63631-40-3Relevant academic research and scientific papers
Coumarinic acid-based cyclic prodrugs of opioid peptides that exhibit metabolic stability to peptidases and excellent cellular permeability
Gudmundsson, Olafur S.,Pauletti, Giovanni M.,Wang, Wei,Shan, Daxian,Zhang, Huijuan,Wang, Binghe,Borchardt, Ronald T.
, p. 7 - 15 (2007/10/03)
Purpose. To evaluate the cellular permeation characteristics and the chemical and enzymatic stability of coumarinic acid-based cyclic prodrugs 1 and 2 of the opioid peptides [Leu5]-enkephalin (H-Tyr-Gly-Gly-Phe-Leu-OH) and DADLE (H-Tyr-D-Ala-Gly-Phe-D-Leu-OH), respectively. Methods. The rates of conversion of the cyclic prodrugs 1 and 2 to [Leu5]-enkephalin and DADLE, respectively, in HBSS, pH 7.4 (Caco-2 cell transport buffer) and in various biological media having measurable esterase activity were determined by HPLC. The cell permeation characteristics of [Leu5]-enkephalin, DADLE and cyclic prodrugs 1 and 2 were measured using Caco-2 cell monolayers grown onto micropores membranes and monitored by HPLC. Results. In HBSS, pH 7.4, cyclic prodrugs 1 and 2 degraded chemically to intermediates that further degraded to [Leu5]-enkephalin and DADLE, respectively, in stoichiometric amounts. In 90% human plasma and rat liver homogenate, the disappearance of cyclic prodrugs 1 and 2 was significantly faster than in HBSS, pH 7.4. The half- lives in 90% human plasma and in rat liver homogenate were substantially longer after pretreatment with paraoxon, a known inhibitor of serine- dependent esterases. When applied to the AP side of a Caco-2 cell monolayer, cyclic prodrug 1 exhibited significantly greater stability against peptidase metabolism than did [Leu5]-enkephalin. Cyclic prodrug 2 and DADLE exhibited similar stability when applied to the AP side of the Caco-2 cell monolayer. Prodrug 1 was 665-fold more able to permeate the Caco-2 cell monolayers than was [Leu5]-enkephalin, in part because of its increased enzymatic stability. Prodrug 2 was shown to be approximately 31 fold more able to permeate a Caco- 2 cell monolayer than was DADLE. Conclusions. Cyclic prodrugs 1 and 2, prepared with the coumarinic acid promoiety, were substantially more able to permeate Caco-2 cell monolayers than were the corresponding opioid peptides. Prodrug 1 exhibited increased stability to peptidase metabolism compared to [Leu5]-enkephalin. In various biological media, the opioid peptides were released from the prodrugs by an esterase-catalyzed reaction, which is sensitive to paraoxon inhibition.
Phenylpropionic acid-based cyclic prodrugs of opioid peptides that exhibit metabolic stability to peptidases and excellent cellular permeation
Gudmundsson, Olafur S.,Nimkar, Kalpana,Gangwar, Sanjeev,Siahaan, Teruna,Borchardt, Ronald T.
, p. 16 - 23 (2007/10/03)
Purpose. To evaluate the cellular permeation characteristics and the chemical and enzymatic stability of phenylpropionic acid-based cyclic prodrugs 1 and 2 of opioid peptides [Leu5]-enkephalin (H-Tyr-Gly-Gly-Phe- Leu-OH) and DADLE (H-Tyr-D-Ala-Gly-Phe-D-Leu-OH), respectively. Methods. The rates of conversion of cyclic prodrugs 1 and 2 to [Leu5]-enkephalin and DADLE, respectively, in HBSS, pH 7.4 (Caco-2 cell transport buffer) and in various biological media having measurable esterase activity were determined by HPLC. The cell permeation characteristics of [Leu5]-enkephalin, DADLE, and cyclic prodrugs 1 and 2 were measured using Caco-2 cell monolayers grown onto microporus membranes and monitored by HPLC. Results. In HBSS, pH 7.4, cyclic prodrugs 1 and 2 degraded to [Leu5]-enkephalin and DADLE, respectively, in stoichiometric amounts. In 90% human plasma, the rates of disappearance of cyclic prodrugs 1 and 2 were slightly faster than in HBSS, pH 7.4. These accelerated rates of disappearance in 90% human plasma could be reduced to the rates observed in HBSS, pH 7.4, by pretreatment of the plasma with paraoxon, a known inhibitor of serine-dependent esterases. In homogenates of Caco-2 cells and rat liver, accelerated rates of disappearance of cyclic prodrugs 1 and 2 were not observed. When applied to the AP side of a Caco-2 cell monolayer, cyclic prodrug 1 exhibited significantly greater stability against peptidase metabolism than did [Leu5]-enkephalin. Cyclic prodrug 2 find DADLE exhibited stability similar to prodrug 1 when applied to the AP side of the Caco-2 cell monolayers. Prodrug 1 was 1680 fold more able to permeate the Caco-2 cell monolayers than was [Leu5]-enkephalin, in part because of its increased enzymatic stability. Prodrug 2 was shown to be approximately 77 fold more able to permeate a Caco-2 cell monolayer than was DADLE. Conclusions. Cyclic prodrugs 1 and 2, prepared with the phenylpropionic acid promoiety, were substantially more able to permeate Caco-2 cell monolayers than were the corresponding opioid peptides. Prodrug 1 exhibited increased stability to peptidase metabolism compared to [Leu5]- enkephalin. In 90% human plasma but not in Caco-2 cell and rat liver homogenates, the opioid peptides were released from the cyclic prodrugs by an esterase-catalyzed reaction that is sensitive to paraoxon inhibition. However, the rate of this bioconversion appears to be extremely slow.
