Controlled release is a subform of modified release. The pharmaceutical formulation is arranged, such that the API release follows a defined release profile.

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Patent on controlled release formulations of highly lipophilic physiologically active substances

The patent application US20240139215A1 focuses on the development of controlled release formulations for highly lipophilic physiologically active substances, such as cannabinoids. These substances tend to have high lipid solubility (log P of 4 or more), making them difficult to deliver in a controlled and effective manner. This patent addresses the need for efficient controlled release systems that can provide consistent therapeutic effects by utilizing a matrix-based approach.

The formulation includes a matrix that contains one or more highly lipophilic active substances and water-soluble binders like hydroxypropyl methyl cellulose (HPMC), methyl cellulose (MC), or similar polymers. The key challenge with such substances is their tendency to release slowly and incompletely when taken orally, which this patent solves by adjusting the proportion of water-soluble binders. The binder content is carefully selected to be between 0.1-10% of the total matrix weight, optimizing the release rate of the active substances over the gastrointestinal transit time.

One of the innovative aspects of the invention is the use of matrix pellets, which are small particles with a size range of 30 µm to 1800 µm. These pellets may be administered in various forms, such as capsules, tablets, or sachets. The flexibility of the dosage forms makes it easier to control and adjust the release kinetics of the active ingredients.

The CELLETS® play a crucial role in this formulation. They are used as neutral cores for the deposition of the active substances and their binders. CELLETS® are microcrystalline cellulose spheres that provide an ideal substrate for layering the active substance and polymers, ensuring uniform distribution and controlled release. By using these CELLETS®, the formulation can achieve a more predictable and consistent release profile, crucial for substances like cannabinoids that require precise dosing to avoid psychoactive side effects while maintaining therapeutic efficacy.

Additionally, these pellets can be coated with other materials to further control the release rate if desired, though this is optional. In many embodiments, the matrix pellets themselves are sufficient to achieve the desired controlled release without the need for additional coatings.

In conclusion, the US20240139215A1 patent introduces a novel approach to the controlled release of highly lipophilic substances, leveraging matrix technology with carefully chosen water-soluble binders and neutral cores like CELLETS®. This method ensures effective delivery and consistent release, addressing the challenges posed by the lipophilic nature of substances like cannabinoids. In this specific patent, the following MCC Sphere types are recommended: CELLETS® 500.

Document information

Document Type and Number: (“Controlled release formulations of highly lipophilic physiologically active substances”)
Kind Code: A1

Inventors:

Mirko Nowak
Jay Jesko Nowak
Annette Grave
Monika Wentzlaff
Sarah Barthold
Christian Geugelin

Disclaimer

This text was generated by chatGPT engine version GPT‑4o, on Oct 21, 2024. Image was generated with Adobe Firefly.

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Figure 2: SEM image of drug loaded and coated starter beads. Particles show a high level of homogeneity in size distribution.

Microparticle coating in Wurster Fluidized Bed – Scalable Production of Oral Sustained-Release Drugs

Abstract

Modified drug release formulations for suspensions are a perfect solution for children and patients with swallowing difficulties. In many cases, these formulations are based on pellets serving as starter beads. In this report, an attempt on microparticle coating by Mohylyuk et al. [1] is described. Herein, small scaled microcrystalline cellulose pellets (Cellets® 90 and Cellets® 100, Table 1) in the size range smaller than 150 µm are used. Through a modified Wurster fluidized bed process, a yield of 99 % was reached.

Starter materials PSD (> 85 %)
Cellets® 90 63-125 μm
Cellets® 100 100-200 µm

Table 1: Size distribution of Cellets® as starter beads in this formulation.

Goals and Formulation

The goal is to investigate a revolutionary platform for sustained-release microencapsulation using the industrial fluidized bed coating technology. Significant challenges of particle cohesion in the process shall be avoided by applying a small quantity of dry powder glidant periodically during the coating process. A highly water-soluble drug, which is metoprolol succinate, is reproducibly microencapsulated on pellet technologies with total pellet sizes of less than 200 µm and a drug release time of 20 hours.

