPEs was examined in combination with three different APIs. Disintegration time, sufficient mechanical strength and content uniformity for low dosed formulation were chosen as main quality aspects. Conventionally sized tablets (9 mm) with 50% drug load of ibuprofen and paracetamol were produced with each CPE. Low dosed OD(M)Ts with a drug load of 4% enalapril maleate were manufactured to study content uniformity. Large differences were visible in the formulations containing ibuprofen and only Hisorad® allowed to compress ODT fulfilling the specifications of Ph.Eur. and FDA regarding disintegration times (180 s and 30 s, respectively). For the poorly binding model drug paracetamol, none of the studied excipients showed a satisfactory performance, with maximum tensile strengths < 1 MPa. To reach content uniformity in low dosed ODMTs, Ludiflash® seems to be the most preferable alternative, as the formulation showed the lowest acceptance values (AV) according to Ph.Eur. (<4) as well as the smallest coefficient of variation (CV) in API content (CV < 2%). In conclusion, the study revealed that none CPE is the ideal choice for all approaches, but different CPEs should be selected dependent on different challenges during formulation development of OD(M)Ts.

Transfer and scale-up of the manufacturing of orodispersible mini-tablets from a compaction simulator to an industrial rotary tablet press

Orodispersible mini-tablets (ODMTs) are a promising dosage form for the pediatric use showing increasing interest from pharmaceutical industry. However, a scale-up process for ODMTs from a compaction simulator to a rotary tablet press following FDA and EMA guidelines has not been performed and investigated yet. Isomalt (galenIQ™721) and Ludiflash® both excipients with proven suitability for the development of ODMTs have been investigated in transfer and scale-up from a compaction simulator to a rotary tablet press. ODMTs with isomalt and Ludiflash® were produced on the rotary tablet press monitoring the product temperature over time and assessing the properties of the residual powder in the feed shoe. Critical quality attributes like tensile strength, mass and disintegration time were evaluated. The transfer from compaction simulator to rotary tablet press succeeded as for both excipients similar disintegration times, tabletability and compactibility profiles were obtained. However, during scale-up, disintegration time significantly increases over time for both excipients. Monitoring of the product temperature revealed that with increasing batch size the product temperature increases as well having a significant impact on disintegration time. The properties of ODMTs produced with the residual powder are comparable in tabletability and disintegration time compared with ODMTs produced from fresh powder.

Pediatric formulation development - Challenges of today and strategies for tomorrow: Summary report from M-CERSI workshop 2019

A workshop on "Pediatric Formulation Development: Challenges of Today and Strategies for Tomorrow" was organized jointly by the University of Maryland's Center of Excellence in Regulatory Science and Innovation (M-CERSI), the U.S. Food and Drug Administration (FDA) and the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) Drug Product Pediatric Working Group (PWG). This multi-disciplinary, pediatric focused workshop was held over a two-day period (18-19 Jun 2019) and consisted of participants from industry, regulatory agencies, academia and other organizations from both US and Europe. The workshop consisted of sequential sessions on formulation, analytical, clinical, and regulatory and industry lessons learned and future landscape. Each session began with a series of short framing presentations, followed by facilitated breakout sessions and panel discussion. The formulation session was dedicated to three main topics pertaining to drug product acceptability, excipients in pediatrics and oral administration device considerations. The analytical session discussed key considerations for dosing vehicle selection and analytical strategies for testing of different dosage forms, specifically mini-tablets (multiparticulates). The clinical session highlighted the influence of pediatric pharmacokinetics prediction on formulation design, pediatric drug development strategies and clinical considerations to support pediatric formulation design. The regulatory and industry lessons learned and future landscape session explored the regional differences that exist in regulatory expectations, requirements for pediatric formulation development, and key patient-centric factors to consider when developing novel pediatric formulations. This session also discussed potential collaboration opportunities and tools for pediatric formulation development. This manuscript summarizes the key discussions and outcomes of all the sessions in the workshop with a broadened review and discussion of the topics that were covered.

