The Consistency Evaluation of Generic Drugs Requires Attention to the Particle Size of API

In the development of pharmaceutical preparations, due to the different synthesis processes of API from different sources, there may be differences in their solubility, crystal form, particle size, and impurities, which may affect the consistency of the product. In the evaluation of the consistency of generic drugs, the particle size control of API should not be underestimated.

In the production of APIs, particle size is an indispensable indicator. According to the dissolution requirements of different tablets, the particle size of the bulk drug should be controlled in different particle sizes to maximize the efficacy. The particle size distribution of the API may have a significant impact on the properties of the final product such as solubility, bioavailability, content uniformity and stability. In addition, the particle size distribution of API and excipients will also affect the flowability, total mixing uniformity, compressibility and other manufacturability of the drug, which may affect the safety, effectiveness and quality of the drug in the future.

For drugs that belong to BCS classification II and have high permeability and low solubility, solubility has a greater impact on absorption in the body, and the impact of particle size on product quality must be investigated. If the particle size of different batches is different, it will have a direct impact on the efficacy and safety of the drug. Therefore, it is necessary to pay close attention to this point in the consistency evaluation of the drug. For example, in order to improve the in vitro dissolution rate of nifedipine tablets, researchers have separately investigated the influence of drug particle size, diluent, and disintegrant on the in vitro dissolution rate, and compared the dissolution characteristic curve to screen the prescription [1]. The results of the study found that the nifedipine tablets prepared with the optimal prescription dissolve well, reaching the 2000 edition of the Chinese Pharmacopoeia. Finally, the formulation of the tablet is reasonable, the preparation process is simple and feasible, and it is suitable for industrial production.

Carrying out the consistency evaluation of generic drugs can bring the quality and efficacy of generic drugs to the same level as the original drugs, which will not only help save medical costs, but also improve the quality of generic drugs and ensure the safety and effectiveness of the public’s medication. Medicilon Biopharmaceuticals has rich experience in the quality consistency evaluation of generic drugs. Medicilon’s comprehensive service platform for quality consistency evaluation of generic drugs can provide a comprehensive comparison of the quality of reference preparations and generic drugs, and the prescription process can be performed twice. Development services and animal BE services, etc.

Azithromycin belongs to BCS classification 2 or 4 drugs, and its solubility is poor, and the particle size of the API has a greater impact on the in vitro and in vivo properties of the drug. The establishment of a method for determining the particle size and particle size distribution of azithromycin APIs will help to achieve effective control of the particle size of azithromycin APIs, speed up the process of consistency evaluation, and reduce the risk of drug consistency evaluation. For example, researchers have conducted optimization of the crystallization process to improve the particle size of azithromycin API [2]. Studies have found that the particle size of azithromycin API directly affects the production efficiency and product quality of azithromycin preparations (capsules, tablets, etc.). Researchers explored the effects of crystallization temperature, drying temperature, crystal growth time, etc. on the particle size of azithromycin API in the experiment. The experimental results show that the best process conditions: the crystallization temperature is 40°C, the crystal growth time is 120 min, and the drying temperature is 60°C; by optimizing the crystallization process, such as changing the crystallization temperature, changing the drying temperature, extending the crystal growth time, etc. It can improve the particle size of azithromycin API and improve the production efficiency and product quality of azithromycin preparations.

The particle size of the drug substance can be controlled by controlling the parameters of the drug pulverization, and then the particle size can be measured by using a dry particle size analyzer or a wet laser particle size analyzer to control the particle size range. The particle size of APIs of II, II, and IV have a great impact on consistency evaluation. At present, foreign pharmaceutical preparations can accurately control the particle size range of API. However, many domestic formulation factories control API particle size through mechanical pulverization, and rarely use synthetic crystallization. Process control, foreign countries control a little more through synthesis process.

[1] Study on the in vitro dissolution characteristics of nifedipine tablets [J].

[2] Optimizing the crystallization process to improve the particle size of Azithromycin API [J].

Related Articles:

Steps in Generic Drug Development