Analysis of changes in the proteomic profile of porcine corpus luteum during different stages of the oestrous cycle: effects of PPAR gamma ligands.

CONTEXT: The corpus luteum (CL) is an endocrine gland in the ovary of mature females during the oestrous cycle and pregnancy. There is evidence of a relationship between the secretory function of the CL and PPARs. AIMS: In this study, we investigated the changes in the proteome of the CL in relation to the phase of the oestrous cycle and the impact of PPARγ ligands on the proteomic profile of the CL during the mid- and late-luteal phase of the oestrous cycle. METHODS: The porcine CL explants were incubated in vitro for 6h in the presence of PPARγ ligands (agonist pioglitazone, antagonist T0070907) or without ligands. Global proteomic analysis was performed using the TMT-based LC-MS/MS method. KEY RESULTS: The obtained results showed the disparity in proteomic profile of the untreated CL - different abundance of 23 and 28 proteins for the mid- and late-luteal phase, respectively. Moreover, seven proteins were differentially regulated in the CL tissue treated with PPARγ ligands. In the mid-luteal phase, one protein, CAND1, was downregulated after treatment with T0070907. In the late-luteal phase, the proteins SPTAN1, GOLGB1, TP53BP1, MATR3, RRBP1 and SRRT were upregulated by pioglitazone. CONCLUSIONS: Comparative proteomic analysis revealed that certain proteins constitute a specific proteomic signature for each examined phase. Moreover, the study showed that the effect of PPARγ ligands on the CL proteome was rather limited. IMPLICATIONS: The results provide a broader insight into the processes that may be responsible for the structural luteolysis of the porcine CL, in addition to apoptosis and autophagy.

Mean centering-triple divisor and ratio derivative-zero crossing for simultaneous determination of some diabetes drugs in their quaternary mixture with severely overlapping spectra.

Two ratio derivative spectrophotometric methods were performed for the simultaneous analysis of metformin hydrochloride, empagliflozine, linagliptin, and pioglitazone hydrochloride in their synthetic mixtures without prior chemical separation. The drugs are approved for the treatment of type 2 diabetes. Despite the various advances in the management of diabetes, it remains to be the major cause of disability and morbidity, including blindness, amputation, heart disease, peripheral neuropathy, and kidney disease. These techniques consisted of several steps using ratio and derivative spectra. The absorption spectra of the mentioned drugs were recorded in the range of 200-350 nm, which have the concentration ranges of 1.0-10, 2.5-30, 5.0-40, and 2.5-30 µg mL-1 for metformin hydrochloride, empagliflozine, linagliptin, and pioglitazone hydrochloride, respectively, using zero-order spectra. The mean centring of ratio spectra combined with triple divisor were measured at the amplitude values 242, 256, 272 and 296 nm for metformin hydrochloride, empagliflozine, linagliptin and pioglitazone hydrochloride, respectively; the derivative ratio spectra-zero crossing quantifies the amplitude value of the analytical signal at 234, 244, 260 and 280 nm for metformin hydrochloride, empagliflozine, linagliptin and pioglitazone hydrochloride, respectively. The method was validated according to the ICH guidelines, accuracy, precision and repeatability were found to be within the acceptable limits. Finally, statistical comparisons between the proposed methods and with the reported methods with respect to accuracy and precision show that no significant difference was found by using Student's t-test, the F-test and one-way ANOVA.

Detecting and Quantifying Microscale Chemical Reactions in Pharmaceutical Tablets by Stimulated Raman Scattering Microscopy.

It has been estimated that approximately 50% of all marketed drug molecules are manufactured and administered in the form of salts, often with the goal of improving solubility, dissolution rate, and efficacy of the drug. However, salt disproportionation during processing or storage is a common adverse effect in these formulations. Due to the heterogeneous nature of solid drug formulations, it is essential to characterize the drug substances noninvasively at micrometer resolution to understand the molecular mechanism of salt disproportionation. However, there is a lack of such capability with current characterization methods. In this study, we demonstrate that stimulated Raman scattering (SRS) microscopy can be used to provide sensitive and quantitative chemical imaging of the salt disproportionation reaction of pioglitazone hydrochloride (PIO-HCl) at a very low drug loading (1% w/w). Our findings illuminate a water mediated pathway of drug disproportionation and highlight the importance of noninvasive chemical imaging in a mechanistic study of solid-state chemical reactions.

Applications of Fourier transform infrared spectroscopic method for simultaneous quantitation of some hypoglycemic drugs in their binary mixtures.

Cost-effective, green, simple and reliable transmission Fourier-transform infrared (FTIR) spectroscopic method was developed for simultaneous analysis of hypoglycemic drugs in their binary mixtures for the first time. The FTIR method was applied for the determination of vildagliptin (VILD), glimepiride (GLIM) and pioglitazone (PIOG) in binary mixture with metformin (METF). The method was validated according to the International Conference on Harmonization (ICH) guidelines. The obtained results (expressed in peak areas) are linear with concentration in the range of 0.61-20, 0.26-24 and 0.37-4 µg/mg for VILD, PIOG and GLIM, respectively while the linearity ranges for METF were 0.40-200, 0.26-800 and 0.19-1000 µg/mg with VILD, PIOG and GLIM, respectively. The limits of detection (LODs) were 0.20, 0.08 and 0.12 µg/mg for VILD, PIOG and GLIM, respectively while METF LODs were 0.13, 0.08 and 0.06 µg/mg with VILD, PIOG and GLIM, respectively. The FTIR method has been successfully applied for the determination of the cited binary mixtures in its pharmaceutical tablets and the obtained results showed satisfactory % recovery.