To study the characteristics of nasal airflow in the presence of nasal cycle by computational fluid dynamics. CT scan data of a healthy Chinese individual was used to construct a three-dimensional model of the nasal cavity to be used as simulation domain. A sinusoidal airflow velocity is set at the nasal cavity entrance to reproduce the breathing pattern of a healthy human. There was a significant difference in the cross-sectional area between the two sides of the nasal cavity. Particularly, the decongested side is characterized by a larger cross-section area, and consequently, by a larger volume with respect to the congested side. The airflow velocity, pressure, and nasal resistance were higher on the congested narrow side. The temperature regulation ability on the congested narrow side was stronger than that on the decongested wider side. During the nasal cycle, there are differences in the nasal cavity function between the congested and decongested sides. Therefore, when evaluating the impact of various factors on nasal cavity function, the nasal cycle should be considered.

Background/Objectives: Numerical simulation plays an important role in pharmaceutical preparation recently. Mechanistic models, as a type of numerical model, are widely used in the study of pharmaceutical preparations. Mechanistic models are based on a priori knowledge, i.e., laws of physics, chemistry, and biology. However, due to interdisciplinary reasons, pharmacy researchers have greater difficulties in using computer models. Methods: In this paper, we highlight the application scenarios and examples of mechanistic modelling in pharmacy research and provide a reference for drug researchers to get started. Results: By establishing a suitable model and inputting preparation parameters, researchers can analyze the drug preparation process. Therefore, mechanistic models are effective tools to optimize the preparation parameters and predict potential quality problems of the product. With product quality parameters as the ultimate goal, the experiment design is optimized by mechanistic models. This process emphasizes the concept of quality by design. Conclusions: The use of numerical simulation saves experimental cost and time, and speeds up the experimental process. In pharmacy experiments, part of the physical information and the change processes are difficult to obtain, such as the mechanical phenomena during tablet compression and the airflow details in the nasal cavity. Therefore, it is necessary to predict the information and guide the formulation with the help of mechanistic models.

Background: Kai Hou Jian has an outstanding therapeutic effect and clinical use against pharyngeal infection for many years, while a few studies reported it also had an effect in laryngitis. This study aimed to evaluate the efficacy and safety of short-course oral inhalation of traditional Chinese medicine Kai Hou Jian in adults with acute laryngitis. Methods: A total of 86 patients with acute laryngitis who met the inclusion criteria were randomly assigned according to the random number table method into a Kai Hou Jian treatment group or a budesonide control group. Patients received 2.5 mL of Kai Hou Jian via transoral atomization twice daily for 1 week, while the control group received budesonide nebulization (1 mg, bid) for 1 week. The change of symptoms scores of acute laryngitis and laryngoscopy scores before and after treatment were performed to value the effect of Kai Hou Jian and the safety was assessed by the patient's discomfort and the incidence and self-reported adverse events during treatment. Results: The symptoms of acute laryngitis were significantly reduced in patients treated with Kai Hou Jian on day-3. Forty-two patients from the Kai Hou Jian and 40 patients from budesonide treated groups both experienced notable clinical improvement after 1 week. There was no difference in the two groups at the baseline. For individual symptoms, Kai Hou Jian could significantly improve sore throat [95% confidence interval (CI): –1.81 to –0.14, P=0.03], while budesonide yielded better improvement in hoarseness (95% CI: 0.67 to 0.20, P=0.001). For laryngoscopic parameters, the scores of laryngeal mucosa were significantly decreased in both groups from baseline, and there were no statistical differences in vocal cord hyperemia, edema, sputum congestion, edema, mucus adhesion, or epiglottic congestion between the groups after 1 week. We also found that the treatment of Kai Hou Jian nebulization could reduce the extent or range of vocal cord leukoplakia after 1 week. Conclusions: The short-course treatment of Kai Hou Jian atomization had significant effect in improving adult acute laryngitis and it was also possibly exhibiting a positive effect on vocal cord leukoplakia. Trial Registration: Chinese Clinical Trial Registry identifier: ChiCTR1900026660.