Evaluation of the quality of formulations containing lactase (β-galactosidase) employing gel electrophoresis and cell phone

Abstract

A quantification method of the lactase enzyme in pharmaceutical formulations is proposed employing digital images obtained from a cell phone camera and processed using the colorimetric application. The use of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) made it possible to identify the lactase enzyme, to fractionate possible protein impurities and to evaluate the degradation of lactase present in the analyzed formulations. In addition, gel electrophoresis made it possible to determine lactase free of matrix interference. The proposed method presented limit of quantification of 0.002 mg lactase (0.03 FCC), using external calibration. Recoveries of lactase added to the samples were in the range 78-104%. The concentrations found in different pharmaceutical formulations samples containing lactose were in the range 7-621 mg (104-9319 FCC). The relative standard deviations (RSD) were in the range of 3-13%. Of the six samples analyzed, only two (#S2 and #S5) were in agreement with the sample label description.

PhotoMetrix and colorimetric image analysis using smartphones

“…Reproduced with permissions from Helfer et al 125 ; Springer F I G U R E 9 Fragmented chromatograms of different mass (0-0.38 mg) of standard lactase (90 kDa) on gel electrophoresis along with molecular weight marker proteins and calibration curve for lactase. Reproduced with permissions from Dionizio et al 128 ; BrJAC methodology. The results obtained by the recovery tests ranged from 78% to 104%, demonstrating the potential of the proposed methodology for the quantification of lactase via SDS-PAGE through digital image analysis.…”

“…A methodology for quantification of the lactase enzyme present in pharmaceutical formulations using digital images taken by a mobile phone camera and processed by the PhotoMetrix ® was proposed by Dionizio et al 128 For lactase quantification, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used; images were captured at a controlled distance, and cell flash was used. The app univariate mode was explored, where channel B was chosen for quantification.…”

“…Through the researches that used PhotoMetrix ® early presented, it is possible to visualize the versatility of this application, because it was used in different analysis, presenting significant results. It is possible to carry out direct analysis, 126,136 that is, without performing sample preparation, analysis of solid 120 and liquid samples, [131][132][133]135 with the use of chambers to store the samples, 121,124,125,129,134 or without lighting control accessories, 127 in addition to allowing the sample to be conditioned in different ways to capture images such as paper 122,123 and SDS-PAGE 128,130 for example. Figure 12 shows four different ways of acquiring images related to the previously presented articles that used Photo-Metrix app in their analysis, where in some works, chambers were made to capture images, and in others, the image acquisition was performed without light control.…”