Comparison of analytical methods for quality control of pharmaceutical formulations containing glutathione

Abstract

SummaryThe aim of this investigation was the study and development of analytical procedures suitable for the assay of glutathione (GSH) in pharmaceutical formulations. Two are based on isocratic HPLC with a 250 mmx 4.6 mm i.d., 5 ~m C18 column and UV detection. In the first procedure sample solutions were injected without pretreatment whereas in the second the samples were injected after derivatization with Ellman's reagent which forms an easily detectable adduct with GSH. Good linearity was obtained over the range 0.12-6.00 x 10 --4 M for the direct procedure and 0.25--3.00 x 10 -4 M for the derivatization procedure. The precision and rapidity of analysis were also good for both methods. The third method is based on capillary zone electrophoresis (CZE) in a 27 cm x 75 pm i.d untreated fused silica capillary containing pH 7 phosphate buffer. All results are in good agreement with a spectrophotometric procedure used as reference method.

Controlled Insulin Release from Chitosan Microparticles

“…Spectrophotometric and spectrofluorimetric methods were selected for the insulin determination, among other analytical methods, for their rapidity, sensitivity and feasibility [26] . Figure 3a reports the UV absorption spectrum of a standard solution of insulin (14.2 UI/mL), showing a band with a maximum at 276.4 nm.…”