Metabolomics and marker-based stability studies of methanol extract of seeds of Syzygium cumini L.

Though, herbal medicines are prone to deterioration upon storage due to their complex nature, but less attention has been paid to investigating stability of such products to assign shelf-life. Therefore, the present study aimed to assess the accelerated stability of methanolic extract of seeds of Syzygium cumini. The extract was kept at three different storage conditions (30oC/60% RH, 40oC/75% RH and 60oC/85% RH) for a period of 6 months. The samples withdrawn at 0 (before starting the study), 1, 2, 3, 4 and 6 months were analyzed to get UV-Visible metabolomics fingerprints and determine caffeic acid contents using RP-HPLC. The comparison of metabolomics fingerprints indicated that the extract was stable for 1 month at all the three storage conditions. However, caffeic acid contents were found to be intact for a longer period of time. Following the zero order degradation, caffeic acid was predicted to be stable for more than 3 years, if kept at 25oC. The results of the present study indicate that metabolomes of methanol extract of seeds of Syzygium cumini change very fast, suggesting the development of stable formulations.

Development and validation of a stability-indicating RP-HPLC-FLD method for determination of 5-[(4-chlorophenoxy) methyl]-1, 3, 4-oxadiazole-2-thiol; A novel drug candidate.

The present study describes the development and validation of a simple high performance liquid chromatographic method for the determination of a novel drug candidate, 5-[(4-chlorophenoxy) methyl]-1, 3, 4-oxadiazole-2-thiol. The stability-indicating capacity of the method was evaluated by subjecting the compound's solution to hydrolytic, oxidative, photolytic, transition metal- and thermal- stress. The chromatographic separation was achieved over a C18 column (Promosil, 5 µm, 4.60 × 250 mm), maintained at 25°C, using an isocratic mobile phase comprising a mixture of acetonitrile and acidified water of pH 2.67 (1:1, v/v), at a flow rate of 1.00 mL/min and detection using a fluorescent light detector (excitation at 250 nm and emission at 410 nm). The Beer's law was followed over the concentration range 2.50-50.00 µg/ml. The recovery (98.56-100.19%, SD <5%), intraday accuracy and precision (97.31-100.81%, RSD <5%), inter-day accuracy and precision (97.50-100.75%, RSD <5%) and intermediate accuracy and precision (98.10-99.91%, RSD <5%) indicated that the method was reliable, repeatable, reproducible and rugged. The resolution and selectivity factors of the compound's peak from the nearest resolving peak, particularly in case of dry heat and copper metal stress, were found to be greater than 2 and 1, respectively, which indicated specificity and selectivity. The compound was extensively decomposed in alkaline-hydrolytic, oxidative, metal- and dry heat- stress. However, the compound in acidic and neutral conditions was resistant to photolysis. The results of the present study indicate that the developed method is specific, selective, sensitive and suitable, hence, may be used for quality control, stability testing and preformulation studies.