The delayed TPm crystal growth seen in the CARS dissolution imaging (Fig. 8) was expected to affect the TPa dissolution rate and Fig. 9 shows that this was the case. Fig. 9 shows the dissolution profiles for TPa and TPm compacts undergoing dissolution using MC solution as the dissolution medium. From Fig. 9 it can be seen that the

characteristic decrease in dissolution rate associated with TPm growth on the surface of TPa compacts (Fig. 7) is no longer seen. Instead the TPa compacts reach a concentration of about 150 μg/mL and remain there for the duration of the experiment. The dissolution behavior of the TPm compacts appear minimally affected by the use of the MC dissolution medium as

they reach a concentration of about 80 μg/mL and remain there for the duration of the experiment. This concentration is the same Gefitinib manufacturer as was observed for water without the polymer, revealing that the solubility of the drug is not affected by the polymer in solution, and therefore the different dissolution profiles obtained with and without polymer solution are not solubility mediated. The steady-state intrinsic dissolution rates were calculated to be 700 ± 130 μg/min/cm2 and 350 ± 40 μg/min/cm2 for the compacts prepared from TPa and TPm respectively (assuming both compacts had a perfectly planar surface). Since the solubility of the TPa is twice that of TPm in water at 25 °C [29], a two-fold increase in the dissolution rate of the compact prepared from TPa would theoretically only be expected if there were http://www.selleckchem.com/products/abt-199.html no conversion to the monohydrate. However, an increase in surface area of the compacts prepared from TPa after TPm formation was observed in water which affected the dissolution behavior, and therefore a surface area increase can also be expected to affect those the dissolution profiles

in the polymer solution. Additionally, from Fig. 9 there are noticeable fluctuations in the steady-state concentrations (when compared to Fig. 7) of both TPa and TPm this is attributed to bubbles in the dissolution medium not removed by sonication. The inherent confocality, chemical specificity, and speed provided by CARS microscopy increases the spatial and chemical resolution of the system providing advantages over existing approaches including traditional optical microscopy and Raman microscopy based on spontaneous Raman scattering. The biggest advantage when compared to traditional optical microscopy is the fact that the detected signal is generated when the excitation beams match the Raman vibrational mode for the chemical of interest this provides chemical selectivity. If the excitation laser frequencies are incorrect or the sample is the wrong chemical then no resonant signal is generated.