{"id":536,"date":"2022-10-21T18:04:15","date_gmt":"2022-10-21T16:04:15","guid":{"rendered":"https:\/\/modafinil.pl\/sklep\/viagra-tadalafil-purity-%e2%89%a5-99-1000mg\/"},"modified":"2026-10-03T06:11:57","modified_gmt":"2026-10-03T04:11:57","slug":"tadalafil-2","status":"publish","type":"product","link":"https:\/\/modafinil.pl\/en\/sklep\/tadalafil-2\/","title":{"rendered":"Tadalafil (CAS 171596-29-5) \u2014 laboratory reagent 1000 mg, purity \u2265 99%"},"content":{"rendered":"

(2R,8R)-2-(1,3-benzodioxol-5-yl)-6-methyl-3,6,17-triazatetracyclo[8.7.0.0\u00b3,\u2078.0\u00b9\u00b9,\u00b9\u2076]heptadeca-1(10),11,13,15-tetraene-4,7-dione<\/strong>, more widely known by its common name tadalafil<\/strong>, crystalline powder, 1000 mg pack. Material intended exclusively for laboratory and analytical in vitro research<\/strong>. This product is not intended for human or animal consumption<\/strong>; it is not a medicinal product, food supplement, foodstuff or cosmetic.<\/p>\n

Three distinct entities that must not be confused<\/h2>\n

For this molecule, separating the layers is just as important as for any other substance in our catalogue that is at the same time the active substance of prescription-only medicines<\/strong>. Three contexts, three entirely different legal statuses:<\/p>\n\n\n\n\n\n\n\n
Separating the layers: substance \u2014 medicinal product \u2014 reagent<\/caption>\n
Entity<\/th>\nWhat it is<\/th>\nWhat it concerns<\/th>\n<\/tr>\n<\/thead>\n
Chemical substance
tadalafil, CAS 171596-29-5<\/th>\n		A chemical concept \u2014 a molecule of defined structure, with two configured stereogenic centres (2R,8R). In itself it is neither a medicine nor a reagent; its status is conferred only by the form in which it has been manufactured and authorised.<\/td>\nchemistry, substance registers<\/td>\n<\/tr>\n
Medicinal product
e.g. Cialis, Adcirca, Entadfi, Opsynvi<\/th>\n		Pharmaceutical preparations with various registered indications (erectile dysfunction, pulmonary arterial hypertension, benign prostatic hyperplasia). A defined pharmaceutical form and strength, manufacture under GMP, registration dossier, safety monitoring. In Poland dispensed only on prescription.<\/strong><\/td>\nit is this entity that the clinical studies involving humans concern<\/strong><\/td>\n<\/tr>\n
Chemical reagent
the material offered here<\/th>\n		Material for laboratory and analytical work. It does not have, and cannot have, any authorisation for use in humans or animals<\/strong> \u2014 it has no pharmaceutical form and no medicinal product documentation.<\/td>\nanalytics, chemistry, reference standards<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The consequence is unambiguous.<\/strong> The research results referred to later on this page were obtained exclusively with the registered medicinal product<\/strong>, in clinical and pharmacokinetic studies involving humans. None of these studies was conducted with an analytical reagent<\/strong>, and none of these results transfers to the material offered. The reagent is not a form in which the substance has ever been administered to humans, and it cannot be used in that way.<\/p>\n

