Bioanalytical Method by Column-Switching With Direct Injection of Human Plasma for Determination of Sulphonylureas

Abstract

Sulphonylureas are widely used in the treatment of Diabetes mellitus, one of the main causes of death in human population. Their determination is essential in pharmacological research and in the development of new drugs. Generally, determination of sulphonylureas in biological matrices is performed using conventional sample preparation techniques, which frequently leads to an increase of analysis time and errors. In this context, a bioanalytical method for the simultaneous determination of sulphonylureas by direct injection of human plasma was developed and optimized. An automated column-switching high performance liquid chromatographic system with a restricted access media (RAM) column coupled to a fused-core column was employed. At the first dimension, a RAM column with mobile phase of ultrapure water pH 6.0 at a flow-rate of 1.0 mL min-1 was used. The valve switching time was 3 minutes. At the second dimension, a C18 guard-column coupled to a C18 fused core column with mobile phase of acetonitrile and 10 mM phosphate buffer pH 3.0 (54:46 v/v) at a flow-rate of 0.8 mL min-1 were employed. The column switching system was performed in backflush configuration with an analyte elution time of 1 minute. Flufenamic acid was used as the internal standard. The mean plasma protein exclusion percentage by the RAM-column was 104.5%. The developed and optimized method showed to be fast and simple, allowing the direct injection of biological sample into the chromatographic system and the simultaneous determination of three sulphonylureas in only 12 minutes, including the sample treatment, separation and detection.

Transdermal Delivery of Glimepiride: A Novel Approach Using Nanomicelle-Embedded Microneedles

“…Human volunteers were used for the in vivo evaluation to compare the pharmacokinetic parameters of GM-DMNs with the commercially available GM Tablet [ 51 ]. Six healthy male volunteers were selected based on medical history and physical examination, with a mean age of 21 ± 0.4 years, a mean height of 174.5 ± 3.8 cm, and a mean weight of 70.6 ± 1.6 kg [ 52 ]. The cross-over study was designed with a 7-day washout period to mitigate the influence of potential confounding variables, such as age, body weight, and genetics, that could significantly affect the outcomes of the study [ 53 ].…”

“…During phase 1, the first group (n = 6) received fabricated microneedles containing approximately 240 µg of GM, and the microneedles patches were applied at a force of 1.6 N with a spring applicator (Micropoint Technologies Pvt, Ltd. Singapore), and the second group (n = 6) received 1 mg GM oral tablets, as illustrated in Figure 6, and vice versa after the washout time period. Blood samples (5 cc) from the forearm vein before administration, and at 0.5, 1, 2, 4, 6, 12, 24, 36, and 48 h, postdosing was collected with a 22-gauge needle and transferred into EDTA tubes, plasma was collected from the samples by centrifuging at 1500× g for 15 min at 4 °C [52]. The plasma samples were stored at −20 °C prior to analysis.…”

“…Skin redness was evaluated using the ECRC scale. Pain Blood samples (5 cc) from the forearm vein before administration, and at 0.5, 1, 2, 4, 6, 12, 24, 36, and 48 h, postdosing was collected with a 22-gauge needle and transferred into EDTA tubes, plasma was collected from the samples by centrifuging at 1500× g for 15 min at 4 • C [52]. The plasma samples were stored at −20 • C prior to analysis.…”