Mechanical particle coating using polymethacrylate nanoparticle agglomerates for the preparation of controlled release fine particles: The relationship between coating performance and the characteristics of various polymethacrylates

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.

Intelligent control of nanoparticle synthesis through machine learning

The synthesis of nanoparticles is affected by many reaction conditions, and their properties are usually determined by factors such as their size, shape and surface chemistry. In order for the synthesized nanoparticles to have functions suitable for different fields (for example, optics, electronics, sensor applications and so on), precise control of their properties is essential. However, with the current technology of preparing nanoparticles on a microreactor, it is time-consuming and laborious to achieve precise synthesis. In order to improve the efficiency of synthesizing nanoparticles with the expected functionality, the application of machine learning-assisted synthesis is an intelligent choice. In this article, we mainly introduce the typical methods of preparing nanoparticles on microreactors, and explain the principles and procedures of machine learning, as well as the main ways of obtaining data sets. We have studied three types of representative nanoparticle preparation methods assisted by machine learning. Finally, the current problems in machine learning-assisted nanoparticle synthesis and future development prospects are discussed.

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.

Design of taste-masked swellable drug particles using dry-coating technology with mechanical curing

A novel dry coating technique for fine particles that does not require any liquids has been developed. Swellable ordered-mixed drug particles (Swell-OM-spheres, SOS), using a modified starch as the core particle and a drug coating layer have been previously developed. In the present work, SOS particles were further processed to generate 100-μm taste-masking particles using an all dry coating processes. SOS particles were coated with a gastric-soluble powder using a mechanical powder processor. The coated particles (CPs) were subsequently heated while rotating in the same powder processor, completing film formation by a process termed dynamic curing. As a control, conventional film formation (static curing) was performed using a drying oven. The CPs obtained by these two curing processes had distinct appearances, but exhibited equivalent dissolution suppression effects in a medium at pH 6.8 (the pH of the oral cavity). The suppression effect was further improved by adding a plasticizer to the coating powder, even though a lower heating temperature was required. Orally disintegrating tablets incorporating these CPs exhibited excellent taste-masking performance, i.e., suppressing taste in saliva while accelerating dissolution in gastric juice. The dissolution behavior indicated that the CPs can provide an ON/OFF switching function in drug release.

Binder-free dry particulate coating process using a mild vibration field: Effects of glass-transition temperature and powdering method of polymeric coating agents on coating performance

We employed a new dry coating process with mild-intensity vibration to prepare a 100-µm-sized microparticle capable of prolonged release of a drug. To accomplish this without using a binder, a series of laboratory-made acrylic latexes with different glass transition temperatures (Tg) ranging from 30 °C to 80 °C were employed as coating agents, and the effects of Tg and powdering method of the coating agents on coating performance were investigated. The laboratory-made acrylic latexes were powdered by spray-drying (SD) or freeze-drying (FD). Diclofenac sodium (DS)-loaded ion-exchange-resin with particle size ∼100 µm was used as a core particle. The process utilized vibrations with amplitude of 0.5 mm and frequency of 90 Hz to form an ordered mixture composed of the core particles with the loosely-layered coating agents. Subsequently, the coating agents were fixed mechanically on the core particle by impaction of zirconia beads. The coating agents powdered by FD showed higher coating efficiencies than those powdered by SD, irrespective of the differences in Tg values. Among the coating agents powdered by FD, the particles coated at Tg = 60 °C exhibited the most prolonged drug-release, although the coating efficiency was not the highest. In our proposed process utilizing mild vibration, we demonstrated that adjusting the Tg of the coating agents is crucial to the formation of binder-free multiple coating layers for prolonged drug release.