Acyloxyalkoxy-based cyclic prodrugs of opioid peptides: Evaluation of the chemical and enzymatic stability as well as their transport properties across Caco-2 cell monolayers
Bak, Annette,Gudmundsson, Olafur S.,Friis, Gitte J.,Siahaan, Teruna J.,Borchardt, Ronald T.
, p. 24 - 29 (2007/10/03)
Purpose. To evaluate the chemical and enzymatic stability, as well as the cellular permeation characteristics, of the acyloxyalkoxy-based cyclic prodrugs 1 and 2 of the opioid peptides [Leu5]-enkephalin (H-Tyr-Gly-Gly- Phe-Leu-OH) and DADLE (H-Tyr-D-Ala-Gly-Phe-D-Leu-OH), respectively. Methods. The rates of conversion of 1 and 2 to [Leu5]-enkephalin and DADLE, respectively, were measured by HPLC in HBSS, pH = 7.4, and in various biological media (e.g., human plasma and Caco-2 cell and rat liver homogenates) having measurable esterase activity. The cellular permeation and metabolism characteristics of [Leu5]-enkephalin, DADLE and the cyclic prodrugs 1 and 2 were measured using Caco-2 cell monolayers grown onto microporous membranes and monitored by HPLC. Results. Cyclic prodrugs 1 and 2 degraded slowly but stoichiometrically to [Leu5]-enkephalin and DADLE, respectively, in HBSS, pH = 7.4. In homogenates of Caco-2 cells and rat liver, as well as 90% human plasma, the rates of disappearance of the cyclic prodrugs were significantly faster than in HBSS. The stabilities of the cyclic prodrugs 1 and 2 were increased significantly in 90% human plasma and Caco-2 cell homogenates when paraoxon, a potent inhibitor of serine-dependent esterases, was included in the incubation mixtures. A similar stabilizing effect of paraoxon was not observed in 50% rat liver homogenates, but was observed in 10% homogenates of rat liver. When applied to the AP side of a Caco-2 cell monolayer, DADLE and cyclic prodrugs 1 and 2 exhibited significantly greater stability than [Leu5]-enkephalin. Based on their physicochemical properties (i.e., lipophilicity), cyclic prodrugs 1 and 2 should have exhibited high permeation across Caco-2 cell monolayers. Surprisingly, the AP-to-BL apparent permeability coefficients (P(App)) for cyclic prodrugs 1 and 2 across Caco-2 cell monolayers were significantly lower than the P(App) value determined for the metabolically stable opioid peptide DADLE. When the P(App) values for cyclic prodrugs 1 and 2 crossing Caco-2 cell monolayers in the BL-to-AP direction were determined, they were shown to be 36 and 52 times greater, respectively, than the AP-to-BL values. Conclusions. Cyclic prodrugs 1 and 2, prepared with an acyloxyalkoxy promoiety, were shown to degrade in biological media (e.g., 90% human plasma) via an esterase-catalyzed pathway. The degradation of cyclic prodrug 1, which contained an ester formed with an L-amino acid, degraded more rapidly in esterase-containing media than did prodrug 2, which contained an ester formed with a D-amino acid. Cyclic prodrugs 1 and 2 showed very low AP-to-BL Caco-2 cell permeability, which did not correlate with their lipophilicities. These low AP-to-BL permeabilities result because of their substrate activity for apically polarized efflux systems.
