Raman spectroscopy for the quantitative and qualitative analyses of solid drug formulations of salbutamol

Inhalable drugs are commonly used to treat different kinds of respiratory disorders, such as asthma, coughing, wheezing, and breathing difficulties. Salbutamol is an inhalable drug which is used to treat symptoms of acute obstructive lungs disease and asthma. In this research, Raman spectroscopy technique has been utilized to determine the quality and quantity of solid dosage forms of salbutamol drug. Eight formulations of solid drug Salbutamol, combination of excipients and API, were prepared and analyzed. The Raman spectral features showed significant change in their intensities as directly related to variation in the concentration of formulation. Raman spectral results were further assessed by principal component analysis (PCA) and partial least squares regression analysis (PLSR) which are very potent chemometric tools for the quantitative and qualitative analyses of the pharmaceutical drugs. PCA was found to be useful in discriminating the acquired Raman spectra of various salbutamol drug formulations in solid forms of dosage. Furthermore, PLSR model developed for analyzing the quantitative relationship between different formulated solid dosages of salbutamol drug. The prediction of model and the prediction of an unknown drug formulation's concentration is performed by PLSR model. A value of 0.9079 mg was found to be for the root mean square error of cross-validation (RMSECV) and good fit regression R² was found to be 0.998. Moreover, API concentration (w/w) of unknown formulation of the drug was found to be 8.90 mg (w/w) having actual concentration of 8 mg (w/w).