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ACD/Labs Blog

Arvin Moser
In this final installment of the series on Drug Development, we examine stage 4 and the effort involved in Drug Manufacturing and Process. The 4th stage begins with a large scale production of the new drug, followed by formulation studies and then ending with regulatory reviews of the entire process before the drug can be...

Arvin Moser
Drug Trials commence with in vitro and in vivo experiments on nonhuman subjects and observing the effects of the candidate drug(s). These are commonly referred to as the pre-clinical trials. Once safe and effective thresholds have been set, the candidate drug(s) can be administered to human subjects and thus begin the clinical trials. The clinical...

Arvin Moser
The main focus surrounding the Drug Design stage (see diagram in Part 1) is to optimize the hit compound(s) and produce analogues that will increase the activity at the target site. Lead optimization is accomplished through minor modifications of the hit compound. In Drug Design, medicinal chemists aim to build a diverse library of compounds...

Arvin Moser
Following the diagram presented in Part 1, the Drug Discovery stage begins with the identification of a target site that is linked to a disease. (Note: some researchers refer to this as the pre-Drug Discovery stage.) The main goal behind the Drug Discovery stage is to identify or envision a hit compound(s) that can offer...

Arvin Moser
Many new medicinal drugs produced by pharmaceutical companies follow a very similar pathway starting from the inception of the project idea and ending at the shelves of a pharmacy. Each stage in the development of the drug involves various types of chemists, each lending their expertise at synthesizing, extracting, analyzing and testing the new drug....

Arvin Moser
Whenever a GC column is used to identify and/or quantify a sample, the column stationary phase can bleed into the MS source along with the sample. High column bleed can hinder the analysis of a sample. The resulting spectral interference typically manifests itself as discrete peaks and/or an increase in the drift of the baseline, which...

Arvin Moser
Sugar residues (saccharides) can be tough to elucidate. They tend to have 1H NMR spectrum with overlapping and sometimes poorly-resolved 1H signals, and the 2D NMR data presents lots of ambiguous assignments. With a little practice, an elucidator can quickly pick out a sugar moiety based on a minimal amount of NMR data. For a...

Arvin Moser
There are many challenges present in deciphering correlations on an HMBC experiment. Barring any data collection issues, most of the challenges will arise from signals that are overlapping, thus, adding an element of ambiguity. The 1H -13C HMBC spectrum below shows a correlation between the 13C at 71.2 ppm and the overlapping 1H signals at...

Arvin Moser
TLC (Thin Layer Chromatography) offers a simple approach to identifying a solvent(s) for separating out a mixture, monitoring a reaction to completion, etc. Furthermore, the TLC plates can be stained to identify the presence or absence of various functional groups such as amines, ketones, etc. This qualitative experiment does offer various drawbacks. The process of...

Arvin Moser
Functional groups such as allene (C=C=C) and cumulene (C=C=C=C) present an interesting challenge in an elucidation project, especially when an elucidator is not expecting them. The 13C chemical shifts for allene carbons are typically expected at 80, 200 and 100 ppm +/- ~20 ppm per shift. The confusion, or better described as bias, arises at...

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