Excipients for extended release profiles

For obtaining a sustained release profile, polymethacrylate-based copolymers, Eudragit RS/RL® 30 D and Eudragit® NM 30 D, were used in combination with a range of anti-tacking agents. The coating onto placebo Cellets® 100 starter beads was performed in a fluidized bed coater with a Wurster insert (Mini-Glatt, Glatt GmbH, Germany) in order to analyze the release profile. Process parameters are shown in Table 2. A small quantity of dry powder glidant was periodically added during processing, so that particle cohesion was eliminated. The optimized excipient composition for the desired release profile is achieved by testing 10 different compositions.

Parameter Value
Inlet air temperature
 Eudragit RS/RL® 30 D 35-40 °C
 Eudragit® NM 30 D 30-35 °C
Product temperature
 Eudragit RS/RL® 30 D 25-30 °C
 Eudragit® NM 30 D 18-20 °C
air flow rate 18 m3/h
Atomization pressure 1.5 bar
Spray rate 1.1-2.4 g/min

Table 2: Process parameter for a fluidized bed coater with a Wurster insert. A sustained release drug layer is coated onto placebo Cellets® 100 starter beads.

Drug coating

For drug coating, Cellets® 90 were layered with a suspension of metoprolol succinate in a composition as shown in Table 3.

Material Concentration (w/w)
Metoprolol succinate 22.8 %
Hypromellose 0.6 %
talc (Pharma M) 4.0 %
Deionized water 72.6 %

Table 3: Composition of metoprolol succinate suspension for drug layering onto Cellets® 90.

The metoprolol succinate-loaded Cellets® 90 microparticles were successfully coated with the Eudragit® NM 30 D based aqueous dispersion, achieving a high product yield of 99 % and a final particle size of less than 200 µm (D50 value).

Figure 1: Size distribution of Cellets® 90 as uncoated (empty squares), drug loaded (filled diamonds) and drug loaded and coated (filled circles) particles.

Figure 1: Size distribution of Cellets® 90 as uncoated (empty squares), drug loaded (filled diamonds) and drug loaded and coated (filled circles) particles.

The API loaded and coated starter beads are of high sphericity and show a homogeneous and narrow size distribution, which is shown as a SEM (scanning electron microscope) image in Figure 2.

In dissolution tests, an extended release time of up to 20 hours is obtained and can still be varied by the composition of excipients (Figure 3).

Figure 2: SEM image of drug loaded and coated starter beads. Microparticles show a high level of homogeneity in size distribution.

Figure 2: SEM image of drug loaded and coated starter beads. Microparticles show a high level of homogeneity in size distribution.

Figure 3: Drug release profiles of three batches of metoprolol succinate loaded and coated Cellets. An extended release of 20 hours is obtained.

Figure 3: Drug release profiles of three batches of metoprolol succinate loaded and coated Cellets. An extended release of 20 hours is obtained.

Summary

This case study is a short abstract of the publication on microparticle coating by Mohylyuk et al. [1], highlighting the proof of concept for reproducible microencapsulation of a highly water-soluble drug by applying a small quantity of dry powder glidant periodically during Wurster fluidized bed coating. The challenge of particle cohesion in the “down flow” zone was eliminated and a high product yields up to 99% was achieved.

Coated microparticles are in size of less than 200 μm and show a 20 hours sustained drug release profile. These conditions allow the usage in liquid suspensions. Furthermore, the applied technology is scalable. In conclusion, this displays a sustained-release dosage solution, which is suitable for paediatrics and geriatrics with swallowing difficulties.

Acknowledgement

Dr. Fang Liu and her team are gratefully acknowledged for serving content and data for this note.

Fluid Pharma logo

Fluid Pharma Ltd

Contact: Dr. Fang LIU

College Lane, Hatfield, AL10 9AB, UK

Tel: +44 1707 28 4273

+44 796 3230 628

www.fluidpharma.com

References

[1] V. Mohylyuk et al., AAPS PharmSciTech (2020) 21:3

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