Use of thermoanalytical methods in quantification of drug load in mesoporous silicon microparticles

Evaluation of Mesoporous TCPSi, MCM-41, SBA-15, and TUD-1 Materials as API Carriers for Oral Drug Delivery

“…The washing removed the detected crystalline portion of ibuprofen, which was certified by the absence of the ibuprofen peaks in the XRD patterns of washed samples (Figure 5c for MCM-41-ibu). However, a fraction of crystalline ibuprofen was found in the sample TCPSi-ibu, despite the washing of the sample at the filtration step (Lehto et al 2005). The presence or absence of crystalline drug also was confirmed by DSC analysis using the melting peak of ibuprofen in the thermograms as an indication of crystalline phase of drug present in the sample.…”

“…In reality the total drug concentration of a loaded mesoporous sample consists of the drug in the mesopores as well as possible drug content on the particle surfaces and even residue-free bulk drug from the loading solution. The detection of crystalline ibuprofen in a loaded-mesoporous solid is associated with a particle surface adsorbed drug portion in the sample (Charnay et al 2004;Lehto et al 2005;Salonen et al 2005a;Salonen et al 2005b). This was illustrated by the results of the present sample characterizations, where all the samples loaded with the high concentration solution exhibited a crystalline drug phase, i.e., portion of drug loaded on the host particle surfaces.…”

“…The HPLC and TG results of the total ibuprofen loads were in good correlation. After the total API content of a sample was determined (mean value of the HPLC and TG results used), the surface loaded portion of the total amount was quantified using DSC, according to the procedure introduced in previous studies (Lehto et al 2005;Salonen et al 2005a;Salonen et al 2005b). According to the procedure, the enthalpy of the melting endotherm of ibuprofen was used to calculate the amount of drug on the mesoporous silica/silicon particle surfaces.…”

“…We recently have introduced a method based on differential scanning calorimetry, whereby the drug component residing on the drug host particle surfaces can be readily distinguished and quantified. In combination with, for example, thermal gravimetry and/or liquid chromatography data of the total API content, a reliable quantification of the true mesopore drug loads of samples is achieved (Lehto et al 2005;Salonen et al 2005a;Salonen et al 2005b).…”

Implication of Water Molecules at the Silica–Ibuprofen Interface in Silica-Based Drug Delivery Systems Obtained through Incipient Wetness Impregnation

“…22 Recent literature showed that drugs confined in porous matrices are submitted to a confinement effect that influences their physical state at room temperature 23,24,25,26,27 . It is generally admitted that the exacerbated mobility evidenced in the case of encapsulated ibuprofen influences strongly the release profile observed in vitro.…”