Development of low dose micro-tablets by high shear wet granulation process

Automated process development with pure API filling using vacuum drum

In pharmaceutical development, dosing of pure active pharmaceutical ingredient (API) has proven to be essential for reducing API consumption and shortening early-stage development time, avoiding the need for excipients and compatibility studies. The vacuum drum filler, known for its precision in dosing down to 1 mg, is commonly employed for micro-dosing purposes, e.g., in the field of dry powder inhalation (DPI). In this study, however, it is desired to investigate the vacuum drum filler for its suitability in pure API filling. Automated Process Development (APD) integrates design of experiments (DoE) with automated execution to optimize processes efficiently. In this study, the APD method was investigated on the vacuum drum filling system to analyse the impact of various process parameters on the filling weight of capsules and the relative standard deviation (RSD) between the bores considering pure API. For this, two APIs were investigated: powdered paracetamol and micronized paracetamol. Notably, despite variations in vacuum and pressure, process parameters related to powder preparation in the chamber exerted the most significant influence. The 3-wire stirrer, located in the chamber on top of the vacuum drum, resulted in better filling weights and lower RSD with both powders. The APD method allowed to identify the parameters that minimized the RSD in the capsule filling of pure powdered paracetamol, emphasizing the need for tailored parameter optimization. Further investigation is needed to determine how to achieve optimal powder preparation in the chamber for micronized paracetamol.

The revival of the mini-tablets: Recent advancements, classifications and expectations for the future

Mini-tablets have recently raised huge interest in pharmaceutical industry. The present review aims to identify the rational, the opportunities and challenges of this emerging small solid drug dosage form by a structured literature review following the PRISMA algorithm. In total, more than 5,000 literature and patent sources have been found starting with the very first in the 60s of the past century, followed by the first multiparticular products using mini-tablets with pancreatin (Panzytrat® by the former BASF subsidiary Knoll/Nordmark) authorized in 1985. There seems to be a second boost of common interest in the 2000s when clinical studies demonstrated that one or more mini-tablets could enable superior drug administration even in very young patients including neonates over the former gold standard, a liquid drug preparation. Several pharmaceutical companies immediately started clinical development programs using the mini-tablet concept and the first products have been recently authorized by the competent authorities. Superiority was given as the mini-tablets ease the swallowing procedure compared to conventional tablets, enable various modified drug release opportunities including taste-masking by film-coating technology and provide excellent drug stability compared to liquid oral dosage forms. Due to these product attributes they are particularly beneficial to children and their caregivers. Furthermore, there is potential for precise individual drug dosing by counting adequate amounts of the multiple drug carriers. Most recently, two novel products with different concepts were authorized by the EMA and entered the market which are highlighted in this review: the first orodispersible mini-tablet with enalapril maleate for congenital heart failure (Aqumeldi® from Proveca Pharma) and the first single unit mini-tablet with matrix-type controlled melatonin release for insomnia (Slenyto® from Neurim Pharmaceuticals). Our review reveals, that the majority of the published scientific papers use co-processed, ready-to-use excipients for the orodispersible mini-tablet formulations. However, traditional fillers such as microcrystalline cellulose or lactose have also been used for immediate release mini-tablets after adding a (super)disintegrant and a lubricant. The manufacturing of mini-tablets is conducted on conventional rotary tablet presses, predominantly equipped with multi-tip toolings to improve the yield or production speed. Scaling-up has been successfully realized from compaction simulators to pilot and production scale. Film-coatings enabling gastric resistance, taste masking or sustained-release properties have been realized in both fluid-bed and drum coaters using the same polymers as for conventional tablets. There is still a significant lack in regulatory guidance despite the recent success of the mini-tablet concept, starting from suitable characterization methods in the pharmacopoeias up to the design and conduct of clinical studies on mini-tablets.

