The Spray Drying Method of Solid Dispersant Preparation Technology

In the field of drug research, drug candidates are not easily soluble in water, which is one of the challenges that modern drug formulation researchers often face. Due to the low solubility and low bioavailability of this drug, the application of solid dispersion technology can improve the properties of drug compounds that are difficult to dissolve in water, and improve the dissolution rate and bioavailability of the drug. Solid dispersion refers to a dispersion system formed by uniformly dispersing drugs in a certain solid carrier material in molecular, amorphous, and microcrystalline states. Spray drying is a relatively common technique for preparing solid dispersions.

The spray drying method means that the drug and the carrier are dissolved in a solvent and atomized into a dry gas. After the solvent evaporates, dry particles are formed. It is a method that can produce solid products from a liquid in the form of a solution or suspension, and its application is greatly improved the bioavailability of poorly soluble compounds.

The liquid enters the nozzle to be atomized, and the generated droplets are mixed with the dry gas, the solvent in it evaporates, and finally the particles are separated from the dry gas. Spray drying is a very fast drying process because it generates fine droplets and has a high specific surface area. There are different devices for spray drying. Although the atomizing device and atomizing force are not the same, most of the components are similar. For the preparation of solid dispersions, the polymer and the poorly soluble drug are generally dissolved in a suitable solvent, and then spray-dried to make the drug highly dispersed in the polymer in an amorphous state. Medicilon not only has outstanding performance in the development and research of traditional dosage forms, but also has a professional technology platform for insoluble innovative drugs and a professional high-end formulation technology platform, such as inhalation, ophthalmic, transdermal platforms for slow and controlled release drug delivery and new particle system drug delivery. The R&D team of Medicilon’s preparation department has a strong professional level and rich experience in preparation process research and analysis to ensure standardized, high-quality and efficient completion of preparation process research and quality research, and establish corresponding process control indicators. Finally realize the industrialized production of products.

The principle of spray drying technology:

Spray drying technology dries liquid materials into powder, and the drying process can be divided into 3 stages:

(1) Use an atomizer to atomize the liquid to form many small droplets;

The feed solution and atomizing gas are respectively fed into an atomizing device (rotary, pneumatic, hydraulic or ultrasonic), and then the liquid stream is atomized at the tip of the nozzle to form liquid filaments and finally into fine droplets. The atomizer is the core device in the spray drying process, and its function is to disperse the liquid into fine droplets.

(2) When the droplets are in direct contact with the dry hot air, the solvent evaporates quickly to form dry particles;

After the droplets are formed, they enter the dryer and come into direct contact with hot air. The droplets in the drying chamber are in contact with the drying gas at a certain temperature, and the solvent components in the droplets evaporate until a solid product is formed.

(3) Separation and collection of dry particles.

Finally, the dried particles are separated from the drying gas in a separator and collected in a receiving container. Commonly used devices for collecting dried products in spray drying technology include cyclone separators and bag filters.

In the modern pharmaceutical industry, the use of spray drying to prepare solid dispersions provides an effective solution to the oral bioavailability of poorly soluble drugs. The spray drying method can produce micron or even nanometer-level solid dispersion powder, which is an effective technology to improve the solubility of poorly soluble drugs, and is especially suitable for heat-sensitive drugs.

The spray drying method has the advantages of rapid, economical, one-step molding treatment, suitable for particle engineering and thermally unstable materials, and continuous production. The disadvantage is that depending on the type of solvent, a relatively high temperature may be used for drying, and in order to ensure uniform and effective drying of the spray, the concentration of the solution is usually required to be relatively small, so a large amount of organic solvent needs to be consumed, which will significantly increase the process cost and Equipment cost, etc. However, with the advancement of science and technology, the technical problems of spray drying technology in the pharmaceutical industry will be gradually solved, and there will be a wider application prospect.

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