OTR-AC

OTR-AC (Ostarine O-Acetate) Research Standard

OTR-AC (Ostarine O-Acetate) is a synthetic acetate ester derivative of the nonsteroidal selective androgen receptor modulator (SARM) MK-2866 (Ostarine). The acetylation at the 2-hydroxy position of the arylpropionamide scaffold significantly alters the compound’s lipophilicity and metabolic profile compared to the non-esterified parent compound. In laboratory research, OTR-AC is utilized primarily as a tool for studying ester-modified arylpropionamide pharmacology, specifically focusing on enzymatic hydrolysis kinetics, comparative pharmacokinetic modeling, and high-fidelity analytical method development for forensic and pharmaceutical research.

Technical Specifications

Mechanism of Action (Research Context)

OTR-AC functions in experimental systems as a prodrug-like analog of MK-2866. Its research utility is defined by its pharmacokinetic evolution rather than a distinct receptor-binding mechanism independent of the parent compound.

• Ester Hydrolysis: The compound undergoes enzymatic hydrolysis in the presence of systemic esterases (found in plasma, liver, and intestinal tissues) to yield the parent molecule, MK-2866. Researchers use this conversion process to model the hydrolytic stability of ester-modified SARMs.

• Pharmacokinetic Profiling: The acetylation increases the lipophilicity of the molecule compared to the parent hydroxyl compound. This property is exploited in in vitro assays to study partition coefficients and membrane permeability dynamics.

• Receptor Pharmacology: Once hydrolyzed to the parent form, the molecule engages the androgen receptor (AR). Consequently, OTR-AC acts as a research benchmark for studying how structural modifications to an active ligand alter its metabolic delivery and temporal activation profile within AR-signaling pathways.

Research Applications

OTR-AC is a highly specific reagent utilized for analytical benchmarking and structure-activity relationship (SAR) investigations.

Primary fields of in vitro laboratory investigation include:

• Ester Hydrolysis Kinetics: Mapping the rate of conversion from OTR-AC to MK-2866 across various biological and synthetic esterase systems.

• Analytical Method Development: Establishing definitive MS fragmentation patterns, specifically monitoring the loss of the acetyl group (42 Da) to confirm identity in complex samples.

• Forensic and Toxicological Research: Providing a certified reference standard for the identification of arylpropionamide derivatives in chemical and pharmaceutical matrices.

• Comparative SAR Analysis: Evaluating the steric and electronic influence of the acetyl group on the overall binding affinity of the arylpropionamide scaffold.

Storage & Handling Guidelines

To maintain the chemical stability and experimental integrity of the ester:

• Long-Term Storage: Store at -20 °C in a dry environment to prevent premature hydrolytic degradation.

• Environmental Control: Protect strictly from light and moisture, as the ester bond is susceptible to cleavage under aqueous or basic conditions.

• Aseptic Technique: Keep containers tightly sealed when not in use. Use clean, non-reactive tools when weighing the material.

• Verification: Confirm molecular identity using mass spectrometry, looking for the molecular ion at m/z 431.1 and the characteristic fragment loss indicative of the acetate moiety.

Regulatory & Research Note

As an acetate ester of a compound listed on the WADA Prohibited List (MK-2866), OTR-AC is treated as an equivalent precursor in regulated research environments. Analytical investigators should maintain rigorous records and confirm compound identity, as incorrect structural assignments have been identified in non-technical supply chains.

Research Use Disclaimer

Research Use Only Disclaimer: This product is developed and distributed strictly as a Research Use Only (RUO) laboratory reference chemical intended exclusively for non-clinical analytical and scientific investigation. It is not an FDA-approved drug, medical treatment, dietary supplement, or food ingredient, and is strictly prohibited for human or animal consumption. Kimera Chems supplies this high-purity research material solely to qualified institutions and professional investigators for authorized laboratory research.