In modern formulation research, the preparation of poorly soluble compounds in aqueous media is a difficult problem, and poorly soluble drugs can lead to low drug bioavailability. Solid dispersion is a common method to solve the solubility of poorly soluble drugs, and spray drying is a common technique for preparing solid dispersions.
At the beginning of the 19th century, La Mont proposed spray drying equipment. With the maturity of spray drying technology and the continuous updating of equipment, its application range has become wider and wider. It has a very wide range of applications in both the food industry and the pharmaceutical and chemical industries. Application prospects. In the pharmaceutical field, spray drying is a common method of drying preparations, initially as a drying technology to process liquids into powder products. It is widely used and has good effects, and its unique advantages bring opportunities for the development of new pharmaceutical preparations.
The principle of spray drying technology
The spray drying technology dries liquid materials into powder. The drying process can be divided into 3 stages : The atomizer is the core device in the spray drying process. The atomizer is used to atomize the liquid to form many fine mists. After the droplets are formed, they enter the dryer and directly contact with the dry hot air. The solvent quickly evaporates to form dry particles. The difference between the vapor pressure of the solvent in the liquid and the vapor pressure in the gas phase causes the solvent in the mist to evaporate, and the solute is precipitated to form particles. The separation and collection of dry particles. The commonly used devices for collecting dry products in spray drying technology include cyclone separators and bag filters.
Spray drying has many advantages: its drying efficiency is high, and the time required for spray drying is short, only 3~5 seconds. It can be operated continuously, and the production capacity per hour can be as small as a few milligrams or as large as hundreds of tons, which is suitable for large-scale industrial production.
The preparation of solid dispersion helps to improve the bioavailability of the compound, and solid dispersion is an extremely promising solubilization technology. Preparation of poorly soluble drugs and polymer raw materials into solid dispersions by hot melt extrusion and spray drying techniques can significantly improve the solubility and dissolution rate of poorly soluble drugs, thereby increasing the bioavailability. Medicilon’s preparation department uses unique technologies to solve the solubility and permeability of drugs, improve the success rate of drug development, shorten the development time, and promote compounds to become truly valuable new drugs. Technical platforms for solid dispersion (such as hot melt extrusion, etc.), micronization, solubilization, inclusion compounds, in vitro dissolution/in vivo PK comprehensive evaluation, etc. have been established and improved.
The spray drying method is a method suitable for industrial scale-up and has been successfully used for preparing solid dispersions in marketed products. In order to compare the solubility, in vitro dissolution rate and drug existence state of ibuprofen solid dispersion prepared by hot melt extrusion method and spray drying method. Some researchers use pyrrolidone (PVP K30) as the carrier, and the mass ratio of the drug carrier is 13. The solid dispersion of ibuprofen was prepared by hot melt extrusion and spray drying, and they were measured and compared in 0.1 mol·L-1 hydrochloric acid. The dissolution difference; Differential scanning calorimetry experiment (DSC) and X-ray diffraction experiment (XRD) were used to identify the solid dispersion of ibuprofen. The results of this study found that compared to the hot melt extrusion method, the ibuprofen-PVP K30 solid dispersion prepared by the spray drying method can significantly improve the solubility and dissolution of the drug, and the ibuprofen can be nearly complete within 30 minutes freed.
In short, 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.
 Application of spray drying technology in the design and production of new formulations [J].
 Comparison of the preparation of solid dispersions of ibuprofen by hot melt extrusion method and spray drying method [J].