Transdermal Delivery of Salmon Calcitonin Using a Dissolving Microneedle Array: Characterization, Stability, and In vivo Pharmacodynamics
AAPS PHARMSCITECH
Authors: Zhang, Lu; Li, Yingying; Wei, Fang; Liu, Hang; Wang, Yushuai; Zhao, Weiman; Dong, Zhiyong; Ma, Tao; Wang, Qingqing
Abstract
Salmon calcitonin (sCT) is a polypeptide drug, possessing the ability to inhibit osteoclast-mediated bone resorption. Just like other bioactive macromolecules, sCT is generally administered to the patients by either injection for poor compliance or through nasal spray for low bioavailability, which limits its use as therapeutic drugs. In the present study, to overcome the limitations of the conventional routes, two new dissolving microneedle arrays (DMNAs) based on transdermal sCT delivery systems were developed, namely sCT-DMNA-1 (sCT/Dex/K90E) and sCT-DMNA-2 (sCT/Dex-Tre/K90E) with the same dimension, meeting the requirements of suitable mechanical properties. An accurate and reliable method was established to determine the needle drug loading proportion in sCT-DMNAs. The stability study exhibited that the addition of trehalose could improve the stability of sCT in DMNA under high temperature and humidity. Further, in vivo pharmacodynamic study revealed that DMNA patch could significantly enhanced relative bioavailability to approximately 70%, and the addition of trehalose was found to be beneficial for sCT transdermal delivery. Therefore, sCT-DMNA is expected to replace traditional dosage form, providing a secure, efficient, and low-pain therapeutic strategy for bone disorders.
A conceptual framework for ex ante valuation of ecosystem services of brownfield greening from a systematic perspective
ECOSYSTEM HEALTH AND SUSTAINABILITY
Authors: Zhong, Qicheng; Zhang, Lang; Zhu, Yi; Konijnendijk van den Bosch, Cecil; Han, Jigang; Zhang, Guilian; Li, Yuezhong
Abstract
Introduction: Although Brownfield greening (BG) can be a crucial solution to green space deficiency in dense urban areas, the potential benefits of different BG initiatives have rarely been quantitatively pre-evaluated. Here, the concept and main features of BG and its costs and benefits are firstly depicted. Next, a conceptual framework is presented which combines ecosystem service (ESS) valuation, economic cost-benefit analysis, and spatial pattern analysis. The framework is used to perform ex ante valuation of the ESS value of BG in Xuhui District, Shanghai. Outcomes: The scenario comparison results show that it can spatially reflect a closer-to-reality value of ESS at the urban scale instead of a theoretical value at the site scale. The ultimate values of ESS (After economic and landscape adjustments) in the composite scenario is more than 21% higher than those in the full-eco scenario, whereas the initial values of ESS (before the adjustments) in the former was 14% lower than those in the latter. These results suggest that a considerable part of brownfield greening projects need to be implemented in the more populated and economically vibrant areas instead of solely in the ecological construction zone, thereby correspondingly providing more cultural and regulation services and forming a better urban green space network. Conclusion: The framework provides a simple, science-based, and feasible tool for making BG decisions from a systematic perspective in dense urban areas. It can help meet the need for applying ESS knowledge to BG-based green space planning and policy making in the context of urban sustainable development.