Synthesis and antinociceptive activity of [D-Ala2]Leu-enkephalin derivatives conjugated with the adamantane moiety
Kitagawa, Kouki,Mizobuchi, Noriko,Hama, Teruo,Hibi, Tohru,Konishi, Ryoji,Futaki, Shiroh
, p. 1782 - 1787 (2007/10/03)
Based on the physicochemical and pharmacological properties of drugs having an adamantane skeleton, an adamantane-based moiety was evaluated as a drug carrier for poorly absorbed compounds, including peptides, active towards the central nervous system (CNS). Seven [D-Ala2]Leu-enkephalin derivatives conjugated with an adamantane-based moiety at the C-terminus or N-terminus were prepared by the solution-phase method and their biological activities were examined. The compounds derivatized at the C-terminus through an ester or amide linkage were much more lipophilic than the parent peptide and exhibited moderate in vitro opioid activity (guinea-pig ileum assay). Among them, four derivatives (1, 2, 4, 5), exhibited significant antinociceptive effects in an in vivo assay (mouse tail-pressure test) after subcutaneous administration. This result suggests that the introduction of the lipophilic adamantane moiety into [D-Ala2]Leu- enkephalin would improve the permeation of the poorly absorbed parent peptide through the blood-brain-barrier (BBB) without loss of antinociceptive effect.
Coumarin-based prodrugs 2. Synthesis and bioreversibility studies of an esterase-sensitive cyclic prodrug of DADLE, an opioid peptide
Wang, Binghe,Wang, Wei,Zhang, Huijuan,Shan, Daxian,Smith, Terrill D.
, p. 2823 - 2826 (2007/10/03)
A coumarin-based esterase-sensitive cyclic prodrug of an opioid peptide, DADLE, was prepared. The cyclic prodrug quickly released (t( 1/4 ) = 761 min) its original peptide, DADLE, upon esterase catalyzed hydrolysis. Such a system can be used for the preparation of cyclic prodrugs of other biologically active peptides aimed at improving their bioavailability.
Synthesis of 2>Leu-enkephalin and 2,D-Leu5>Leu-enkephalin with High Specific Tritiated Activity in the Leucine Residue
Hasegawa, Hiroshi,Shinohara, Yoshihiko,Baba, Shigeo
, p. 2641 - 2644 (2007/10/02)
2>Leu-enkephalin and 2,D-Leu5>Leu-enkephalin (DADLE) labelled with tritium in the leucine residue have been prepared.Synthesis of the precursor peptides, 2,4,5-didehydro-L-Leu5>Leu-enkephalin and 2,4,5-didehydro-D-Leu5>Leu-enkephalin, was carried out by solid-phase synthesis using Fmoc amino acid derivatives, followed by diastereoisomeric separation on HPLC.These peptides were tritiated catalytically to yield DALE with a specific activity of 5.35 TBq mmol-1 and DADLE with that of 5.43 TBq mmol-1, respectively.The distribution of tritium label was investigated by HPLC with a radioisotopic detector following acidic hydrolysis, which confirmed that the tritium label in both labelled peptides was exclusively located at the leucine residue.
A photoaffinity reagent to label the opiate receptors of guinea pig ileum and mouse vas deferens
Fujioka,Matsunaga,Nakayama,Kanaoka,Hayashi,Kangawa,Matsuo
, p. 836 - 840 (2007/10/02)
An enkephalin derivative, [D-Ala2,Leu5]enkephalin N-[(2-nitro-4-azidophenyl)amino]ethylamide, has been synthesized as a photoaffinity label for the opiate receptor. This compound retains the full biological activity of [D-Ala2,Leu5]enkephalin in guinea pig ileum and mouse vas deferens tests with IC50 values of 4.4 and 2.6 nM, respectively, and inhibits the binding of [3H]naloxone to rat brain membrane preparation with an IC50 value of 2.5 nM. Photolysis of a muscle strip of the guinea pig ileum or of the mouse vas deferens in the presence of the peptide derivative caused irreversible inhibition of electrically stimulated contractions with high efficiencies (80 and 66%, respectively), while the inhibitory effect in the dark was fully reversed by washing. This irreversible inhibition during photolysis was completely prevented by the presence of [D-Ala2,Leu5]enkephalin. These results demonstrate that {D-Ala2,Leu5]-enkephalin N-[(2-nitro-4-azidophenyl)amino]ethylamide is a prominent candidate as a photoaffinity label for the opiate receptor.
Phosphinyl- and Phosphinothioylamino Acids and Peptides. VI. The Protection of the Hydroxyl Function in the Tyrosine Side-chain by the Dimethylphosphinothioyl Group
Ueki, Masaaki,Inazu, Toshiyuki
, p. 204 - 207 (2007/10/02)
The use of the dimethylphosphinothioyl (Mpt) group for the protection of the hydroxyl function in the tyrosine side-chain was studied. N,O-Bis(Mpt)tyrosine was obtained directly by a Schotten-Baumann-type reaction of Mpt-Cl with tyrosine. The O-Mpt group was stable under acidic conditions, and it could be removed easily by alkaline hydrolysis or ester-exchange reaction. The usefulness of this new protecting group for the peptide synthesis was shown in the solid-phase synthesis of 2,L-Leu5>-enkephalin(H-L-Tyr-D-Ala-Gly-L-Phe-L-Leu-OH) and its N-allyl derivative.