A Formulation-Process-Product Integrated Design Method for Accelerating Pharmaceutical Tablet Development via the High-Shear Wet Granulation and Tableting Route

Background/Objectives: Tablet is the most popular oral solid dosage form, and high-shear wet granulation and tableting (HSWGT) is a versatile technique for manufacturing tablets. The conventional pharmaceutical development for HSWGT is carried out in a step-by-step mode, which is inefficient and may result in local optimal solutions. Inspired by the co-design philosophy, a formulation-process-product integrated design (FPPID) framework is innovatively brought forward to enable the target-oriented and simultaneous exploration of the formulation design space and the process design space. Methods: A combination of strategies, such as a material library, model-driven design (MDD), and simulation-supported solution generation, are used to manage the complexity of the multi-step development processes of HSWGT. The process model was developed at the intermediate level by incorporating dimensionless parameters from the wet granulation regime map approach into the process of the partial least square (PLS) model. The tablets tensile strength (TS) and solid fraction (SF) could be predicted from the starting materials' properties and process parameters. The material library was used to diversify the model input and improve the model's generalization ability. Furtherly, the mixture properties calculation model and the process model were interconnected. Results: A four-step FPPID methodology including the target definition, the formulation simulation, the process simulation, and the solution generation was implemented. The performance of FPPID was demonstrated through the efficient development of high-drug-loading tablets. Conclusions: As a holistic design method, the proposed FPPID offers great opportunity for designers to handle the complex interplay in the sequential development stages, facilitate instant decisions, and accelerate product development.

The impacts of roller compaction on the quality attributes of simultaneously compressed micro and minitablets

The challenges of developing good quality low dose minitablets was assessed by systematically studying the effects of ibuprofen (IBU, a model compound) particle sizes (6-58 µm D50) and concentrations (0.1-3 %w/w), roller compaction forces (3-7 kN/cm), and the minitablet sizes (1.2, 1.5 and 2 mm diameter). A novel compression approach, where all three minitablet sizes were simultaneously produced in a single compression run was used. Roller compacted ribbons, granules, minitablets were characterized for physico-mechanical properties and minitablets were also characterized for stratified content uniformity and weight uniformity. The results showed that roll force was the more dominant factor to ribbon solid fraction or tensile strength and granule size enlargement. Minitablets obtained from the granules had good weight uniformity; all but one batch met the criteria. The precise control of tooling lengths across the various sizes was found profoundly important for achieving expected weights, solid fraction, and tensile strength of the simultaneously produced minitablets. The roller compaction process considerably improved the CU variability of the minitablets as compared to the direct compression process. Smaller particle size and higher concentration of IBU, increased roller compaction force, and larger minitablet size improved the potency and content uniformity; however, only the minitablet size was a statistically significant factor in this study. As a product strategic design criterion, a threshold of 25 minitablets in a dosage unit would ensure robust downstream filling and weight verification operations as well as dose accuracy and uniformity (would pass stage 1 criteria). This study results demonstrated feasibility of the novel simultaneous compression approach and the roller compaction process in developing good quality minitablets.

Novel Fimasartan Fluidized Solid Dispersion and Its Tablet: Preparation, Crystallinity, Solubility, Dissolution, and Pharmacokinetics in Beagle Dogs

BACKGROUND AND OBJECTIVES

Fimasartan, an angiotensin II receptor antagonist, exhibits low bioavailability due to its poor solubility; consequently, using solubilization technologies is essential to improve its bioavailability. In this study, novel fimasartan fluidized solid dispersion (FFSD) was developed using a fluid bed granulator to enhance the drug solubility and oral bioavailability.

METHODS

An appropriate FFSD was prepared in 50% ethanol using a fluid bed granulator, and its drug dissolution, morphology, and crystallinity were evaluated in comparison to the powdered drug. Moreover, the dissolution in various pH conditions and pharmacokinetics of the FFSD tablet in beagle dogs were investigated compared to the commercial fimasartan tablet.

