To enhance patient compliance toward treatment in diseases like diabetes, usually a combination of drugs is prescribed. Therefore, an anti-diabetic fixed-dose combination of 2.5 mg of linagliptin 500 mg of metformin was taken for simultaneous estimation of both the drugs by reverse phase-high performance liquid chromatography (RP-HPLC) method. The present study aimed to develop a simple and sensitive RP-HPLC method for the simultaneous determination of linagliptin and metformin in pharmaceutical dosage forms. The chromatographic separation was designed and evaluated by using linagliptin and metformin working standard and sample solutions in the linearity range. Chromatographic separation was performed on a C18 column using a mobile phase of 70:30 (v/v) mixture of methanol and 0.05 M potassium dihydrogen orthophosphate (pH adjusted to 4.6 with orthophosphoric acid) delivered at a flow rate of 0.6 mL/min and UV detection at 267 nm. Linagliptin and metformin shown linearity in the range of 2-12 μg/mL and 400–2400 μg/mL respectively with correlation co-efficient of 0.9996 and 0.9989. The resultant findings analyzed for standard deviation (SD) and relative standard deviation to validate the developed method. The retention time of linagliptin and metformin was found to be 6.3 and 4.6 min and separation was complete in <10 min. The method was validated for linearity, accuracy and precision were found to be acceptable over the linearity range of the linagliptin and metformin. The method was found suitable for the routine quantitative analysis of linagliptin and metformin in pharmaceutical dosage forms.

in Wiley Online Library (wileyonlinelibrary.com).Inspired by the concept of molecular hybridization, a series of new isatin-pomalidomide hybrids (9a-9g) were designed, synthesized, characterized, and evaluated for in vitro cytotoxic activity against U266B1 and RPMI 8226 multiple myeloma cell lines. Sandmeyer methodology and N-halomethylketo alkylation reaction are the two important reactions involved in the synthesis of isatin-pomalidomide hybrids (9a-9g). All the synthesized compounds (3a-3d, 4, 5, 6, and 9a-9g) were characterized by using IR, mass, 1 H-NMR, and 13 C-NMR spectral techniques. The efficacy of all the synthesized compounds was tested against the aforementioned cell lines by employing MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) standard protocols while using pomalidomide as a standard. The test concentrations used in the MTT assay were 1, 10, 20, 30, and 40 μM, and the period of incubation was 24 h. All the synthesized compounds were found to have moderate to greater cytotoxic activity against the aforementioned cell lines. Among them, synthesized hybrids 9f (IC 50 , U266B1 = 5.15 ± 0.72 μM, RPMI8226 = 11.66 ± 0.79 μM) and 9g (IC 50 , U266B1 = 2.50 ± 0.37 μM, RPMI8226 = 6.70 ± 0.55 μM) displayed better cytotoxic activity against both the cell lines used in the present study.

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A series of new isatin–mesalamine conjugates (9a–g) were synthesized via conjugation of isatin (3a) and its derivatives (3b–3d, 4, 5, and 6) with mesalamine (7) by using chloroacetyl chloride as a bifunctional linker. Compounds 3a–3d were prepared by employing Sandmeyer reaction. Compounds 4, 5, and 6 were obtained from isatin (3a) via previously reported methods. The synthesized compounds were characterized by IR, mass, 1H NMR, and 13C NMR spectral techniques. Synthesized compounds (3a–d, 4, 5, 6, and 9a–g) were evaluated for in vitro antioxidant activity by DPPH assay method using ascorbic acid as standard. Hybrids 9b (IC50 = 368.6 ± 3.5 μM) and 9f (IC50 = 335.1 ± 2.9 μM) showed better antioxidant activity than its parent compounds such as 3a (IC50 = 556.8 ± 2.9 μM), 5 (IC50 = 511.9 ± 3.6 μM), and 7 (IC50 = 768.9 ± 2.7 μM). Acetic acid‐induced ulcerative colitis in rat model was chosen to examine the antioxidant potential of the synthesized hybrids (9b and 9f) in the amelioration of ulcerative colitis. Colonic myeloperoxidase and malondialdehyde enzymes were used as biomarkers of anti‐ulcerative colitis activity. In the present study, hybrids 9b and 9f reduced the levels of colonic myeloperoxidase and malondialdehyde enzymes significantly (p < 0.05) when compared with control (colitic), at a dose (0.03 mM/12.5 mg/kg b.w. p.o.) (50%) less than that of its parent moieties mesalamine (0.16 mM/25 mg/kg) and isatin (0.16 mM/25 mg/kg). Thus, the molecular hybridization was proved to be significant in enhancing the activity of hybrids 9b and 9f by reducing the dose.

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