Category: Formulation and Quality
Purpose: Process Analytical Technology (PAT) uses equipment with rapid responses for monitoring, during the manufacturing process, the critical attributes of a product to guarantee its quality. Near Infrared Spectroscopy (NIRS) combined with chemometrics is a PAT tool which allows to obtain chemical and physical information from organic molecules. NIRS utility is attributed to its ability to perform non-destructive analysis; reduce sampling preparation steps and the environment affectation, since it avoids the use of solvents. NIRS also provide a rapid response, reducing time of analysis obtaining accurate and precise results, therefore, NIRS has become an attractive tool in the pharmaceutical industry.
The aim of this study was to implement a PAT tool to perform a quantification method for the analysis of quantification of acetaminophen in bulk and in the semisolid matrix of a Soft Gelatin Capsule (SGC), using NIR diffuse reflectance spectroscopy and chemometrics. This study is important because NIRS is used to quantify a pharmaceutical active in a suspension, which reduces the precision and accuracy of NIRS method. This improvement was achieved using pretreatment technics.
Methods: The product used in this work was Acetaminophen 500 mg SGC. A SGC is a dosage form which is formed by an outer portion, the Shell and an inner portion the medicine or the fill (see Figure 1). In this case the medicine is a suspension of acetaminophen in PEG 600 and other excipients. For this study, a set of calibration samples were prepared into the range of 0 to 130% of the target concentration of acetaminophen in the product (54,3 g/100g). In addition, samples of nine commercial batches of Acetaminophen were obtained, five of these batches were included within the calibration set and four batches were included in an external validation set, used to evaluate the prediction capacity of the proposed models.
Figure 1. Soft-Gelatin Capsule
The spectra of the samples were acquired using a NIR-FLEX-N-500 spectrophotometer (Brand: BUCCHI), by diffuse reflectance, 32 scans and 8 cm-1 resolution, with a spectral range of 4000-10,000 cm-1. Samples were analyzed in triplicate and 4 spectra were taken from each replicate. The spectral treatment software was NIRCAL 5.5V. In this study a reverse phase HPLC method was used as reference method to quantify the concentration of the samples used in the NIR calibration model.
The spectra of the calibration samples were correlated with the independent variables that are the concentrations of the samples, through a regression by partial least squares PLS. Seven PLS regressions models were created, varying the spectral range, the type pretreatment and the number of factors in order to find the equation that best models or predicts the spectral signal with respect to the concentration.
The predictive capacity of the PLS model was evaluated using statistical parameters such as: Squared Error of Calibration (SEC) and Prediction (SEP), R2 of Calibration (R2Cal) and validation (R2Val) and percentage of recovery of the samples obtained with the PLS model Vs HPLC results.
Results: Figure 2a shows the spectra of the calibration samples and commercial batches of acetaminophen. In Figure 2b a Standard Normal Variate (SNV) pretreatment was applied to the original spectra, the dispersion of the spectra decreased in the pretreated spectra respect to the original. With the objective of subtracting the chemical information and minimizing variations due to physical changes, other pretreatments were also evaluated as: first and second derivative and savitzki golay.
Figure 2a) Original Spectra of samples of acetaminophen at different concentrations. Figure 2b) Pretreated Spectra of acetaminophen samples at different concentrations, pretreated with Standard Normal Variate (SNV).
Original and pretreated spectra were used and seven PLS models were obtained. These models get the following results: SEC: from 0.004 to 0.012%; SEP: from 0.007 to 0.091%; R2Cal: from 0.995 to 1.000 and R2Val: from 0.992 to .0999; the percentage of recovery was from 97.31 ± 3.4 to 103.7 ± 0.9.
Results obtained shows that, compared with the other models, PLS model No 6 presented better recovery percentage with respect to the results of the reference method, better relative standard deviation and low prediction error.
Conclusion: The proposed method of quantification of a suspension of acetaminophen, based on NIR spectroscopy of diffuse reflectance and PLS regression and SNV pretreatment, gives accurate and precise results, which can be comparable with HPLC results, however, proposed method is less time consuming, since it reduces the sampling preparation step and it is environment-friendly, since it avoids the use of solvents. For this reason, the proposed method is an excellent alternative to be used in quality control analysis for this product.
Sofía Pareja Hernández– Barranquilla, Atlantico, Colombia
Miriam Fontalvo Gómez– Puerto Colombia, Atlantico, Colombia
Jorge Ropero Vega– Puerto Colombia, Atlantico, Colombia
JOE VILLA MEDINA– Director Research and Development, PROCAPS, Barranquilla, Atlantico, Colombia
Joe Villa– Director of Product Development USA & EU, Procaps, Barranquilla, Colombia