AxisPharm Services

What are oligonucleotides?

Oligonucleotides are usually composed of short chains of nucleotides (deoxyribonucleotides or ribonucleotides) within 20, which can be paired with DNA, mRNA or pre-mRNA by Watson-Crick base pairing principle. With very high selectivity, certain genes are precisely inhibited, and the genes encoding the abnormality are “silenced”, thereby preventing the expression of many “wrong” proteins.

While most oligonucleotide therapies focus on gene silencing, other strategies including splicing regulation and gene activation are advancing, expanding the range of possible therapeutic targets beyond conventional drug therapy.

There are many types of oligonucleotide drugs currently under research, including antisense oligonucleotide (ASO), small interfering RNA (siRNA), microRNA (miRNA), nucleic acid adaptation body (aptamer) and so on.

Oligonucleotides are often used as probes to determine the structure of DNA or RNA, and are used in gene chips, electrophoresis, fluorescence in situ hybridization and other processes.
The DNA (deoxyribonucleic acid) synthesized by oligonucleotide can be used for chain polymerization reaction, which can amplify and determine almost all DNA fragments. Replicas of DNA.
Regulatory oligonucleotides are used to inhibit RNA fragments and prevent their translation into proteins, which can play a certain role in inhibiting the activity of cancer cells.

As a new class of therapeutic modalities, therapeutic oligonucleotides are constantly being tapped for their potential and lead the global R&D wave. However, oligonucleotides are much larger than traditional small molecules, and their preparation involves a large number of synthetic steps, and a typical multi-step cycle of solid-phase synthesis is likely to introduce impurities/invalid sequences, making analysis and characterization more difficult. great difficulty. In addition, oligonucleotides also have some specific physical and chemical properties, such as: usually with a large number of negative charges, phosphorylation to generate PO impurities, hydrolysis of purine bases to form depurine fragments and hydroxyl groups on ribose, these substances are very Difficult to separate from main and full-length products, so oligonucleotide development often relies heavily on mass spectrometry and quantification.

Why Choose Oligonucleotide Analysis from Axispharm?

Our oligonucleotide analysis services include many methods to help you:

– Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to determine the molecular weight of intact oligonucleotides of at least 75 monomer units in size
-Provide sample purity information
– Use MALDI-TOF MS or electrospray tandem mass spectrometry (ES-MS/MS) to confirm the composition/sequence of deoxyribonucleotides containing at least 55 monomer units
– Sequencing of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) (or mixed) oligomers by ESI-MS/MS without pretreatment of phosphorothioate ligation
– Sequencing and analysis of modified nucleotides
– Analysis of oligonucleotide mixtures without the need to separate out individual oligonucleotide species

Both Q-TOF-LC-MS and TQ-LC-MS can be used for mass determination and quantification analysis of therapeutic oligonucleotides.

QTOF-LC-MS is a high-performance liquid chromatography (LC) tandem mass spectrometer (LC-MS/MS) combined with a quadrupole time-of-flight mass spectrometer (Q-TOF). High resolution TOF mass spectrometer can be used for quality characterization, quality control and quantification in the analysis of oligonucleotides.

Quantitative analysis of oligonucleotides can also be achieved by using a high-performance liquid chromatography-triple quadrupole mass spectrometer (TQ-LC-MS). TQ-LC-MS is an LC-MS/MS combining LC and a triple quadrupole mass spectrometer ( TQ). It is possible to carry out selective and supersensitive analysis by multi-reaction monitoring (MRM), and it can be utilized for analysis of pharmacokinetics etc. in the analysis of therapeutic oligonucleotides.

When the difference between the target oligonucleotide and the impurities in the therapeutic agent is the structural difference only due to a slight modification, it is assumed to be undistinguishable by LC-UV detection because the chromatographic separation is difficult. Mass spectrometer based analysis, such as Q-TOF-LC-MS and TQ-LC-MS , on the other hand, are considered to be capable of highly selective detection due to their high mass resolution, mass accuracy, selectivity and sensitivity, even when chromatographic separation is not possible.

Q-TOF-LC-MS and TQ-LC-MS analysis of Oligonucleotides