RESULTS

Among the hydrophilic polymers tested, hydroxypropyl methylcellulose (HPMC) showed the highest solubility. The FFSD, composed of fimasartan, HPMC, and microcrystalline cellulose at the weight ratio of 20:10:25, gave a granular aggregation of several particles with a smooth surface. The drug in this FFSD existed as an amorphous state, leading to a greatly increased drug dissolution. The FFSD tablet was prepared by compressing a mixture of FFSD, mannitol, croscarmellose sodium, and magnesium stearate at the weight ratio of 55:40:5:1. The FFSD tablet gave significantly higher drug dissolution, plasma concentrations, maximum plasma concentration (Cmax) and area under the whole blood concentration-time curve (AUC) values than did the commercial fimasartan tablet. In the beagle dogs, the FFSD tablet (140.39 ± 27.40 ng·h/ml) had about a 1.7-fold higher AUC than the commercial fimasartan tablet (80.58 ± 22.18 ng·h/ml), indicating an enhancement in the bioavailability.

CONCLUSIONS

This novel FFSD tablet could be a potential oral pharmaceutical product with the improved oral bioavailability of fimasartan.

Current State of Minitablet Product Design: A Review

Interest in minitablets (MTs) has grown exponentially over the last 20 years and especially the last decade, as evidenced by the number of publications cited in Scopus and PubMed. MTs offer significant opportunities for personalized medicine, dose titration and flexible dosing, taste masking, and customizing drug delivery systems. Advances in specialized MT tooling, manufacturing, and characterization instrumentation have overcome many of the earlier development issues. Breakthrough MT swallowability, acceptability, and palatability research have challenged the long-standing idea that only liquids are acceptable dosage forms for infants and young children. MTs have been shown to be a highly acceptable dosage form for infants, small children, and geriatric patients who have difficulty swallowing. This review discusses the current state of MT applications, acceptability in pediatric and geriatric populations, medication adherence, manufacturing processes such as tableting and coating, running powder and tablet characterization, packaging and MT dispensing, and regulatory considerations.

Effects of wet granulation process variables on the quantitative assay model of transmission Raman spectroscopy for pharmaceutical tablets

Transmission Raman spectroscopy (TRS) is a process analytical technology tool for nondestructive analysis of drug content in tablets. Although wet granulation is the most used tablet manufacturing method, most TRS studies have focused on tablets manufactured via direct compression. The effects of upstream process parameter variations, such as granulation, on the prediction performance of TRS quantitative models are unknown. We evaluated the effects of process parameter variations during granulation on the prediction performance of the TRS quantitative model. Tablets with a drug concentration of 1%w/w were used. We developed PLS calibration models for the drug concentration range of 70-130% label claims. Subsequently, we predicted the drug content of the tablets with different granulation parameters. The results of our study demonstrate that the variation in the predicted recovery due to the variation in granulation parameters was practically acceptable. The calibration model showed a good prediction performance for tablets manufactured at different granulation scales and thicknesses. Therefore, we conclude that TRS quantitative models are robust to variations in upstream processes, such as granulation and downstream variations in tableting parameters. These results suggest that TRS is a versatile non-destructive quantitative analysis method that can be applied in tablet manufacturing.

Development and Optimization of Sildenafil Orodispersible Mini-Tablets (ODMTs) for Treatment of Pediatric Pulmonary Hypertension Using Response Surface Methodology

