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Multilayered pharmaceutically active compound-small

Introduction to Multilayered Pharmaceutically Active Compound Technology

Multilayered pharmaceutically active compound-releasing microparticles in a liquid dosage form represent an innovative approach to oral drug delivery. This technology combines the benefits of coated pellets with the convenience of liquid administration. Effervescent tablets are solid dosage forms that release carbon dioxide when they dissolve in water. This reaction results from the interaction between an acid source, such as citric acid, and a carbonate or bicarbonate salt. Patients consume the resulting solution or suspension immediately after preparation. Consequently, effervescent tablets improve ease of administration and often enhance patient compliance.

Pellets play an increasingly important role in modern effervescent tablet formulations. Unlike conventional powder blends, pellets can carry individual functional coatings that protect active pharmaceutical ingredients (APIs) from degradation. In addition, pellets can separate incompatible ingredients within the same dosage form. They also improve taste masking and enable modified-release properties. As a result, formulators can develop more stable and effective products. Furthermore, pellet-containing effervescent tablets often reduce gastrointestinal irritation and improve dose uniformity. These advantages benefit both the final pharmaceutical product and the patient.

Multilayered pharmaceutically active compound-large

Multilayered pharmaceutically active compound-large

Summary of EP3117824A1

The European patent EP3117824A1 describes a drug delivery platform based on multilayered pharmaceutically active compound-releasing microparticles suspended in a liquid dosage form. The invention addresses a major challenge in pharmaceutical formulation. Many controlled-release and enteric-coated particles lose functionality when they remain in contact with water for extended periods. Therefore, maintaining stability during storage becomes difficult.

The patented technology uses microparticles that contain an API-loaded core surrounded by multiple functional coating layers. A controlled-release or enteric coating forms the intermediate layer. An additional outer protective layer surrounds this coating. The inventors designed this outer layer from a combination of hydrophilic and hydrophobic materials. Consequently, the layer protects the underlying release-controlling membrane from premature exposure to the liquid environment.

During storage, the protective coating minimizes drug leakage and preserves the integrity of the controlled-release system. As a result, the microparticles maintain their desired release characteristics for extended periods. Once the patient administers the formulation, the outer coating dissolves rapidly in the stomach. Subsequently, the underlying controlled-release coating resumes its intended function. This mechanism allows the formulation to deliver the API at a predefined location or rate within the gastrointestinal tract.

The invention offers particular advantages for drugs that require modified release, intestinal targeting, or protection from acidic gastric conditions. In addition, the technology supports the development of patient-friendly liquid formulations. This feature benefits pediatric, geriatric, and dysphagic patients who often struggle to swallow tablets or capsules. Overall, the patent combines the flexibility of pellet-based drug delivery with improved stability in aqueous dosage forms. Therefore, it represents an important advancement in oral pharmaceutical technology.

Impact of MCC spheres in this Patent

In EP3117824A1, CELLETS® or similar spherical starter cores serve as the fundamental substrate for producing the multilayered pharmaceutically active compound-releasing microparticles. These inert pellet cores, commonly composed of microcrystalline cellulose, provide a highly uniform and mechanically stable surface onto which drug-containing layers and subsequent functional coatings can be applied with high precision.

Their excellent sphericity promotes uniform coating thickness, which is critical for achieving reproducible controlled-release performance and minimizing variability between pellets. Furthermore, Cellets enable high drug loading while maintaining robust processing characteristics during fluid-bed coating operations.

Pellet size also plays an important role in the final product performance. Smaller pellets, typically in the range of 100–500 µm (such as CELLETS® 100, 200, 350), offer a larger surface area and can provide faster or more uniform drug release, whereas larger pellets, often between 500–1500 µm (such as CELLETS® 500, 700, 1000), facilitate the application of multiple coating layers and may support more sophisticated release profiles.

In addition, smaller pellets generally improve content uniformity and patient acceptability, especially in liquid and effervescent dosage forms, because they create a smoother mouthfeel and more homogeneous suspension. Therefore, selecting the appropriate Cellet size represents a key formulation parameter that influences coating efficiency, drug release kinetics, stability, and overall patient experience.

Acetylsalicylic Acid, Paracetamol, and Ascorbic Acid in Pellet-Based Effervescent Formulations

Although EP3117824A1 does not specifically focus on acetylsalicylic acid, paracetamol, or ascorbic acid, the technology applies well to these APIs. Acetylsalicylic acid, commonly known as aspirin, belongs to the nonsteroidal anti-inflammatory drug (NSAID) class. It treats pain, fever, inflammation, and cardiovascular disorders. Depending on the classification source and physiological conditions, aspirin generally falls within BCS Class I or Class III. Because aspirin can irritate the gastric mucosa, pellet-based controlled-release systems may improve gastrointestinal tolerability.

