Oligonucleotide APIs Supplier & Companies Serving Austria

Chemical Backbones & Sugar Modifications

Unmodified single- or double-stranded RNA/DNA molecules are susceptible to rapid degradation by endogenous serum nucleases (phosphodiesterases). To overcome enzymatic hydrolysis and enhance thermal stability ($T_m$), Gentolex incorporates state-of-the-art nucleoside modifications:

• Phosphorothioate (PS) Internucleotide Linkages: Replacing non-bridging oxygen atoms with sulfur to confer nuclease resistance and enhance plasma protein binding.
• 2'-O-Methyl (2'-OMe) & 2'-O-Methoxyethyl (2'-MOE): Sugar modifications providing sterical hindrance against RNases, suppressing innate immune activation, and increasing target mRNA affinity.
• Locked Nucleic Acids (LNA) & Fluoro (2'-F) Derivatives: Conformational locking of the ribose ring into a C3'-endo structure to yield ultra-high hybridization kinetics.

Targeted Delivery: GalNAc Conjugation

Targeted delivery to specific tissues remains a cornerstone of therapeutic success. For liver-targeted therapeutics (such as Inclisiran and Givosiran), Gentolex provides custom synthesis of N-Acetylgalactosamine (GalNAc) triantennary cluster conjugates:

• Asialoglycoprotein Receptor (ASGPR) Binding: High affinity ($K_d \sim 1-10 \text{ nM}$) binding to ASGPR abundantly expressed on parenchymal hepatocytes.
• Subcutaneous Route Optimization: Enables low-dose, long-acting subcutaneous administration (quarterly or bi-annually), significantly improving patient compliance in clinical trials.
• Custom Linker Chemistry: Cleavable or non-cleavable phosphoramidite-based linkers engineered for rapid endosomal release within liver cells.

Solid-Phase Oligo Synthesis & Downstream Purification

Transitioning from milligram discovery scale to multi-kilogram commercial batches requires robust manufacturing design:

• Automated Synthesis (SPOS): Phosphoramidite cycle optimization with real-time UV conductivity monitoring during detritylation and coupling.
• Cleavage & Deprotection: Controlled ammonium hydroxide / methylamine gas-phase protocols minimizing base modification or apurinic side products.
• Preparative Purification: Industrial-scale Ion-Pair Reversed-Phase (IP-RP-HPLC) or Strong Anion-Exchange (SAX-HPLC) coupled with ultrafiltration/diafiltration (UF/DF) for salt exchange and concentration.

Continuous Flow & Green Enzymatic Synthesis

Traditional phosphoramidite chemistry relies heavily on hazardous solvents (acetonitrile, dichloromethane). Gentolex is at the forefront of implementing continuous flow synthesis platforms and biocatalytic/enzymatic RNA synthesis protocols. Enzymatic template-independent polymerase technologies reduce toxic waste footprints by over 60% while expanding maximum achievable chain lengths ($>100\text{-mers}$) for complex guide RNAs and aptamers.

Extrahepatic Delivery Systems (CNS, Muscle, Lung)

While GalNAc conjugation efficiently targets liver tissues, expanding oligonucleotide utility requires extrahepatic delivery mechanisms. Gentolex is scaling the custom conjugation of lipophilic moieties (e.g., palmitic acid, cholesterol, $\alpha$-tocopherol), antibody-oligonucleotide conjugates (AOCs), and specialized peptide ligands for crossing the blood-brain barrier (BBB) to treat neurodegenerative diseases.

Advanced Backbone Engineering & Stereopurity

Standard phosphorothioate synthesis yields a complex stereoisomeric mixture of $R_p$ and $S_p$ configurations at each sulfur atom. Gentolex is integrating stereodefined coupling reagents into our commercial offerings. Control over absolute stereochemistry maximizes target knockdown efficacy, reduces off-target cytotoxicity, and stabilizes pharmacokinetic profiles in human clinical trials.