3D printed spherical mini-tablets: Geometry versus composition effects in controlling dissolution from personalised solid dosage forms

Oral dosage forms are by far the most common prescription and over-the-counter pharmaceutical dosage forms used worldwide. However, many patients suffer from adverse effects caused by their use of "one-size fits all" mass produced commercially available solid dosage forms, whereby they do not receive dedicated medication or dosage adjusted to their specific needs. The development of 3D printing paves the way for personalised medicine. This work focuses on personalised therapies for hypertensive patients using nifedipine as the model drug. 3D printed full solid and channelled spherical mini-tablets with enhanced surface area (1.6-fold higher) were printed using modified PVA commercial filaments loaded by passive diffusion (PD), and Kollidon VA64 (KVA) and ethylcellulose (EC) based filaments prepared by hot-melt extrusion (HME). Drug loading ranged from 3.7% to 60% based on the employed technique, with a 13-fold higher drug loading achieved with the HME compared to PD. Composition was found to have a more significant impact on drug dissolution than geometry and surface area. Both KVA and EC-based formulations exhibited a biphasic zero-order drug-release profile. Physicochemical characterization revealed that nifedipine was in the amorphous form in the KVA-based end-products which led to a greater dissolution control over a 24 h period compared to the EC-based formulations that exhibited low levels of crystallinity by PXRD. The proposed 3D printed spherical mini-tablets provide a versatile technology for personalised solid dosage forms with high drug loading and dissolution control, easily adaptable to patient and disease needs.

Development of a Pediatric Mini-Tablet Formulation for Expedited Preclinical Studies

Multiple considerations are essential to address the main challenges of dose flexibility and patient adherence in pediatric drug development, particularly for oncology. Mini-tablets, 2 mm in diameter, were manufactured using a rotary tablet press at a set weight and compression force level. The physical characteristics were consistent for mini-tablets throughout multiple batches. Polymeric amorphous solid dispersion (ASD) was used as a solubility enhancing technique to increase solubility and exposure of lapatinib. The effects of the polymeric excipient and disintegrant on drug release properties were investigated. While having a lower apparent solubility and shorter storage stability, hydroxypropyl methylcellulose E3 (HPMCE3) formulation provided a higher percentage of drug release compared to hydroxypropyl methylcellulose phthalate (HPMCP). The intermolecular interaction within the ASD system plays a role in the level of apparent solubility, physical stability, and concentration of free drug available in an aqueous environment. Juvenile porcine models at two different weight groups (10 and 20 kg) were used to obtain the pharmacokinetic parameters of lapatinib. While the dose-normalized exposure of drug was found to be lower in the pig study, the dose flexibility of mini-tablets enabled a constant dose level to be administered to achieve equivalent plasma concentration-time profiles between the two groups. This linear scaling in the amount of drug in pediatric and adult population has also been observed in human clinical studies.

Tableting of mini-tablets in comparison with conventionally sized tablets: A comparison of tableting properties and tablet dimensions

Mini-tablets are solid dosage forms with increasing interest for pharmaceutical industry due to clinical and biopharmaceutical benefits. But technological aspects on mini-tableting are not fully investigated. Therefore, the impact of punch size and tableting pressure for industrially relevant excipients like microcrystalline cellulose, lactose, isomalt and Ludiflash® are investigated using 8 and 11.28 mm punches for conventionally sized tablets and 1,2 and 3 mm punches for mini-tablets. For evaluation of the effect of tablet size on deformation behaviour and mechanical properties, compressibility, compactibility and tabletability plots are created and evaluated. Deformation behaviour is analysed by In-Die Heckel plot and modified Weibull function. Further, specific plastic energy (SPE) profiles are generated out of force-displacement plots. The effect of the adjustment of the aspect ratio towards 1 as in conventionally sized tablets on deformation behaviour and tabletability is analysed. The effect of tablet size on deformation behaviour mainly showed lower yield pressures for conventionally sized tablets, whereas comparable SPEs were obtained with all tablet sizes. Furthermore, mini-tablets indicate better compactibility, as (depending on the excipient) higher tensile strengths were obtained at lower solid fractions. However, no superior tabletability properties are obtained for mini-tablets compared to conventionally sized tablets.

