- Theoretical design of prodrug-enhancer combination based on a skin diffusion model: Prediction of permeation of acyclovir prodrugs treated with 1-geranylazacycloheptan-2-one
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Purpose. A theoretical design of percutaneous penetration enhancement in which prodrug derivation and enhancer application are combined is proposed based on the skin diffusion model and it is experimentally verified. Methods. Employing acyclovir as a model drug, the hypothesis was tested by synthesis of its prodrugs and evaluation of their in vitro permeation in the rat skin, with or without a penetration enhancer, 1-geranylazacycloheptan-2-one (GACH). Results. Among five acyclovir prodrugs, those with higher lipophilicities (propionate, butyrate, valerate, and hexanoate prodrugs) showed greater skin penetration than those of hydrophilic prodrugs (acetate), when administered in combination with GACH. Furthermore, the observed enhancement ratios were in good agreement with those predicted by theoretical consideration. Conclusions. Thus, skin permeation of prodrugs applied with an enhancer can be predicted and optimized by model analysis.
- Bando, Hiroto,Takagi, Toshihide,Yamashita, Fumiyoshi,Takakura, Yoshinobu,Hashida, Mitsuru
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- Some aspects on acyclonucleoside synthesis
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An acyclonucleoside synthesis was investigated on the regioselective introduction of an acyclochain. We found that iodotrimethylsilane catalyzed the reaction of acyclochain introduction as well as its migration from S2 to N1 of 2-thiothymine and from N7 to N9 position of guanine. By taking the findings into account, several acyclonucleosides were synthesized in a simple one-pot procedure.
- Ubasawa, Masaru,Takashima, Hideaki,Sekiya, Kouichi
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- New green synthesis and formulations of acyclovir prodrugs
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Different green synthesis of alkyl esters of acyclovir (acyclovir prodrugs) is described. Hexanoic, decanoic, dodecanoic and tetradecanoic acyclovir esters were synthesized reacting acyclovir and the respective acid anhydride in dimethyl sulfoxide (DMSO), in solvents from renewable sources and without solvent (T=30 °C). Yields in prodrugs after 10 min of reaction were >95% using DMSO as solvent. The purification methodology was very simple, shorter and greener than previously described. The biosolvent, N,N-dimethylamide of decanoic acid, let us to obtain >95% yield at 24 h. This oily biosolvent is not dermotoxic and the reaction crude can directly be used in topic formulations. Syntheses without solvent proceeded successfully for acyclovir esters. Indeed, dodecanoate and tetradecanoate yielding >98% conversion of reactants in 30 min. In spite of requiring mild temperature (65 °C), substrate molar ratios were lowered to 1 : 1, thus conducing to a more efficient use of raw materials. The synthetic procedures were scaled up to a 300 g batch (yield 98-99% isolated ester). These esters can be used as acyclovir prodrugs in topic formulations. The esters release from an oil/water micro-emulsion and a hydrogel formulation were tested with good results.
- De Regil-Hernandez, Ruben,Martinez-Lagos, Fernando,Rodriguez-Bayon, Amalia,Sinisterra, Jose-Vicente
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- Transport of acyclovir ester prodrugs through rabbit cornea and SIRC-rabbit corneal epithelial cell line
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The purpose of this study is to assess the permeability of acyclovir (ACV) prodrugs through the rabbit corneal cell line (SIRC) as well as the cornea, and characterize the SIRC cell line for transport and metabolism studies of ester prodrugs. Prodrug derivatization of an acycloguanosine antiviral agent, acyclovir, was employed to improve its permeability across the cornea. New Zealand albino rabbits were used as an animal model for corneal studies. The SIRC cell line grown on polyester membranes was used for transport of these prodrugs. SIRC cells grown on the membrane support for 10 days developed four to six layers of epithelial cells, and this is comparable to the normal rabbit corneal epithelial layer. Transport experiments were conducted across the rabbit cornea and confluent SIRC cells using side-by-side diffusion-cell apparatus. Enzymatic hydrolysis of these compounds was evaluated in SIRC cell lysates. Appropriate reversed phase HPLC method(s) were employed for quantitation of both the prodrug and ACV simultaneously. Corneal permeabilities of some of these prodrugs (Malonyl ACV and Acetyl ACV) were higher relative to ACV. The SIRC cell line permeability values of all the prodrugs were higher compared to that of the intact cornea. The total amount of ACV-prodrugs transported, i.e., unhydrolyzed prodrugs and regenerated ACV, across the SIRC cell line was more relative to ACV. Hydrolytic studies in the SIRC cell line homogenate demonstrated the bioreversion potential of the prodrugs and the presence of enzymes, particularly the cholinesterase in the SIRC cell line. It may be concluded that the SIRC cell line is leakier compared to the cornea. Keeping in mind the limitations, the SIRC cell line after further characterization may be used for transport and metabolism studies of ester prodrugs.
