Tadalafil as a Laboratory Reagent: Rigid Tetracyclic Scaffold and Storage Practice

Description

Tadalafil supplied for laboratory work is a synthetic small molecule of unusually rigid architecture, and that rigidity explains most of its behaviour on the bench — how it dissolves, how it crystallises and how it is best kept. The parameters below are the ones repeated on supplier certificates.

Molecular formula

C22H19N3O4

Formula weight

389.4 g/mol

CAS registry number

171596-29-5

Structural class

Tetracyclic hybrid — a tetrahydro-beta-carboline, that is an indole fused to a piperidine ring, condensed with a 2,5-diketopiperazine and carrying a 1,3-benzodioxole substituent.

Stereochemistry

Two defined stereocentres, in the 6R,12aR configuration. Diastereomers with an inverted centre carry their own registry numbers and are separate materials.

Physical form

Crystalline solid, white to off-white, as stated on the batch certificate.

Chromophore

Indole and benzodioxole rings, giving strong near-ultraviolet absorbance — the basis of routine assay by liquid chromatography with diode array detection.

The fused ring system leaves the molecule with two amide-type carbonyls in the diketopiperazine and no ionisable group of practical consequence. Nothing here is protonated or deprotonated within an ordinary buffer window, so adjusting pH is not a route to aqueous solubility. Reference-standard suppliers report solubility in dimethyl sulfoxide and dimethylformamide on the order of tens of milligrams per millilitre against negligible solubility in water, so stock solutions are prepared in an organic solvent and diluted into the aqueous phase immediately before use. See also our laboratory reagent: Sunifiram, czysta substancja chemiczna ≥ 99%. 1000.

That dilution step is where most bench problems appear. Rapid addition into aqueous buffer drives the compound out of solution as a fine precipitate that is easy to miss visually and fatal to quantitation. Slow addition with vigorous mixing, or a co-solvent system, keeps the material in a single phase. See also our laboratory reagent: L-DOPA ≥ 99%. Czysta substancja chemiczna bez wype.

Stability is not the difficult part. The diketopiperazine amide bonds resist hydrolysis under neutral conditions, and the solid is chemically robust when kept dry, sealed and out of light at the temperature named in the specification. Frozen organic stock solutions should be brought to room temperature and mixed before each withdrawal, since concentration gradients in a partly thawed vial are a common source of drift. Identity confirmation on receipt is straightforward: proton nuclear magnetic resonance against a reference spectrum, accurate-mass liquid chromatography with mass spectrometry, and chromatographic purity by area percent.

See also

• L-DOPA ≥ 99%. Czysta substancja chemiczna bez wypełniaczy!
• Sunifiram, czysta substancja chemiczna ≥ 99%. 1000mg.
• CBD / Cannabidiol / Cannabidiol, Krishals ≥ 99,85% 1000mg !
• Forskolina / Forksolin. Czystość ≥99% 1000mg.

Selected literature

Animal and in vitro studies indexed in PubMed; no human-use guidance is provided here.

• Greco EA Tadalafil and Steroid Hormones Interactions in Adipose, Bone and Prostate Tissues: Focus on Translational Perspectives 2022, International journal of molecular sciences. PMID 35457011
• Gong B Direct comparison of tadalafil with sildenafil for the treatment of erectile dysfunction: a systematic review and meta-analysis 2017, International urology and nephrology. PMID 28741090
• Sebastianelli A Tadalafil Alone or in Combination with Tamsulosin for the Management for LUTS/BPH and ED 2020, Current urology reports. PMID 33108544
• Mónica FZ Tadalafil for the treatment of benign prostatic hyperplasia 2019, Expert opinion on pharmacotherapy. PMID 30901259