Reagent identification sheet<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Registry data and identifiers \u2014 tadalafil<\/caption>\n
Systematic name (IUPAC)<\/th>\n(2R,8R)-2-(1,3-benzodioxol-5-yl)-6-methyl-3,6,17-triazatetracyclo[8.7.0.0\u00b3,\u2078.0\u00b9\u00b9,\u00b9\u2076]heptadeca-1(10),11,13,15-tetraene-4,7-dione<\/td>\n<\/tr>\n
Common name<\/th>\ntadalafil<\/td>\n<\/tr>\n
Development codes<\/th>\nIC-351 (ICOS Corporation), LY-450190 (Eli Lilly)<\/td>\n<\/tr>\n
CAS number<\/th>\n171596-29-5<\/td>\n<\/tr>\n
Molecular formula<\/th>\nC22<\/sub>H19<\/sub>N3<\/sub>O4<\/sub><\/td>\n<\/tr>\n
Molar mass<\/th>\n389.4 g\u00b7mol\u22121<\/sup><\/td>\n<\/tr>\n
Monoisotopic mass<\/th>\n389.1376 Da<\/td>\n<\/tr>\n
Melting point<\/th>\n301.5\u00b0C<\/td>\n<\/tr>\n
InChIKey<\/th>\nWOXKDUGGOYFFRN-IIBYNOLFSA-N<\/td>\n<\/tr>\n
SMILES<\/th>\nCN1CC(=O)N2C(C1=O)CC3=C(C2C4=CC5=C(C=C4)OCO5)NC6=CC=CC=C36<\/td>\n<\/tr>\n
PubChem CID<\/th>\n110635<\/a><\/td>\n<\/tr>\n
ChEMBL<\/th>\nCHEMBL3665030<\/td>\n<\/tr>\n
UNII (FDA)<\/th>\n742SXX0ICT<\/td>\n<\/tr>\n
ChEBI<\/th>\nCHEBI:71940<\/td>\n<\/tr>\n
Form<\/th>\ncrystalline powder, white to off-white<\/td>\n<\/tr>\n
Purity<\/th>\n\u2265 99%<\/td>\n<\/tr>\n
Intended use<\/th>\nresearch reagent \u2014 not for human or animal consumption<\/strong><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Origins of the molecule: a different route to the same enzyme<\/h2>\n

Tadalafil is not a modification of a molecule that was already on the market \u2014 it is a structurally distinct route<\/strong> to inhibiting the same enzyme that other research teams had already been working on. The core of the molecule is a tetracyclic pyrazinopyridoindole system<\/strong> \u2014 a distant relative of the \u03b2-carboline scaffold, additionally closed by a diketopiperazine ring bearing a 1,3-benzodioxole substituent. This is an entirely different scaffold from that of the first registered inhibitor of this enzyme class, which is based on a pyrazolopyrimidinone core \u2014 Sildenafil (CAS 171599-83-0)<\/a> is a good reference point here: the same enzymatic target, a completely different ring architecture.<\/p>\n

The family of tetracyclic pyridoindole derivatives<\/h3>\n

The same core \u2014 a tetrahydro-\u03b2-carboline system fused with a diketopiperazine ring \u2014 was studied independently by various teams designing inhibitors of the same enzyme. Liu et al. described a series of substituted acetates based on a related imidazo-pyrido-indole system as a new class of vasodilating compounds [5<\/a>], and Ahmed et al. designed and synthesised functionalised tetrahydro-\u03b2-carboline derivatives as new inhibitors of the same enzymatic target [7<\/a>]. The most recent of these papers, Mieczkowski et al. (2021), extended the same family with flexible analogues based on a diketopiperazine moiety, with solved crystal structures and a biological activity profile [10<\/a>].<\/p>\n

From a biotechnology laboratory to a joint venture<\/h3>\n

The molecule was isolated in the laboratories of the biotechnology company ICOS Corporation (Bothell, Washington State, USA) \u2014 hence the first development code, IC-351. In 1998 ICOS entered into a joint venture with Eli Lilly and Company (Lilly ICOS LLC) for the further development and commercialisation of the compound \u2014 from that point on, a second code, LY-450190, reflecting Lilly’s internal designation, appears in pharmacokinetic publications. In 2007 Eli Lilly acquired ICOS Corporation in full, consolidating the rights to the molecule in a single owner.<\/p>\n

After patent expiry: a shift towards analytics<\/h3>\n

Patent protection expired in the major jurisdictions in 2017\u20132018. Since then the centre of gravity of new literature has clearly shifted from clinical pharmacology towards analytics and quality control<\/strong> \u2014 HPLC, NMR and GC-MS methods for confirming identity and purity and for detecting this substance in unregistered preparations. For a laboratory working with this reagent this is of practical importance: the most recent, best-documented analytical methods now come mainly from this stream, not from the original registration work of twenty years ago.<\/p>\n

