Establishment and Validation of a Transdermal Drug Delivery System for the Anti-Depressant Drug Citalopram Hydrobromide.

To enhance the bioavailability and antihypertensive effect of the anti-depressant drug citalopram hydrobromide (CTH) we developed a sustained-release transdermal delivery system containing CTH. A transdermal diffusion meter was first used to determine the optimal formulation of the CTH transdermal drug delivery system (TDDS). Then, based on the determined formulation, a sustained-release patch was prepared; its physical characteristics, including quality, stickiness, and appearance, were evaluated, and its pharmacokinetics and irritation to the skin were evaluated by applying it to rabbits and rats. The optimal formulation of the CTH TDDS was 49.2% hydroxypropyl methyl cellulose K100M, 32.8% polyvinylpyrrolidone K30, 16% oleic acid-azone, and 2% polyacrylic acid resin II. The system continuously released an effective dose of CTH for 24 h and significantly enhanced its bioavailability, with a higher area under the curve, good stability, and no skin irritation. The developed CTH TDDS possessed a sustained-release effect and good characteristics and pharmacokinetics; therefore, it has the potential for clinical application as an antidepressant.

[Effects of straw returning to movement characteristics of soil preferential flow in sugarcane fields]. / ç§¸ç§†è¿˜ç”°å¯¹ç”˜è”—åœ°åœŸå£¤ä¼˜å ˆæµè¿åŠ¨ç‰¹å¾çš„å½±å“.

The measures of returning straw to the field can change soil environment in the field and affect crop growth. In order to explore the impacts of different straw returning measures on the preferential flow in the field, we investigated the movement characteristics of preferential flow in sugarcane fields under different straw returning measures [straw mulching (CM), straw burning mulching (BM), and non-straw mulching (CK)] in Guangxi by combining image analysis techniques with ecological landscape pattern analysis methods. The results showed that under the same external water supply environment, soil staining morphology of non-straw mulching sugarcane fields differentiated into finger-like and clump-like. Both straw mulching and straw burning mulching were mainly differentiated into clump-like. The mean total staining area ratio was significantly higher than that of non-straw mulching (26.0%). The ratio of surface staining area decreased rapidly under non-straw mulching. The water movement range decreased rapidly under straw mulching and straw burning mulching in the depth of 15-30 cm. The change rate of straw mulching staining area ratio was the lowest in the deep soil. The shape index of non-straw mulching was 15.54. The water flow movement was more concentrated. The average sub-circular index of straw mulching and straw burning mulching was 0.67 in the sugarcane field, with a higher degree of preferential flow bending, an average proximity index of 0.87, and better water flow connectivity. The average substrate flow depth (3.52 cm) and edge density index (11.51) were the smallest under non-straw mulching, but the priority flow ratio was the largest (73.2%), and the spatial development degree of preferential flow was the highest. The straw returning measures reduced the preferential flow in the sugarcane fields, with positive effects on water conservation.