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Mini-tablets show higher compactibility compared to conventionally sized tablets.

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Mini-tablets show specific plastic energy profiles similar to conventional tablets.

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There is no trend for better tabletability for mini-tablets or conventionally sized tablets.

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Highest yield pressures are obtained with mini-tablets.

Study of drug particle distributions within mini-tablets using synchrotron X-ray microtomography and superpixel image clustering

Uniform drug distribution within fast disintegrating tablets is a key quality measure to ensure a reliable, steady, and targeted release of the contained active pharmaceutical ingredients. In this work, the drug particle distribution in mini-tablets was studied with synchrotron phase contrast X-ray microtomography. Mini-tablets had a weight of 9.5 mg and a drug load from 2.5% to 20%. Moxidectin, a drug used for treatment of parasitic infections, was used as a model compound. Drug content covered a range from 91% to 121% of the target dose. A linear iterative clustering (SLIC) superpixel method was used for segmentation, analysis, and visualization of the spatial distribution of individual tablet components (i.e., pores, excipients, and drug). Results show that the drug was not uniformly distributed within the tablet, revealing an increasing drug load towards the tablets' outer boundaries and thus indicative of a radial displacement of drug particles during compaction. The presented method can be used for the quantitative analysis of drug content and drug distribution within pharmaceutical tablets, allowing for the optimization of fast disintegrating formulations. The results also affirm that that drug loads up to 20% will not lead to segregation for moxidectin.

Comparison of multi-linear regression, particle swarm optimization artificial neural networks and genetic programming in the development of mini-tablets

In the present study, the preparation of pharmaceutical mini-tablets was attempted in the framework of Quality by Design (QbD) context, by comparing traditionally used multi-linear regression (MLR), with artificially-intelligence based regression techniques (such as standard artificial neural networks (ANNs), particle swarm optimization (PSO) ANNs and genetic programming (GP)) during Design of Experiment (DoE) implementation. Specifically, the effect of diluent type and particle size fraction for three commonly used direct compression diluents (lactose, pregelatinized starch and dibasic calcium phosphate dihydrate, DCPD) blended with either hydrophilic or hydrophobic flowing aids was evaluated in terms of: a) powder blend properties (such as bulk (Y1) and tapped (Y₂) density, Carr's compressibility index (Y₃, CCI), Kawakita's compaction fitting parameters a (Y₄) and 1/b (Y₅)), and b) mini-tablet's properties (such as relative density (Y₆), average weight (Y₇) and weight variation (Y₈)). Results showed better flowing properties for pregelatinized starch and improved packing properties for lactose and DPCD. MLR analysis showed high goodness of fit for the Y₁, Y₂, Y₄, Y₆ and Y₈ with RMSE values of Y₁ = 0.028, Y₂ = 0.032, Y₄ = 0.019, Y₆ = 0.015 and Y₈ = 0.130; while for rest responses, high correlation was observed from both standard ANNs and GP. PSO-ANNs fitting was the only regression technique that was able to adequately fit all responses simultaneously (RMSE values of Y₁ = 0.026, Y₂ = 0.022, Y₃ = 0.025, Y₄ = 0.010, Y₅ = 0.063, Y₆ = 0.013, Y₇ = 0.064 and Y₈ = 0.104).

