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| Other names | SK&F-89124; SKF-89124; SK&F89124; SKF89124; SK&F-89,124; SKF-89,124; SKF-89124A |
| Drug class | Dopamine receptor agonist; Dopamine D2-like receptor agonist |
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| Formula | C16H24N2O2 |
| Molar mass | 276.380 g·mol−1 |
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7-Hydroxyropinirole (developmental code name SK&F-89124 or SKF-89124) is a dopamine receptor agonist and active metabolite of the antiparkinsonian agent ropinirole (SK&F-101468). [1] [2] [3] It is a major metabolite of ropinirole in rats and dogs but a minor metabolite in mice, monkeys, and humans. [4] [3] In humans, 7-hydroxyropinirole accounts for less than 5% of a dose of ropinirole. [5] Its involvement in ropinirole's effects in humans is unknown. [5]
The drug is described as a highly potent and highly selective dopamine D2-like receptor agonist. [2] It has been reported to be 30-fold more potent than ropinirole as a dopamine D2 receptor agonist in vitro . [6] [7] However, ropinirole and 7-hydroxyropinirole were equipotent in terms of antiparkinsonian activity in rodents in vivo . [3]
7-Hydroxyropinirole is said to be rapidly glucuronidated in humans. [8] In addition, 7-hydroxyropinirole has reduced capacity to cross the blood–brain barrier than ropinirole. [9] This is due to its hydroxyl group, which increases it polarity and reduces its lipophilicity. [9] The log P of ropinirole is 2.46, whereas that of 7-hydroxyropinirole is 2.17. [9]
7-Hydroxyropinirole was first described in the scientific literature by 1983. [10] Subsequently, ropinirole was described in 1985. [1] [11] [12]
Before ROPI was first reported in 1985 [27], 7-hydroxyropinirole was identified as a highly potent dopamine agonist [28,29]. 7-Hydroxyropinirole has also been identified as a metabolite of ROPI in humans. [...] N,N-di-n-Propyldopamine is a lipophilic derivative of dopamine. By conversion of the monocyclic ring of N,N-di-n-propyldopamine to a bicyclic oxindole skeleton (bioisostere of phenol), 7-hydroxyropinirole was developed. Surprisingly, compared with that of N,N-di-npropyldopamine, the EC50 of 7-hydroxyropinirole for the dopamine D2 receptor (D2R) was greatly improved. ROPI does not have a 7-hydroxy group and its EC50 for D2R is higher than that of N,N-di-n-propyldopamine; nevertheless ROPI was ultimately selected as a clinical drug candidate.
In both animals and man, ropinirole was extensively metabolized. In the rat, the major metabolic pathway was via hydroxylation of the aromatic ring to form 7-hydroxy ropinirole. In mouse, monkey and man, the major pathway was via N-depropylation. The N-despropyl metabolite was metabolized further to form 7-hydroxy and carboxylic acid derivatives. Metabolites formed in all species were generally metabolized further by glucuronidation. 7-Hydroxy ropinirole is the only metabolite of ropinirole previously shown to possess significant dopamine agonist activity in vivo. [...] Brain extracts were shown to contain ropinirole and its 7-hydroxy metabolite (SK&F-89124 ; Figure 2). [...] In rat, the major metabolic pathway was via hydroxylation of the aromatic ring to form 7-hydroxy ropinirole (SK&F-89124). In mouse, monkey and man, the major pathway was via N-depropylation to form SK&F-104557, which was further metabolized, to a limited extent, to 7-hydroxy SK&F-104557 (SK&F-96990) and a carboxylic acid derivative of SK&F-104557 (SK&F-97930). Metabolites formed by either pathway were then generally metabolized further by glucuronidation in all species. SK&F-89124 is the only metabolite of ropinirole shown to possess significant dopamine agonist activity in an in vivo model of Parkinson's disease (Reavill et al., unpublished data).
The major metabolic pathway in humans is via N-depropylation;[55] the N-despropyl metabolite accounts for 35 to 40% of the oral dose in human urine. 7-hydroxy ropinirole, the only metabolite of ropinirole that is thought to have significant dopamine agonist activity in vivo, [55] accounts for less than 5% of the dose. The potential contribution of 7-hydroxy ropinirole to the clinical effects of the parent drug is unknown.
SK&F 101468 is hydroxylated vivo to form SK&F 89124, which is 30-fold more potent as a DA2 agonist (77); hence, although SK&F 101468 has intrinsic agonist activity at the DA2 receptor, being only two-fold less potent than dopamine as an inhibitor of adrenergic neurotransmission in the isolated rabbit ear artery (76), the majority of its in vivo activity may result from an active metabolite.
4-(2-Di-n-propylaminoethyl)-7-hydroxy-2-(3~)-indolone was found in the plasma of rats, dogs, and monkeys treated with 3. As a D2-agonist, 1 is 30 times more potent than 3 in in vitro studies.1.3 The metabolism of 3 to 1 may contribute to the in vivo pharmacologic effect of 3. In dogs and monkeys (Figs. 5 and 6) the concentrations of 1 are about 10-fold lower than those of 3 and decline in parallel with 3.
Most of the absorbed dose of ropinirole is cleared by metabolism in the liver, with only 10% of the administered dose being excreted as unchanged ropinirole.[35,42] The main metabolite of ropinirole (32 to 45% of the dose) is the N-despropyl metabolite SK&F 104557 (fig. 1).[35,43] The glucuronide of the metabolite SK&F 89124 and the carboxylic acid metabolite SK&F 97930 both represent about 10% of the administered dose. Neither of these metabolites is pharmacologically active; SK&F 89124 has some activity but is rapidly glucuronidated, and so it circulates at only low concentrations.[44] Therefore, all of the pharmacological activity achieved by orally administered ropinirole can be attributed to the parent molecule.
Three pairs of similar compounds collected from the dataset used in this paper are shown in Table 4. [...] The difference between SKF101468 and SKF89124 is shown in Fig. 13. The hydroxy group reduces logP and increases PSA, the influences of the hydroxy group makes logBB decrease.