- Tak, Rahul V.,Pal, Dhananjay,Gao, Hongwu,Dey, Surajit,Mitra, Ashim K.
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- Chemoselective N-Deacetylation of Protected Nucleosides and Nucleotides Promoted by Schwartz's Reagent
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Protection and deprotection strategies involving the N-acetyl group are widely utilized in nucleoside and nucleotide chemistry. Herein, we present a mild and selective N-deacetylation methodology, applicable to purine and pyrimidine nucleosides, by means of Schwartz's reagent, compatible with most of the common protecting groups used in nucleoside chemistry.
- Ferrari, Valentina,Serpi, Michaela,McGuigan, Christopher,Pertusati, Fabrizio
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- Synthesis of acyclic nucleoside analogues based on 1,2,4-triazolo[1,5-a] pyrimidin-7-ones by one-step Vorbrüggen glycosylation
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New acyclovir analogues were obtained by reaction of 1,2,4-triazolo[1,5-a] pyrimidin-7-ones 4a-i with (2-acetoxyethoxy)methyl acetate 5 in the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf) as catalyst (Vorbrüggen procedure). Coupling betwe
- Khalymbadzha, Igor A.,Shestakova, Tatyana S.,Subbotina, Julia O.,Eltsov, Oleg S.,Musikhina, Alexandra A.,Rusinov, Vladimir L.,Chupakhin, Oleg N.,Karpenko, Inna L.,Jasko, Maxim V.,Kukhanova, Marina K.,Deev, Sergey L.
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p. 1298 - 1305
(2014/02/14)
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- Novel water-soluble prodrugs of acyclovir cleavable by the dipeptidyl-peptidase IV (DPP IV/CD26) enzyme
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We herein report for the first time the successful use of the dipeptidyl peptidase IV (DPPIV/CD26) prodrug approach to guanine derivatives such as the antiviral acyclovir (ACV). The solution- and solid-phase synthesis of the tetrapeptide amide prodrug 3 and the tripeptide ester conjugate 4 of acyclovir are reported. The synthesis of the demanding tetrapeptide amide prodrug of ACV 3 was first established in solution and successfully transferred onto solid support by using Ellman's dihydropyran (DHP) resin. In contrast with the valyl ester prodrug (valacyclovir, VACV), the tetrapeptide amide prodrug 3 and the tripeptide ester conjugate 4 of ACV proved fully stable in PBS. Both prodrugs converted to VACV (for 4) or ACV (for 3) upon exposure to purified DPPIV/CD26 or human or bovine serum. Vildagliptin, a potent inhibitor of DPPIV/CD26 efficiently inhibited the DPPIV/CD26-catalysed hydrolysis reaction. Both amide and ester prodrugs of ACV showed pronounced anti-herpetic activity in cell culture and significantly improved the water solubility in comparison with the parent drug.
- Diez-Torrubia, Alberto,Cabrera, Silvia,De Castro, Sonia,García-Aparicio, Carlos,Mulder, Gwenn,De Meester, Ingrid,Camarasa, María-José,Balzarini, Jan,Velázquez, Sonsoles
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p. 456 - 468
(2013/11/19)
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- New potential prodrugs of aciclovir using calix[4]arene as a lipophilic carrier: Synthesis and drug-release studies at the air-water interface
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Two tetra-p-tert-butyl-calix[4]arene species bearing one or two anti-HSV aciclovir units tethered via carbodiester linkages at the lower rim were synthesized as possible antiviral prodrugs. The amphiphilic properties of these derivatives were studied usin
- Sautrey, Guillaume,Clarot, Igor,Rogalska, Ewa,Regnouf-De-Vains, Jean-Bernard
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p. 2060 - 2069
(2013/02/25)
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- Real-time measurements of protein dynamics using fluorescence activation-coupled protein labeling method
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We present a fluorescence activation-coupled protein labeling (FAPL) method, which employs small-molecular probes that exhibit almost no basal fluorescence but acquire strong fluorescence upon covalent binding to tag-proteins. This method enables real-time imaging of protein labeling without any washout process and is uniquely suitable for real-time imaging of protein dynamics on the cell surface. We applied this method to address the spatiotemporal dynamics of the EGF receptor during cell migration.
