Solventless dry powder coating for sustained drug release using mechanochemical treatment based on the tri-component system of acetaminophen, carnauba wax and glidant

Preparation of sustained-release tablets using a solventless-mixing tablet coating technique: Particle design of dry ammonioalkyl methacrylate copolymer latex with high coating performance using sodium lauryl sulfate

The aim of this study was to produce sustained-release tablets by V-shaped blending of polymer and tablets without using solvents or heating, and we investigated the design of polymer particles with high coating performance by modifying the structure of the particles using sodium lauryl sulfate. Dry-latex particles of ammonioalkyl methacrylate copolymer were prepared by adding the surfactant into aqueous latex, followed by freeze drying. The resulting dry latex was mixed with tablets (1:10) using a blender and the resulting coated tablets were characterized. Tablet coating by the dry latex was promoted as the weight ratio of surfactant to polymer increased. At a surfactant ratio of 5%, deposition of the dry latex was most effective and the resulting coated tablets (annealed at 60 °C/75%RH for 6 h) exhibited sustained-release characteristics over a period of 2 h. The addition of SLS prevented coagulation of colloidal polymer in the freeze drying, resulting in a loose-structured dry latex. This latex was easily pulverized by V-shaped blending with tablets and the resulting fine particles with high adhesiveness were deposited on the tablets. However, at a surfactant ratio of 10%, the coating of dry latex decreased due to reduced adhesiveness.

Design and preparation of nanocomposite acrylate coating agents for binder-free dry coating of 100 µm-sized drug-containing particles and their coating performance

For binder-free dry particulate coating to prepare controlled-release micron-sized particles, we designed nanocomposite coating agents with the intention to form a core-shell structure composed of two types of acrylic polymers with different glass transition temperatures (Tg) and evaluated their coating performance. A series of nanocomposite acrylic latexes synthesized by emulsion polymerization was freeze-dried after salting-out to create the powder form. An ion-exchange resin loaded with diclofenac sodium (DS, a model drug) (IER-DS) with a median diameter of approximately 100 µm was used as the core particle. Dry coating of the IER-DS with nanocomposite coating agents was carried out using a laboratory-made coating apparatus assisted with mild-intensity vibration and zirconia bead impaction. The coated particles were cured by heating at a temperature 20 °C higher than the Tg for 12 h to complete the film-forming process. It was found that the highest coating efficiency (more than 70%) and a remarkably prolonged release period of the drug (the time required for 50% release reached approximately 12 h) could be achieved when nanocomposite coating agents with a soft polymeric core (Tg = 30 °C) and a hard polymeric shell (Tg = 80 °C) were applied. In contrast, nanocomposite coating agents with a combination of a hard polymeric core and a soft polymeric shell resulted in lower coating efficiency. These results demonstrate that nanocomposite polymeric coating agents composed of a soft core and hard shell are effective for the production of drug-loaded microparticles with a prolonged release function by a binder-free dry-coating process.

Dry fabrication of poly(dl-lactide-co-glycolide) microspheres incorporating a medium molecular drug by a ball mill method

Poly(dl-lactide-co-glycolide) acid (PLGA) microspheres is a useful carrier for controlled drug release. However, the organic solvents used in their conventional manufacturing process may affect the chemical structure of a macromolecular drug. Thus, we investigated the applicability of a dry fabrication method for PLGA microspheres. Cyanocobalamin (MW = 1,355) (VB₁₂) was used as a model drug, and it formed agglomerates under mild conditions with powdered PLGA in a generic ball milling system. Light and scanning electron microscopy showed the formation of PLGA microspheres and few agglomerates. The obtained microspheres had the particle size injectable as suspensions, namely smaller than 150 μm specified for subcutaneous and intramuscular injections by the Japanese Pharmacopoeia. The observed and theoretical drug contents were consistent. PLGA microspheres fabricated using a combination of small (ϕ3 mm) and large (ϕ10 mm) balls showed low initial burst of cyanocobalamin release in vitro. The in vitro drug release profile was equivalent with that of the microspheres fabricated by a conventional oil-in-water emulsion solvent evaporation method, while the drug release profile was influenced by the brand of the PLGA used. To prevent drug loss during fabrication, the dry fabrication method using a ball mill should be applied to prepare PLGA microspheres containing a medium macromolecular drug.

On-demand fully customizable drug tablets via 3D printing technology for personalized medicine

Personalized medicine should ideally be prescribed to every individual because of the unique characteristics (e.g., biological, physical, and medical) of each individual. It is, however, challenging to provide personalized medicine for the mass population of specific individuals effectively and efficiently. This manuscript describes a method of fabricating fully customizable drug tablets for personalized medicine by the 3D printing technology. This method involves the versatile fabrication of the tablets via the specifically designed 3D printed molds of different shapes and sizes, and an intuitive 1-dimensional release of drug that relates the shape of the drug-containing matrix to the release profile. The customization includes all the aspects of varying dosage, duration, release profiles, and combination of multiple drugs. In particular, it has previously been technically difficult to devise a single platform that fabricates carriers that release drug with any desired type of release profiles. This method of fabricating fully customizable tablets is simple, inexpensive, and efficient. Detailed selection and investigation of the materials ensured that the tablet and the method of fabrication are safe (e.g., biocompatible, FDA-approved ingredients used) and other desirable features (e.g., sustained release and high dosage) are achieved. These desirable characteristics of the method thus allow fully customizable drug tablets to be fabricated efficiently on the spot after the diagnosis of individual patients; at the same time, the method can be made widely accessible to the mass population. Hence, the concept of personalized medicine can truly be realized.

Microparticles for sustained release of water-soluble drug based on a containment, dry coating technology

Controlled release microparticles in a sub-gram-scale batch were fabricated using a ball mill, dry coating technique, to coat the water-soluble core material. This process also guaranteed the maintenance of the containment's integrity during the dry coating process. Quinine (average diameter, ca. 10 μm) and carnauba wax were used as the core and coating material, respectively. We evaluated the influence of process time, milling speed, and quinine-to-carnauba wax ratio on the particle size of the coated particles and their in vitro drug release profiles. Scanning electron microscopic observations suggested that the small wax particles attached to the core (quinine) particles resulted in a smooth film during the dry coating process. The size distribution of the coated particles agreed with the theoretically estimated size distribution. The in vitro release test demonstrated that the coated particles released quinine over 2 h in a biphasic mode. These results suggest that dry coating of microparticles less than 50 µm (D99) is feasible on a several-grams-batch scale. This new ball mill-coating technique also enables a guaranteed containment, a prerequisite for the manufacturing of highly bioactive or biohazard substances.

Surface modification of acetaminophen particles by atomic layer deposition

Active pharmaceutical ingredients (APIs) are predominantly organic solid powders. Due to their bulk properties many APIs require processing to improve pharmaceutical formulation and manufacturing in the preparation for various drug dosage forms. Improved powder flow and protection of the APIs are often anticipated characteristics in pharmaceutical manufacturing. In this work, we have modified acetaminophen particles with atomic layer deposition (ALD) by conformal nanometer scale coatings in a one-step coating process. According to the results, ALD, utilizing common chemistries for Al₂O₃, TiO₂ and ZnO, is shown to be a promising coating method for solid pharmaceutical powders. Acetaminophen does not undergo degradation during the ALD coating process and maintains its stable polymorphic structure. Acetaminophen with nanometer scale ALD coatings shows slowed drug release. ALD TiO₂ coated acetaminophen particles show cytocompatibility whereas those coated with thicker ZnO coatings exhibit the most cytotoxicity among the ALD materials under study when assessed in vitro by their effect on intestinal Caco-2 cells.