Today, we shadowed a few scientists at in vitro release testing (IVRT). To start off, Craig, the head of the IVRT team, talked us through some of the experiments performed and methods used by IVRT, including different dosing techniques and strengths of drugs and how they impact the release rates. Then, Akeem demonstrated a test using vertical diffusion cells. The setup was similar to what we saw yesterday, simulated the properties of skin with a synthetic membrane rather than using actual skin, requiring a smaller time frame for each experiment. In order to determine the release medium that would result in an optimal dose-release ratio, Akeem tested two different solutions: a 50:50 mixture of water and methanol and a 70:30 ratio of water and ethanol. Rather than applying the cream with a pipet as the scientists in IVPT did, he added a constant volume of the drug to each cell by filling the hole in a washer-shaped wafer placed on top of the membrane.
After lunch, we talked with Meredith, who explained some of the functions of HPLC machines and what she looks for on the chromatographs. Then, Ms. Allen paid us a visit, and we discussed our experiences over the past two weeks. Finally, we met with Craig again; he discussed some more of the FDA regulations and guidelines that have to be followed when testing new proposed drugs, as well as the different types of tests performed on the drugs, some of which can take years to complete.