Paracetamol is an analgesic and antipyretic agent that treats pain and fever. It is generally classified as a BCS Class I compound due to its high solubility and permeability. Furthermore, pellet technology can improve taste masking and provide modified-release options. These properties make paracetamol formulations more suitable for pediatric and elderly patients.

Ascorbic acid, also known as vitamin C, functions as a water-soluble vitamin and antioxidant. Healthcare professionals use it to prevent and treat vitamin C deficiency. It exhibits high aqueous solubility and frequently appears in effervescent products. Moreover, pelletization can improve formulation stability by separating ascorbic acid from reactive ingredients. This approach may reduce degradation during storage and improve product quality.

Conclusion and Outlook

Multilayered pharmaceutically active compound technology offers a sophisticated solution for modern oral drug delivery. It combines coated pellet systems with liquid dosage forms while maintaining controlled-release functionality. Moreover, the technology supports improved stability, enhanced patient convenience, and flexible formulation design. When formulators incorporate pellets into effervescent tablets, they can protect sensitive APIs, reduce gastrointestinal side effects, and optimize therapeutic performance. As pharmaceutical research advances, multilayered pharmaceutically active compound systems will likely support more complex formulations and personalized treatment strategies. Consequently, this technology may become an increasingly important platform for next-generation oral medicines.

Patent Summary

  • Name of Patent: Multilayered pharmaceutically active compound-releasing microparticles in a liquid dosage form
  • Patent Number: EP3117824A1
  • Year of Patent: 2015
  • Patent Holders: Federica Ronchi, Jonathan Goole, Karim Amighi, Georges Guillaume, Vincent Stephenne
  • Affiliation: Be Pharbel Manufacturing
Particle Size Distributions of Inert Spheres

Introduction to Particle Size Distributions of Inert Spheres and Their Role in Pelletized Pharmaceutical Products

In pharmaceutical formulation science, Particle Size Distributions of Inert Spheres represent a fundamental quality attribute for multiparticulate dosage forms. Inert spheres, such as microcrystalline cellulose pellets, act as neutral carriers for active pharmaceutical ingredients. They enable precise drug layering, predictable dissolution, and uniform content distribution in capsules or tablets. A narrow and well-characterized PSD improves processability and coating uniformity. It also supports reproducible drug delivery performance in multiparticulate systems. Inert spheres such as CELLETS® offer tight PSD and high sphericity. Therefore, they provide robust cores for dosage forms ranging from low-dose products to extended-release multiparticulates.

A Publication Worth Reading: computerized image analysis

The publication by Heinicke and Schwartz [1] evaluates computerized image analysis for measuring PSD in pharmaceutical spheres and pellets. The study covers particle size ranges from approximately 425 to 1400 micrometers. Traditional sizing methods, such as sieve analysis, provide limited resolution and statistical detail. In contrast, image analysis demonstrated high repeatability and sensitivity. It quantified size differences that traditional methods could not detect. The authors compared two inert sphere lots before drug layering in a fluid-bed rotor granulator. Differences in starting PSD appeared clearly in the resulting granulated products. This result highlights the importance of core PSD for downstream performance. Furthermore, image analysis detected coating thickness increments as small as four micrometers.

The authors also investigated sampling strategies and sample sizes necessary for reliable measurements, recognizing that an appropriate representativeness of sample draws is critical for statistically meaningful PSD outcomes. Importantly, image analysis captured not only size distribution but also provided visual and morphological data for each particle, thereby enriching the dataset beyond mere dimensional statistics. The technique’s effectiveness was tested in both laboratory and commercial scale contexts, including measuring polymer-coated nonpareils during continuous fluid-bed processing. The similarity between in-situ samples (collected via process sampling ports) and whole batch samples suggested that fluid-bed processes in these systems provide sufficiently homogeneous conditions for representative PSD capture by image analysis.

Beyond the direct findings, the work situates PSD measurement via image analysis within a broader pharmaceutical quality landscape. Historically, PSD has been a critical parameter because it influences particle flow, coating behavior, drug layering uniformity, content uniformity, and ultimately drug release characteristics. The continuous development of in-line and at-line image analysis methods positions this approach as part of process analytical technology (PAT), enabling more dynamic control and monitoring of multiparticulate manufacturing.

Advances in Image Analysis for Determining Particle Size Distributions of Inert Spheres

Image analysis has evolved rapidly as a high-resolution method for determining PSD in pharmaceutical spheres. It directly measures individual particle dimensions and morphologies with high precision. Unlike sieve analysis or laser diffraction, image analysis provides particle-by-particle size and shape data. Therefore, it improves PSD accuracy, reproducibility, and visualization during development and quality control. Dynamic image analysis platforms process thousands of particles within minutes. As a result, they generate robust PSD and shape statistics correlated with functional performance criteria.