Timeline<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n
Timeline: the origin and dissemination of the molecule<\/caption>\n
1998<\/th>\nformation of the Lilly ICOS LLC joint venture to develop the compound discovered in the laboratories of ICOS Corporation<\/td>\n<\/tr>\n
2002\u20132003<\/th>\nregistration as a medicinal product in Europe and then in the United States; first large clinical studies of efficacy and tolerability [2<\/a>] and cross-sectional pharmacological profiles of the substance [1<\/a>][3<\/a>]<\/td>\n<\/tr>\n
2006<\/th>\nclinical pharmacokinetic studies of the registered medicinal product in healthy volunteers [4<\/a>]<\/td>\n<\/tr>\n
2007<\/th>\nEli Lilly acquires ICOS Corporation in full<\/td>\n<\/tr>\n
2009<\/th>\nextension of the medicinal product registrations to further indications: pulmonary arterial hypertension and symptoms of benign prostatic hyperplasia<\/td>\n<\/tr>\n
2010<\/th>\nidentification of the trans-diastereomer of tadalafil in counterfeit products and assessment of the optical purity of the stereoisomers by chromatographic methods [6<\/a>]<\/td>\n<\/tr>\n
2014\u20132015<\/th>\nstability-indicating RP-HPLC method for combination preparations [9<\/a>] and a quantitative 1<\/sup>H-NMR method for determining tadalafil in bulk material and tablets [8<\/a>]<\/td>\n<\/tr>\n
2017\u20132018<\/th>\nexpiry of patent protection in the major jurisdictions; availability of generic equivalents<\/td>\n<\/tr>\n
2020<\/th>\nGC-MS method for the screening detection of inhibitors of this enzyme class in unregistered preparations [11<\/a>]<\/td>\n<\/tr>\n
2024<\/th>\nmost recent indexed stability-indicating RP-HPLC-DAD method for the simultaneous determination of tadalafil in a synthetic mixture [12<\/a>]<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Chemistry: two stereogenic centres and the trans diastereomer<\/h2>\n

Cis versus trans \u2014 why this is not a pair of enantiomers<\/h3>\n

The molecule has two stereogenic centres<\/strong>, designated in the systematic name as (2R,8R) \u2014 one at the carbon linking the benzodioxole ring to the tetracyclic core, the other at the ring junction with the indole. The registered configuration is the cis<\/em> junction of these two centres. The counterpart with a trans<\/em> junction \u2014 i.e. a diastereomer, not an enantiomer \u2014 is a separate compound with different physicochemical properties and a different chromatographic retention profile. Venhuis et al. identified (\u2013)-trans-tadalafil alongside tadalafil and sildenafil in counterfeit commercial preparations and assessed the optical purity of the tadalafil stereoisomers by chromatographic methods [6<\/a>] \u2014 the presence of the trans diastereomer is one of the markers distinguishing a synthesis with poorer stereochemical control.<\/p>\n

For the laboratory this has a practical consequence: a total determination alone (e.g. LC-UV without separation of stereoisomers) does not confirm which diastereomer is present in the sample<\/strong>. Confirmation of configurational identity requires a stereochemistry-sensitive method \u2014 chiral-phase chromatography, NMR spectroscopy or comparison with a reference material of confirmed (2R,8R) configuration.<\/p>\n

Physicochemical characteristics<\/h3>\n\n\n\n\n\n\n\n\n\n\n\n
Computed descriptors and their analytical significance<\/caption>\n
Parameter<\/th>\nValue<\/th>\nWhat follows from it<\/th>\n<\/tr>\n<\/thead>\n
Partition coefficient (XLogP)<\/th>\n\u2248 2.3<\/td>\nmoderate lipophilicity \u2014 elutes in the middle-to-late part of the RP-HPLC gradient<\/td>\n<\/tr>\n
Topological polar surface area<\/th>\n74.9 \u00c52<\/sup><\/td>\ntwo amide carbonyl groups and the methylenedioxy ring raise the number of hydrogen bond acceptors<\/td>\n<\/tr>\n
Hydrogen bond donors<\/th>\n1<\/td>\nN\u2013H in the indole ring<\/td>\n<\/tr>\n
Hydrogen bond acceptors<\/th>\n4<\/td>\ntwo amide carbonyl groups and the two oxygen atoms of the benzodioxole ring<\/td>\n<\/tr>\n
Rotatable bonds<\/th>\n1<\/td>\nrigid tetracyclic system \u2014 little conformational freedom despite the high molecular mass<\/td>\n<\/tr>\n
Melting point<\/th>\n301.5\u00b0C<\/td>\nhigh for an organic compound of this size \u2014 a consequence of the rigid, highly fused ring scaffold<\/td>\n<\/tr>\n
Solubility<\/th>\ngood in DMSO; limited in water<\/td>\nprepare stock solutions in an organic solvent<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Why one molecule has several names and codes<\/h2>\n

In the literature and databases, several designations are used for the same molecule with CAS number 171596-29-5, apart from the trade names of the registered medicinal preparations (listed only in the table above):<\/p>\n