Multilayered Pharmaceutically Active Compound-Releasing Microparticles in Effervescent Tablets

Introduction to the Multilayered Pharmaceutically Active Compound Concept

The Multilayered pharmaceutically active compound approach represents an advanced drug delivery strategy in which active pharmaceutical ingredients (APIs) are incorporated into coated microparticles or pellets that provide controlled, delayed, or site-specific release within the gastrointestinal tract. Effervescent tablets are solid dosage forms that rapidly dissolve in water through an acid–base reaction, typically involving citric acid and bicarbonate salts, producing carbon dioxide and a palatable oral solution or suspension before administration. The incorporation of pelletized drug delivery systems into effervescent tablets offers significant pharmaceutical and patient-centered advantages. Pellets can protect sensitive APIs from degradation, separate incompatible ingredients, improve taste masking, enable modified-release profiles, and reduce local gastrointestinal irritation. Furthermore, pellet-containing effervescent tablets enhance dose uniformity, facilitate administration for pediatric and geriatric populations, and improve treatment adherence by combining the convenience of a liquid dosage form with the stability of a solid formulation. These benefits make the Multilayered pharmaceutically active compound technology particularly attractive for modern oral drug delivery systems.

Summary of EP3117824A1: Multilayered Pharmaceutically Active Compound-Releasing Microparticles in a Liquid Dosage Form

The patent publication “Multilayered pharmaceutically active compound-releasing microparticles in a liquid dosage form” describes an innovative oral drug delivery platform designed to overcome the stability challenges associated with controlled-release microparticles dispersed in liquid media. The invention focuses on multilayer microparticles containing a pharmaceutically active compound within a core that is surrounded by a controlled-release intermediate coating and an additional outer protective coating. This external layer consists of a combination of a gastro-soluble hydrophilic polymer and a hydrophobic or insoluble component, creating a barrier that protects the controlled-release system during storage in aqueous environments. Google Patents EP3117824A1

A key innovation of the patent is the ability to maintain chemical and physical stability of the API while the microparticles remain suspended in a liquid dosage form for extended periods. Traditional enteric-coated particles often lose functionality when stored in aqueous suspensions because the coating can dissolve prematurely. The patented system prevents such degradation and minimizes API leakage into the surrounding liquid, thereby preserving the intended release profile. The inventors report that the formulation can maintain stability for several days or even weeks while limiting premature drug release to very low levels.

The technology is particularly suitable for acid-labile drugs, gastric-irritating compounds, sustained-release medications, and drugs requiring intestinal or colonic targeting. The microparticles typically employ pellet cores composed of materials such as microcrystalline cellulose, onto which drug-containing and functional coating layers are applied using fluid-bed coating and related pharmaceutical processing techniques. Once administered, the outer protective layer rapidly disappears in the stomach, restoring the original controlled-release properties of the pellet system. This design enables patients who have difficulty swallowing tablets or capsules to receive modified-release medications in a liquid format without compromising therapeutic performance.

The Impact of CELLETS® on this Application

In EP3117824A1, CELLETS® act as inert spherical cores that form the foundation of the multilayer microparticles. Their uniform shape enables precise drug layering and coating, which ensures consistent release behavior and formulation stability. Pellet size is also important: smaller pellets provide a larger surface area and smoother suspension properties, while larger pellets facilitate the application of multiple functional coatings and more complex release profiles. Therefore, CELLETS® play a key role in product performance, stability, and patient acceptance.

API Considerations: Acetylsalicylic Acid, Paracetamol, and Ascorbic Acid

The patent does not specifically focus on acetylsalicylic acid, paracetamol, or ascorbic acid as primary model drugs; however, the described technology is highly relevant to such compounds. Acetylsalicylic Acid is a nonsteroidal anti-inflammatory drug (NSAID) used for pain, fever, inflammation, and cardiovascular protection. It is generally classified as a Biopharmaceutics Classification System (BCS) Class I or Class III drug depending on formulation and ionization conditions. Because aspirin may irritate the gastric mucosa, controlled-release pellet systems can reduce localized stomach exposure and improve tolerability.

Paracetamol is a widely used analgesic and antipyretic agent commonly classified as a BCS Class I drug due to its high solubility and permeability. It is primarily indicated for the treatment of mild-to-moderate pain and fever. Pelletized formulations may enable taste masking, modified release, and improved patient compliance, particularly in pediatric populations.

Ascorbic Acid is a water-soluble vitamin and antioxidant generally categorized as a highly soluble compound. It is used for prevention and treatment of vitamin C deficiency and is frequently included in effervescent formulations. In pellet-containing effervescent tablets, ascorbic acid may benefit from improved stability and compatibility when physically separated from other reactive ingredients.

Conclusion and Outlook

The Multilayered pharmaceutically active compound technology described in EP3117824A1 represents a significant advancement in oral controlled-release drug delivery. By combining multilayer-coated pellets with liquid dosage forms, the invention addresses longstanding challenges related to API stability, controlled release, and patient convenience. The approach is especially promising for incorporation into effervescent tablet systems, where pellet technology can protect sensitive APIs, improve gastrointestinal tolerability, and enhance therapeutic performance. Future developments are likely to expand the application of multilayer microparticles to increasingly complex drug combinations, personalized medicines, and patient-friendly dosage forms that unite the advantages of liquid administration with sophisticated controlled-release functionality.

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