Biomedical subjects

F Verpoort

Publications and source records attributed to F Verpoort.

4 recordsLinked to original sources

PubMed2006

Influence of particle size on the quantitative determination of salicylic acid in a pharmaceutical ointment using FT-Raman spectroscopy.

A second order polynomial calibration model was developed and statistically validated for the direct and non-destructive quantitative analysis - without sample preparation - of the active pharmaceutical ingredient (API) salicylic acid in a pharmaceutical ointment using FT-Raman spectroscopy. The calibration curve was modeled by plotting the peak intensity of the vector normalized spectral band between 757 and 784cm(-1) against the known salicylic acid concentrations in standards. At this band, no spectral interferences from the ointment vehiculum (white vaseline) are observed. For the validation of the polynomial model, its fit and its predictive properties were evaluated. The validated model was used for the quantification of 25 ointments, compounded by different retail pharmacists. The same standards and samples were used, both for development and validation of a regression model and for quantitative determination by HPLC - with sample preparation - as described for the related substances of salicylic acid in the Ph. Eur. IV. The quantification results obtained by the FT-Raman method corresponded with the HPLC results (p=0.22), provided that the particle size of salicylic acid in the standards is the same as in the analyzed samples. The non-destructive FT-Raman method is a reliable alternative for the destructive HPLC method, as it is faster and does not require sample pre-treatment procedures.

Calibration↗

PubMed2005

Determination of the relative amounts of three crystal forms of a benzimidazole drug in complex finished formulations by FT-Raman spectroscopy.

A 5% (m/m) premix for animal use was quantitatively characterized for the polymorph composition of its benzimidazole drug substance. Raman spectra of reference samples (pure polymorphs A, B and C in lactose at a concentration of 5%, m/m) were compared with the spectra of benzimidazole samples with a known polymorph composition and with the spectra of uncharacterized premixes. The raw intensities of 78 selected wavenumbers were vector-normalized and application of stepwise linear regression models estimated the relative quantities of the benzimidazole-drug polymorphs A, B and C in the different samples. Modelling results of the samples with known polymorph composition were in compliance with the expected concentrations, validating the proposed methodology. The benzimidazole drug substance in the premixes was predominantly polymorph B. Although statistically not significant, some traces of polymorph A could not be ruled out. Similar analyses were performed to evaluate the solid-state stability of the benzimidazole drug substance in another drug formulation, i.e. a suspension-emulsion. Suspension-emulsions originally determined as containing polymorph B benzimidazole drug substance were stored for 12 months at 25 degrees C/60%RH. FT-Raman spectroscopy revealed that no polymorph transformations occurred during this storage.

Benzimidazoles↗

PubMed2004

In-line monitoring of a pharmaceutical blending process using FT-Raman spectroscopy.

FT-Raman spectroscopy (in combination with a fibre optic probe) was evaluated as an in-line tool to monitor a blending process of diltiazem hydrochloride pellets and paraffinic wax beads. The mean square of differences (MSD) between two consecutive spectra was used to identify the time required to obtain a homogeneous mixture. A traditional end-sampling thief probe was used to collect samples, followed by HPLC analysis to verify the Raman data. Large variations were seen in the FT-Raman spectra logged during the initial minutes of the blending process using a binary mixture (ratio: 50/50, w/w) of diltiazem pellets and paraffinic wax beads (particle size: 800-1200 microm). The MSD-profiles showed that a homogeneous mixture was obtained after about 15 min blending. HPLC analysis confirmed these observations. The Raman data showed that the mixing kinetics depended on the particle size of the material and on the mixing speed. The results of this study proved that FT-Raman spectroscopy can be successfully implemented as an in-line monitoring tool for blending processes.

Fourier Analysis↗

PubMed2004

Development and validation of a direct, non-destructive quantitative method for medroxyprogesterone acetate in a pharmaceutical suspension using FT-Raman spectroscopy.

A simple linear regression method was developed and statistically validated for the direct and non-destructive quantitative analysis--without sample preparation--of the active pharmaceutical ingredient (API) medroxyprogesterone acetate (MPA) in an aqueous pharmaceutical suspension (150 mg in 1.0 ml) using FT-Raman spectroscopy. The linear regression was modelled by plotting the highest peak intensity of the vector normalized spectral band between 1630 and 1590 cm-1 against different MPA standard suspension concentrations. At this band, no spectral interferences from additives in the suspension are observed. The validated model was used for the quantification of a commercial suspension (150 mg in 1.0 ml) of the commercialized preparations. The same standards and samples were used, respectively, for the development and validation of a simple linear regression model and for the quantitative determination by means of HPLC-with sample preparation-as described for the related substances of MPA in the Ph. Eur. IV. The quantification results obtained by the FT-Raman method corresponded with the claimed label concentration (150.01+/-0.96 mg/ml (n=6)). Applying the HPLC method, however, a systematic error was observed (157.77+/-0.94 mg/ml (n=6)). The direct FT-Raman method hence appears the most reliable for the quantification of the MPA component in suspension, compared to the HPLC method that requires sample preparation. The latter method provides a systematic error because the exact volume or density of a suspension sample is unknown. A precise isolation of fixed volumes from a suspension is rather unfeasible because of the continuous sagging of the suspended particles and their sticking to the used materials in the isolation process.

Chromatography, High Pressure Liquid↗