The reduction of the particle size of felodipine is a good way to improve the application of particles with low water solubility and technical problems. There are various benefits and a good method of dissolution, but there is the possibility of disorder induction and solid state modification. Sahu and Das prepared felodipine suspensions by separate precipitation and combined with ultrasonic treatment with ethanol as solvent and water as antisolvent. According to their results, felodipine suspension can increase the dissolution rate and improve its oral bioavailability. Their research results showed that the dissolution profile of the suspension showed that the release rate was as high as 79.67% within 4 hours. The author also explained that the ultrasonic precipitation method is a method to prepare a uniform and stable felodipine suspension. Such as low water solubility, increased bioavailability, and absorption rate, a delivery system with high payload, prolonged circulation time and active targeting ability, and has protective effects and blood flow effects. For decades, scientists have been using microparticles for their toxicity and side effects. Despite the various developments mentioned above, the particles also have some disadvantages. It has only recently been realized that these carrier systems themselves may be risky to patients.

The reduction of particle size will also make the particle fluidity and wettability worse, and the electrostatic force will be strengthened, which will lead to problematic formulations. In addition, damage to the nervous system and respiratory system, circulatory system problems, and particle toxicity are also used in particle applications. Therefore, the reduction of particle size and the development of particle utilization methods must be monitored.

Because the design and development of new drug entities are complex, time-consuming, and require high costs. Therefore, improving the traditional solubility may be a suitable idea to increase the bioavailability of poorly water-soluble. Chemicals exist in the form of particles, crystals or suspensions, without complex synthesis process, as a simple method to improve the dissolution rate, to improve the bioavailability of. The use of these systems has led to an increase in dissolution rate and thus increased bioavailability after oral administration. In these systems, the preparation of crystals is a simple, effective and promising oral delivery method with poor water solubility, because these are only composed of crystal forms and ranges. The spray drying method has become a common method for structural solidification. Its low cost makes this method popular in the industry. In addition to greater bioavailability, particles can also provide smaller doses, thereby reducing toxicity and dose variability. Due to some shortcomings of the particles, it is necessary to monitor the manufacturing process of the structure.