- Komatsu, Toru,Johnsson, Kai,Okuno, Hiroyuki,Bito, Haruhiko,Inoue, Takanari,Nagano, Tetsuo,Urano, Yasuteru
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supporting information; experimental part
p. 6745 - 6751
(2011/06/22)
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- PRODRUGS CLEAVABLE BY CD26
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The present invention provides a new prodrug technology and new prodrugs in order to increase the solubility, to modulate plasma protein binding or to enhance the biovailability of a drug. In the present invention the prodrugs are conjugates of a therapeutic compound and a peptide (eg tetrapeptide or hexapeptide) wherein the conjugate is cleavable by dipeptidyl-peptidases, more preferably by CD26, also known as DPPIV (dipeptidyl aminodipeptidase IV). The present invention furthermore provides a method of producing said prodrugs, to enhance brain and lymphatic delivery of drugs and/or to extend drug half-lives in plasma.
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Page/Page column 67
(2008/06/13)
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- NMR spectral data for acyclovir prodrugs
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Both 1H NMR and 13C NMR spectra were assigned to a series of acyclovir ester and amide prodrugs. Assignments were based on spectral comparison with compounds of similar structure. Copyright
- Gao, Hongwu,Mitra, Ashim K.
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p. 687 - 689
(2007/10/03)
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- Process for the synthesis of 9-(2-hydroxyethoxy methyl) guanine
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A process for the synthesis of 9-(2-hydroxyethoxy methyl) guanine in which guanine, or its salts, is reacted with 2-4 moles of hexamethyldisilazane, in the presence of an aprotic solvent and of ammonium sulfate. Thereafter, the trimethylsilyl derivative, without being isolated, is reacted with a stoichiometric quantity of an acyloxyethoxy methyl halide and hydrolyzed with aqueous sodium acetate or sodium hydroxyde to give 9-(2-hydroxyethyoxy methyl) guanine.
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- Preparation of N-9 substituted guanine compounds
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The invention relates to efficient and selective processes for the synthesis of the antiviral N-9 substituted guanine compounds acyclovir and ganciclovir.
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- Process for the synthesis of 9(2-hydroxyethoxy methyl) guanine
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The subject of the present invention is a new process for the synthesis of 9-(2-hydroxyethoxy methyl) guanine (acyclovir) (I), carried out starting from guanine, without intermediate isolation.
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- A novel palladium-catalyzed deoxygenation of guanine O6-arenesulfonates. A practicable synthesis of 2-aminopurine nucleosides and related analogs
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A simple synthesis of 2-aminopurine nucleosides and related derivatives has been accomplished from the corresponding guanine O6-arenesulfonates. Studies towards the determination of optimum conditions for reduction and regioselectivity control are also reported.
- Stimac,Muhic,Kobe
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p. 625 - 636
(2007/10/02)
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- Process for preparing purine derivates
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There is disclosed a process for preparing purine derivatives of the formula I wherein, R1 represents hydrogen, CH3CO or a higher acyl,R3 represents hydrogen, CH3CO or a higher acyl, CF3CO, CCl3CO, PhCO or CH2 AR, such as benzyl or substituted benzyl, and benzoisothiazolyl-S,S-dioxide, and, Z represents OH, hydrogen or halo. Said compounds are either drugs or prodrugs for the treatment of herpes infections. There are also disclosed some novel compounds of formula I useful as prodrugs.
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- Efficient Synthesis of Acyclic Nucleosides by N-Alkylation of Pyrimidine and Purine-bases Using a New Coupling Agent of Cesium Iodide
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Acyclic nucleosides, ((1,3-bis(benzyloxy)-2-propoxy) methyl)-2-thio-pyrimidine, -uracil, -2-thiouracil, and -2-thioadenine, and (2-acetoxyethoxy methyl)-2-thioadenine, -2-thiopyrimidine, -uracil, and -2-thiouracil have been successfully synthesized in goo
- Kim, Yong Hae,Kim, Joong Young,Lee, Chun Ho
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p. 1045 - 1048
(2007/10/02)
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- 2-Amido-9-(2-acyloxyethoxymethyl)hypoxanthines
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Method of preparing 9-(2-hydroxyethoxymethyl)guanine which comprises preparing the compound STR1 wherein R and R1 are hydrogen, lower alkyl and phenyl and then hydrolyzing same. 9-(2-hydroxyethoxymethyl)guanine is useful as an antiviral.
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