Important facts include the distinction between number-based and volume-based PSD measures. Metrics such as D10, D50, and D90 describe the spread and balance of the size distribution. In addition, image analysis extracts shape parameters such as sphericity and aspect ratio. These parameters strongly influence flow properties and coating behavior. Moreover,  image analysis enables rapid in-process feedback for monitoring and control. This capability supports coating thickness control and ensures batch-to-batch consistency.

Persisting Obstacles

Despite these advances, obstacles persist. Adequate sample preparation is essential to avoid overlapping particles and bias, especially when using static imaging methods. Agglomeration, depth-of-field effects, and segmentation challenges in image processing can introduce measurement uncertainty if not properly managed. Opportunities exist to integrate enhanced machine vision, artificial intelligence (AI), and real-time imaging to improve discrimination of individual particles in complex mixtures or in high-throughput manufacturing environments. In-line imaging systems with real-time analytics can transform PSD from a static quality attribute to a dynamic process performance indicator.

CELLETS® exemplify the concept of narrow PSD and high surface homogeneity in inert spheres. These microcrystalline cellulose pellets exhibit tight particle size distributions within specified fractions (e.g., 100–200 µm, 150–300 µm, up to 1000-1400 µm) with high sphericity, low friability, and consistent surface characteristics that enhance coating uniformity and enable predictable performance in multiparticulate dosage forms. The narrow PSD and uniform surface enable reproducible drug layering, optimized flow properties, and controlled release profiles, making them ideal cores in fluid bed and Wurster coating operations.

Particle Size Distributions of Inert Spheres

Conclusion and Outlook

The study by Heinicke and Schwartz underscores the value of image analysis for PSD determination. They compared traditional sizing methods with image analysis for inert spheres and coated pharmaceutical pellets. The detection of fine particle diameter differences and detailed morphology supports formulation design, process control, and quality assurance. Future image analysis developments, including AI and in-line PAT integration, will further enhance PSD measurement capabilities. These advances will enable real-time adjustments and closed-loop control in pellet manufacturing. As multiparticulate drug delivery advances, precise characterization of Particle Size Distributions of Inert Spheres remains essential. This precision supports consistent therapeutic outcomes, regulatory compliance, and manufacturing efficiency. Ongoing innovations in imaging hardware, software, and data analytics will strengthen real-time quality control and predictive modeling.

References

[1] G. Heinicke, J. B. Schwartz, Pharmaceutical Development and Technology 2005 (9) 4, 359-367, doi:10.1081/PDT-200032996

CELLETS pharmaceutical starter cores

CELLETS® Pharmaceutical Starter Cores for Pellets & Functional Coatings

CELLETS® are high-purity pharmaceutical starter cores. They combine spherical geometry with narrow particle size distribution and defined density. They provide reproducible carriers for functional coatings and enable controlled layer formation in fluid bed and drum coating processes. Thanks to their uniform geometry, CELLETS® ensure stable fluidization, consistent rolling, and homogeneous wetting during coating. This guarantees uniform layer thicknesses and precise control of active ingredient release.

In controlled-release applications—such as sustained-release, delayed-release, or gastro-resistant systems—CELLETS® support reproducible release profiles. They minimize variability in active ingredient application and polymer layer thickness, creating robust, scalable formulations. CELLETS® enable efficient transfer from formulation development to production scale, improving process reliability and batch-to-batch consistency.

Standardized Starter Cores for GMP-Compliant Processes

CELLETS® are manufactured under controlled conditions with reproducible physical properties. Their narrow particle size, defined density, and high sphericity support consistent process control. This facilitates equipment and process qualification. Regulatory documentation (e.g., DMF information) and GMP compatibility allow CELLETS® to be used across the entire product lifecycle. Using standardized starter cores reduces regulatory risks and supports process validation and batch consistency.

CELLETS pharmaceutical starter cores

Seamless Transfer from Development to Production

CELLETS® enable a smooth scale-up from lab to pilot and commercial production without altering material properties. This simplifies understanding and control of critical process parameters (CPPs). Formulations developed on CELLETS® can scale reproducibly, shortening development timelines and minimizing process adjustments.

Controlled Release & Enteric Coating Precision

CELLETS® provide a neutral, robust core for controlled or delayed drug release. Their uniform surface allows homogeneous application of functional polymer layers, such as sustained-release or enteric coatings. They reduce variability in layer thickness and drug distribution, ensuring reproducible release profiles. CELLETS® support the development of stable controlled-release and enteric coating systems in both R&D and commercial production.

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