A comprehensive review of sources of nitrosamine contamination of pharmaceutical substances and products.

N-nitrosamines are carcinogenic impurities most commonly found in groundwater, treated water, foods, beverages and consumer products. The recent discovery of N-nitrosamines in pharmaceutical products and subsequent recalls pose a significant health risk to patients. Initial investigation by the regulatory agency identified Active Pharmaceutical Ingredients (API) as a source of contamination. However, N-nitrosamine formation during API synthesis is a consequence of numerous factors like chemistry selection for synthesis, contaminated solvents and water. Furthermore, apart from API, N-nitrosamines have also been found to embed in the final product due to degradation during formulation processing or storage through contaminated excipients and printing inks. The landscape of N-nitrosamine contamination of pharmaceutical products is very complex and needs a comprehensive compilation of sources responsible for N-nitrosamine contamination of pharmaceutical products. Therefore, this review aims to extensively compile all the reported and plausible sources of nitrosamine impurities in pharmaceutical products. The topics like risk assessment and quantitative strategies to estimate nitrosamines in pharmaceutical products are out of the scope of this review.

Synthesis, Characterization and Biological Evaluation of Indole-Pyrazole Amalgamated α-Cyano Substituted Chalcones.

BACKGROUND: Indole and pyrazole constitute a major class of biologically active scaffolds. The amalgamation of two or more pharmacophores would generate novel molecular templates that are likely to unveil remarkable biological properties. OBJECTIVE: An efficient and high yielding synthesis of indole-pyrazole integrated α-cyano substituted chalcones and their in vitro anti-breast cancer and antioxidant evaluation. METHODS: The synthesis of a series of indole-pyrazole amalgamated α-cyano substituted chalcones (6a-o) was achieved by reacting substituted 3-cyanoacetyl indole 2 with substituted pyrazole aldehyde 5 in the presence of piperidine. All the newly synthesized compounds have been characterized by IR, 1H NMR and HRMS spectroscopy. RESULTS: Anti-breast cancer evaluation of the synthesized compounds in vitro against MCF-7 cell line revealed high anti-breast cancer activities. Amongst the compounds screened 6f, 6g, 6h, 6c, 6d, 6e, 6i and 6k unveiled excellent activity against breast carcinoma (GI50 <0.1µM) as good as adriamycin (GI50 <0.1µM). The compounds were also screened against the normal Vero monkey cell line and the results demonstrated more selectivity against MCF-7. On the other hand, compounds 6b, 6c, 6d, 6h and 6i have shown moderate DPPH and NO radical scavenging activity. CONCLUSION: Most of the synthesized compounds exhibited significant antitumor activities. These results further support its safety margin by studying the activity on normal Vero monkey cell line. These results acclaim the possible use of these compounds for the design and development of potent anti-breast cancer agents.

Synthesis, Biological Evaluation and Molecular Dynamics Simulation Studies of Novel Diphenyl Ethers.

BACKGROUND: The well-known antibacterial agent Triclosan (TCL) that targets bacterial enoylacyl protein reductase has been described to inhibit human fatty acid synthase (FASN) via the enoylacyl reductase domain. A Literature survey indicates that TCL is selectively toxic to cancer cells and furthermore might indeed reduce cancer incidence in vivo. A recent study found that TCL inhibits FASN by acting as an allosteric protein-protein interface (PPI) inhibitor. It induces dimer orientation changes that effect in a downstream reorientation of catalytic residues in the NADPH binding site proposing TCL as a viable scaffold to design a superior molecule that might have more inhibitory potential. This unveils tons of potential interaction space to take advantage of future inhibitor design. OBJECTIVES: Synthesis of TCL mimicking novel diphenyl ether derivatives, biological evaluation as potential antiproliferative agents and molecular docking and molecular dynamics simulation studies. METHODS: A series of novel N-(1-(3-hydroxy-4-phenoxyphenyl)-3-oxo-3-phenylpropyl)acetamides (3a-n) and N-(3(3-hydroxy-4phenoxyphenyl)-3-oxo-1-phenylpropyl) acetamides (6a-n) were designed, synthesized, characterized and evaluated against HepG2, A-549, MCF-7 and Vero cell lines. The induction of antiproliferative activity of selected compounds (3d and 6c) was done by AO/EB (acridine orange/ethidium bromide) nuclear staining method, DNA fragmentation study, and cell cycle analysis was performed by flow cytometry. Molecular docking and dynamics simulation study was also performed. RESULTS: Among the tested compounds, compound 3d was most active (IC50 13.76 ± 0.43 µM) against A-549 cell line. Compounds 3d and 3g were found to be moderately active with IC50 30.56 ± 1.1 µM and 25.05 ± 0.8 µM respectively against MCF-7 cell line. Morphological analysis of A-549 cells treated with 3d and 6c clearly demonstrated the reduction of cell viability and induction of apoptosis. DNA fragmentation was observed as a characteristic of apoptosis in treated cells. Further, cell cycle analysis by flow cytometry confirmed that compounds 3d and 6c significantly arrested the cell cycle at the G0/G1 phase. Molecular docking study demonstrated that these compounds exhibit high affinity for the human fatty acid synthase (hFASN) target. Molecular dynamics simulation study of the most active compound 3d was performed for calculating binding free energies using Molecular Mechanics-Generalized Born Surface Area (MM/GBSA). CONCLUSION: Compound 3d (IC50 13.76 ± 0.43 µM) has been identified as a potential lead molecule for anticancer activity against A-549 cells followed by 3l, 6c, and 3g. Thus, the design of diphenyl ether derivatives with enhanced affinity to the binding site of hER may lead to the discovery of potential anticancer agents.

Simultaneous improvement of solubility and permeability by fabricating binary glassy materials of Talinolol with Naringin: Solid state characterization, in-vivo in-situ evaluation.

The aim of the current study was to prepare binary amorphous forms of Talinolol (TLN) by using Naringin (NRG) as a stabilizing agent. The secondary objective of this study was to study the effect of P-gp inhibitor NRG on the P-gp probe drug TLN. The binary amorphous samples were prepared by quench cooling technique in the molar ratios TLN:NRG (1:1), TLN:NRG (1:2), TLN:NRG (2:1). The prepared samples were characterized by DSC, FTIR and XRD. Amorphicity of the prepared binary amorphous samples was confirmed by spotting diffuse halo in the diffractograms and further corroborated by detecting glass transition event (Tg) in the thermograms of the respective samples. The Tgs for all prepared systems were found above room temperature, the highest being 45.43 °C. The systems were found physically stable at 25 °C and 40 °C at dry conditions for 60 days. The temperature stability of prepared amorphous forms may be attributed to strong intermolecular hydrogen bond interaction between TLN and NRG, which was confirmed by Gordon-Taylor calculations and FTIR data. The solubility of TLN in amorphous form was increased by approximately 9-fold as compared to its crystalline counterpart. The in-vivo bioavailability study conducted on wistar rats demonstrated 5.4-fold increase in the AUC0-t value for TLN as compared to its crystalline counterpart. Further to learn the contribution of P-gp inhibition by NRG on the permeability of TLN, In-vitro single pass perfusion studies were conducted on the ileum of wistar rats. The permeability of TLN in rat ileum in the presence of NRG was significantly increased to 3.16×10(-5) cm/s as compare to control value 2.48×10(-5) cm/s. The current study demonstrated the ability of binary amorphous technology to simultaneously overcome both the BCS barriers i.e. solubility and permeability.