XCT research case study: timelapse of hydration of solid injectable dispersions

This project aims to produce long-acting subdermal injectable depots for the prevention and treatment of HIV.

Treatment of HIV is currently accomplished by daily oral dosing, using a combination of antiretroviral drugs. The major drawback with this system is the dependence on the patient to consistently take regular doses, maintaining a circulating concentration of drug and therefore maintaining the treatment efficacy. Long-acting medicines allow for months of protection from a single administration, reducing the adherence demands on the patient. This leads to improved therapeutic outcomes and improves the patient quality of life.

Figure 1: Volume rendering of an X-ray CT scan of the whole injectable device, and a sub-section scanned at higher resolution (3 microns) for the time-lapse experiment. 

The devices discussed here are manufactured using a solid drug loaded core where the drug is dispersed within a polymeric matrix. The core is then coated using an insoluble polymer to control the rate of diffusion of the drug.

X-ray microcomputed tomography has enabled visualisation of structural changes within the implants in aqueous media, revealing changes in both the core and coating. Helping to understand both the mechanism of drug release as well as the impact of defects.

 

Figure 2: Volume rendering of a section of the injectable while it is undergoing hydration over a two-week period. Solid material is shown in white, pores in blue.

 

For more information about this project, contact: Sam Galbraith

 

Images and videos shown here were created with Drishti from Zeiss Xradia Versa data.