The availability of age-appropriate oral dosage forms for pediatric patients has remained a challenge. Orodispersible mini-tablets (ODMTs) are a promising delivery system for pediatric patients. The purpose of this work was the development and optimization of sildenafil ODMTs as a new dosage form for the treatment of pulmonary hypertension in children using a design-of-experiment (DoE) approach. A two-factor, three levels (32) full-factorial design was employed to obtain the optimized formulation. The levels of microcrystalline cellulose (MCC; 10–40% w/w) and partially pre-gelatinized starch (PPGS; 2–10% w/w) were set as independent formulation variables. In addition, mechanical strength, disintegration time (DT), and percent drug release were set as critical quality attributes (CQAs) of sildenafil ODMTs. Further, formulation variables were optimized using the desirability function. ANOVA analysis proved that MCC and PPGS had a significant (p < 0.05) impact on CQAs of sildenafil ODMTs with a pronounced influence of PPGS. The optimized formulation was achieved at low (10% w/w) and high (10% w/w) levels of MCC and PPGS, respectively. The optimized sildenafil ODMTs showed crushing strength of 4.72 ± 0.34 KP, friability of 0.71 ± 0.04%, DT of 39.11 ± 1.03 s, and sildenafil release of 86.21 ± 2.41% after 30 min that achieves the USP acceptance criteria for ODMTs. Validation experiments have shown that the acceptable prediction error (<5%) indicated the robustness of the generated design. In conclusion, sildenafil ODMTs have been developed as a suitable oral formulation for the treatment of pediatric pulmonary hypertension using the fluid bed granulation process and the DoE approach.

Mini-tablets as technological strategy for modified release of morphine sulfate

The aim of this study was to use intelligent formulation design for development of mini-tablets for modified release of morphine sulfate. A formulation (F1) was proposed using the Hiperstart® software. Based on the suggested formulation, two other formulations (F2 and F3) were prepared: one for modified and another for immediate drug release. The powders were characterized as bulk and tapped density, Hausner's factor and compressibility index analyzes. Mini-tablets were directly compressed and characterized as hardness, friability, size, and weight variation. The in vitro drug release profile was carried out according to the apparatus 1 of USP. Formulations showed good flow properties, and the mini-tablets displayed characteristics according to the specified. In comparison to F3 (immediate release), F1 and F2 displayed slower drug release time, showing the efficiency of the matrix formed. F3 displayed 90% of drug released up to 10 min, while F1 and F2 required 240 min. The results highlight the importance to use intelligent formulation design for the development of improved mini-tablet matrices. Formulation F1 was found to be suitable for modified morphine sulfate release. Further studies with more formulations are necessary for production of optimized mini-tablets with suitable prolonged morphine sulfate release.

Innovative, Sugar-Free Oral Hydrogel as a Co-administrative Vehicle for Pediatrics: a Strategy to Enhance Patient Compliance

Palatability and swallowability in the pediatric population are perceived as true challenges in the oral administration of medication. Pediatric patients have high sensitivity to taste and reduced ability to take solid dosage forms, which can often lead to a poor therapeutic compliance. It is crucial to find new strategies to simplify the oral administration of drugs to children. The present paper reports the development of a new hydrogel vehicle adapted to the pediatric population. Several polymers with similar properties were selected and adjustments were made to obtain the desired characteristics of the final product. The developed formulations were studied for organoleptic properties, rheology, mucoadhesion properties, preservative efficacy, and stability. Physical and chemical compatibilities between the vehicle and several drugs/medicines, at the time of administration, were also studied. Six final formulations with different polymers, odor, and color were chosen, and no known interactions with medications were observed. The proposed new oral vehicles are the first sugar-free vehicle hydrogels designed to make the intake of oral solid forms a more pleasant and safer experience for pediatric patients.

Pharmaceutical Development of Film-Coated Mini-Tablets with Losartan Potassium for Epidermolysis Bullosa

