Determinations of ephedrine in mixtures of ephedrine and pseudoephedrine using diffuse reflectance infrared spectroscopy

The Development of Spectrophotometric and Validated Stability- Indicating RP-HPLC Methods for Simultaneous Determination of Ephedrine HCL, Naphazoline HCL, Antazoline HCL, and Chlorobutanol in Pharmaceutical Pomade Form

BACKGROUND

Allergic rhinitis, acute nasal congestion and sinusitis are one of the most common health problems and have a major effect on the quality of life. Several medications are used to improve the symptoms of such diseases in humans. Pharmaceutical pomade form containing Ephedrine (EPD) HCl, Naphazoline (NPZ) HCl, Antazoline (ANT) HCl, and Chlorobutanol (CLO) is one of them.

OBJECTIVE

For these reasons, this study includes the development of spectrophotometric and chromatographic methods for the determination of EPD HCl, NPZ HCl, ANT HCl, and CLO active agents in the pharmaceutical pomade.

METHOD

In the spectrophotometric method, third-order derivative of the amplitudes at 218 nm n=5 and the first-order derivative of the amplitudes 254 nm n=13 was selected for the determination of EPD, ANT, respectively while NPZ was determined by the second derivative at 234 nm and n=21. Colorimetric detection was applied for assay analysis of CLO at 540 nm. Furthermore, a reverse phase high performance liquid chromatographic (RP- HPLC) method has been developed and optimized by using Agilent Zorbax Eclipse XDB C18 (75 mm x 3.0 mm, 3.5μm) column. The column temperature was 40°C, binary gradient elution was used and the mobile phase consisted of 15 mM phosphate buffer in distilled water (pH 3.0) and methanol, and the flow rate was 0.6 mL min^-1 and the UV detector was detected at 210 nm. The linear operating range was obtained as 11.97-70, 0.59-3, 2.79-30, and 2.92-200 μg mL^-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO respectively.

RESULTS

The LOD values were found to be 3.95, 0.19, 0.92 and 0.96 μg mL^-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO in the spectrophotometric method, respectively. The linear ranges in the RP-HPLC method were 8.2-24.36 μg mL^-1, 0.083 - 0.75 μg/mL, 2.01-7.5 μg mL^-1 and 2.89-24.4 μg mL^-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO, respectively. The LOD values in the validation studies were 2.7, 0.025, 0.66 and 0.86 μg mL^-1 for EPD HCl, NPZ HCl, ANT HCl, and CLO in RP-HPLC method respectively.

CONCLUSION

The results of the spectrophotometric and chromatographic methods were compared and no differences were found between the two methods.

Quantitative analysis of solid samples using modified specular reflectance accessory

Diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) is a fast, reliable and cost effective analytical method, requiring minimal or no sample preparation. It is commonly used in the course of qualitative and quantitative analysis of pharmaceutical ingredients and food. We demonstrate that simpler and cheaper specular reflectance (SR) accessory working in a DRIFTS like mode (SR-DL) can be an alternative for DIRFTS attachment. An application of a modified SR accessory for quantitative analysis of solids samples is presented. As a case study the concentration of cinnarizine in commercial tablets has been determined from DRIFTS and SR-DL infrared (IR) and near-infrared (NIR) spectra recorded using DTGS (deuterated triglicine sulphate) detector in the IR and NIR regions and InGaAs (indium-gallium arsenide) detector in the NIR range. Based on these spectra Partial Least Squares (PLS) models were constructed and relative standard errors of prediction (RSEP) were calculated for the calibration, validation and analysed data sets. They amounted to 2.4-2.5%, 2.1-2.7% and 2.0-2.6% for the DRIFTS attachment while 2.1-2.2%, 2.0-2.3% and 1.9-2.6%, respectively, for the modified SR accessory. Obtained error values indicate that modified SR accessory can be effectively used for quantification of solid pharmaceutical samples in the mid- and near-infrared regions.

Analysis of Quil A–phospholipid mixtures using drift spectroscopy

The aim of this study was to investigate molecular interactions between Quil A and phosphatidylcholine in the solid state using diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS). Analysis of the interactions was characterized on the different regions of phosphatidylcholine: hydrophobic chain, interfacial and headgroup regions. The spectra of the hydrocarbon region of phosphatidylcholine alone compared to that for the binary mixture of Quil A and phosphatidylcholine were similar. These findings suggest that Quil A did not cause conformational disorder of the fatty acyl chains of the phospholipid. In contrast, a shift in the wavenumber of the choline group and a broad band in this moiety indicate a modification of the phospholipid in the headgroup region due to interaction between Quil A and phosphatidylcholine. These results suggest possibly ionic interactions between the negatively charged glucuronic acid moiety of the Quil A molecule with the positively charged choline group. The findings could also be the result of conformational changes in the choline group because of the intercalation of sugar moieties in Quil A between the choline and phosphate groups due to hydrogen bonding. Shift of wavenumbers to lower values on the carbonyl group was observed suggesting hydrogen bonding between Quil A and phosphatidylcholine. The difference in degrees of wavenumber shift (choline>phosphate>carbonyl group) and observed broad bands indicated that Quil A preferentially interacted with phosphatidylcholine on the hydrophilic headgroup. Cholesterol influenced such interactions at relatively high concentration (60%, w/w).

Integrating X-ray fluorescence and infrared imaging microspectroscopies for comprehensive characterization of an acetaminophen model pharmaceutical

The integration of full spectral images using the complementary microspectroscopic imaging techniques X-ray fluorescence and Fourier transform infrared is demonstrated. This effort surpasses previous work in that a single chemometric software package is used to elicit chemical information from the integrated spectroscopic images. Integrating these two complementary spectroscopic methods provides both elemental and molecular spatial distribution within a specimen. The critical aspect in this work is using full spectral maps from each pixel within the image and subsequent processing with chemometric tools to provide integrated chemical information. This integration enables a powerful approach to more comprehensive materials characterization. Issues addressed include sample registration and beam penetration depth and how each affects post-processing. An inorganic salt and an acetaminophen pharmaceutical model mixture demonstrate the power of integrating these techniques with chemometric software.