Feasibility of mini-tablets as a flexible drug delivery tool

Mini-tablets have potential applications as a flexible drug delivery tool in addition to their generally perceived use as multi-particulates. That is, mini-tablets could provide flexibility in dose finding studies and/or allow for combination therapies in the clinic. Moreover, mini-tablets with well controlled quality attributes could be a prudent choice for administering solid dosage forms as a single unit or composite of multiple mini-tablets in patient populations with swallowing difficulties (e.g., pediatric and geriatric populations). This work demonstrated drug substance particle size and concentration ranges that achieve acceptable mini-tablet quality attributes for use as a single or composite dosage unit. Immediate release and orally disintegrating mini-tablet formulations with 30μm to 350μm (particle size d₉₀) acetaminophen and Compap™ L (90% acetaminophen) at concentrations equivalent to 6.7% and 26.7% acetaminophen were evaluated. Mini-tablets achieved acceptable weight variability, tensile strength, friability, and disintegration time at a reasonable solid fraction for each formulation. The content uniformity was acceptable for mini-tablets of 6.7% formulations with ≤170μm drug substance, mini-tablets of all 26.7% formulations, and composite dosage units containing five or more mini-tablets of any formulation. Results supported the manufacturing feasibility of quality mini-tablets, and their applicability as a flexible drug delivery tool.

Mini-tablets versus pellets as promising multiparticulate modified release delivery systems for highly soluble drugs

Whether mini-tablets (tablets, diameters ≤6mm) belong to single- or multiple-unit dosage forms is still questionable. Accordingly, Pharmacopoeial evaluation procedures for mini-tablets are lacking. In this study, the aforementioned points were discussed. Moreover, their potential for oral controlled delivery was assessed. The antidepressant venlafaxine hydrochloride (Vx), a highly soluble drug undergoing first pass effect, low bioavailability and short half-life was selected as a challenging payload. In an attempt to weigh up mini-tablets versus pellets as multiparticulate carriers, Vx-loaded mini-tablets were compared to formulated pellets of the same composition and the innovator Effexor(®)XR pellets. Formulations were prepared using various polymer hydrogels in the core and ethyl cellulose film coating with increasing thickness. Mini-tablets (diameter 2mm) showed extended Vx release (<60%, 8h). Indeed, release profiles comparable to Effexor(®)XR pellets were obtained. Remarkably higher coating thickness was required for pellets to provide equivalent retardation. Ethyl cellulose in the core ensured faster release due to polymer migration to the surface and pore formation in the coat. mini-tablets showed higher stability to pellets upon storage. Industrially speaking, mini-tablets proved to be superior to pellets in terms of manufacturing, product quality and economical aspects. Results point out the urgent need for standardized evaluation procedures for mini-tablets.

Design and evaluation of gastroretentive levofloxacin floating mini-tablets-in-capsule system for eradication of Helicobacter pylori

Gastroretentive levofloxacin (LVF) floating mini-tablets for the eradication of Helicobacter pylori (H. pylori) were prepared using the matrix forming polymer hydroxypropyl methylcellulose (HPMC K100M), alone or with Carbopol 940P in different ratios by wet granulation technique. Buoyancy of mini-tablets was achieved by an addition of an effervescent mixture consisting of sodium bicarbonate and anhydrous citric acid to some formulations. The prepared mini-tablets were evaluated for weight variation, thickness, friability, hardness, drug content, in vitro buoyancy, water uptake and in vitro release. The optimized formula was subjected to further studies: FT-IR, DSC analysis and in vivo examination in healthy volunteers. The prepared mini-tablets exhibited satisfactory physicochemical characteristics. Incorporation of gas-generating agent improved the floating parameters. HPMC K100M mini-tablet formulation (F1) offered the best controlled drug release (>8 h) along with floating lag time <1 s and total floating time >24 h. The obtained DSC thermograms and FT-IR charts indicated that there is no positive evidence for the interaction between LVF and ingredients of the optimized formula. The in vivo test confirmed the success of the optimized formula F1 in being retained in the stomach of the volunteers for more than 4 h. LVF floating mini-tablets based on HPMC K100M is a promising formulation for eradication of H. pylori.