Epidermolysis bullosa is a genetically heterogenous skin fragility disorder with multiorgan involvement appearing already in newborn children. Severe progressive fibrosis follows skin blistering, mucosa lesions, and wound healing, favouring development of highly aggressive squamous cell carcinomas. Losartan potassium (LP) has been described to show positive effects; therefore, it was of clinical interest to develop 2 mm mini-tablets with LP for treatment of the affected children. Several challenges emerged during development: limited flowability and sticking to punches were observed in the first tableting experiments due to a high drug load, and a bitter taste of the LP was reported. Sticking to punches was reduced by using SMCC 50 and a combination of different lubricants; however, direct compression trials on a Korsch XM 12 rotary press were not successful due to compaction phenomena in the hopper. Thus, an intermediate dry granulation was successfully introduced. Two final formulations of the mini-tablets complied with the requirements of the European Pharmacopoeia regarding disintegration times (<15 min) and friability (<1.0%); mean tensile strengths amounted to about 1 MPa as a compromise between manufacturability and sufficient mechanical strength for further coating studies. The subsequent coating step succeeded delaying the initial drug release for more than 2 min. An acceptance value ≤15 was matched for the coated mini-tablets, and stability studies showed a promising shelf life.

Mini-Tablets: A Valid Strategy to Combine Efficacy and Safety in Pediatrics

In the treatment of pediatric diseases, mass-produced dosage forms are often not suitable for children. Commercially available medicines are commonly manipulated and mixed with food by caregivers at home, or extemporaneous medications are routinely compounded in the hospital pharmacies to treat hospitalized children. Despite considerable efforts by regulatory agencies, the pediatric population is still exposed to questionable and potentially harmful practices. When designing medicines for children, the ability to fine-tune the dosage while ensuring the safety of the ingredients is of paramount importance. For these purposes solid formulations may represent a valid alternative to liquid formulations for their simpler formula and more stability, and, to overcome the problem of swelling ability, mini-tablets could be a practicable option. This review deals with the different approaches that may be applied to develop mini-tablets intended for pediatrics with a focus on the safety of excipients. Alongside the conventional method of compression, 3D printing appeared particularly appealing, as it allows to reduce the number of ingredients and to avoid both the mixing of powders and intermediate steps such as granulation. Therefore, this technique could be well adaptable to the daily galenic preparations of a hospital pharmacy, thus leading to a reduction of the common practice of off-label preparations.

A Novel Use of Nanocrystalline Suspensions to Develop Sub-Microgram Dose Micro-Tablets

Developing solid oral drug products with good content uniformity (CU) at low doses is challenging; this challenge further aggravates when the tablet size decreases from a conventional tablet to a micro/mini-tablet (1.2-3 mm diameter). To alleviate the CU issues, we present a novel use of nanocrystalline suspension combined with high shear wet granulation for the first time. In this approach, nanomilled drug in the form of nanocrystalline suspension is sprayed onto the powder bed to ensure uniform distribution. The resulting granules had adequate particle size distribution and flow characteristics to enable manufacturing of micro-tablets with good weight uniformity and tensile strength. Nanomilled drug resulted in excellent content uniformity among individual micro-tablets even at a dose strength as low as 0.16 mcg, whereas micronized drug resulted in unacceptable CU even at 5x higher dose strength (0.8 mcg). Besides, the use of nanomilled drug has enhanced the dosing flexibility of micro-tablets and showed superior dissolution performance in comparison with micronized drug with no impact of storage conditions (40 °C/75%RH for six months) on their dissolution performance. The proposed approach is simple and can be easily incorporated into traditional high shear wet granulation process to develop sub-microgram dose solid oral drug products.

Strategies and formulations of freeze-dried tablets for controlled drug delivery

The freeze-drying process has been particularly attractive for preparing tablets for controlled drug release. Although traditional methods, such as granulation or direct compression methods, have been used in various studies to produce tablets with controlled release, freeze-drying processes have been utilized in certain circumstances due to their distinct advantages. However, overall, further development of these strategies, which started with early studies on orally disintegrating tablets, is still necessary. In this review, the incorporation of different formulations into freeze-dried tablets will be discussed. Moreover, the use of excipients, freeze-drying conditions, formulation reconstitution and tablet structure for optimizing the performance of freeze-dried tablets will be reported, including strategies with nanoformulations and natural materials. Generally, this discussion with potential approaches will benefit further development of freeze-dried tablets containing drugs in the pharmaceutical industry.

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.