Synthesis of phosphonate 3-phthalidyl esters as prodrugs for potential intracellular delivery of phosphonates

Bioorganic and Medicinal Chemistry Letters

Volumn 9, Issue 11, 1999, Pages 1505-1510

  Dang, Qun ^a   Brown, Brian S ^a   Van Poelje, Paul D ^a   Colby, Timothy J ^a   Erion, Mark D ^a  

^a Metabasis Therapeutics Inc   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

PHOSPHONIC ACID DERIVATIVE; PHTHALIDE DERIVATIVE; PRODRUG;

ANIMAL CELL; ARTICLE; CHEMICAL MODIFICATION; DRUG DELIVERY SYSTEM; DRUG HALF LIFE; DRUG STABILITY; DRUG SYNTHESIS; LIVER CELL; NONHUMAN; RAT;

ANIMALS; ESTERS; KINETICS; LIVER; NAPHTHALENES; PHOSPHONIC ACIDS; PRODRUGS; RATS;

ANIMALIA;

EID: 0033532714     PISSN: 0960894X     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0960-894X(99)00239-5     Document Type: Article

References (17)

1. For a review on phosphonate analogs of nucleotides as antiviral agents, see: Holy, A. In Advances in Antiviral Drug Design; De Clercq, E., Ed.; JAI: Greenwich, 1993; pp 179-231.
2. For reviews of phosphate and phosphonate prodrugs, see: Meier, C. Synlett 1998, 233. Krise, J. P.; Stella, V. J. Adv. Drug Delivery Rev. 1996, 19, 287.
3. For reviews of phosphate and phosphonate prodrugs, see: Meier, C. Synlett 1998, 233. Krise, J. P.; Stella, V. J. Adv. Drug Delivery Rev. 1996, 19, 287.
4. Srinivas, R. V.; Robbins, B. L.; Connelly, M. C.; Gong, Y.; Bischofberger, N.; Fridland, A. Antimicrob. Agents Chemother. 1993, 37, 2247.
5. Bentley, P. H.; Brooks, G.; Zomaya, I. I. Tetrahedron Lett. 1976, 3739. Clayton, J. P.; Cole, M.; Elson, S. W.; Ferres, H.; Hanson, J. C.; Mizen, L. W.; Sutherland, R. J. Med. Chem. 1976, 19, 1385.
6. Bentley, P. H.; Brooks, G.; Zomaya, I. I. Tetrahedron Lett. 1976, 3739. Clayton, J. P.; Cole, M.; Elson, S. W.; Ferres, H.; Hanson, J. C.; Mizen, L. W.; Sutherland, R. J. Med. Chem. 1976, 19, 1385.
7. NMPA was purchased from Lancaster and used as received.
8. Sugimoto, A.; Tanaka, H.; Eguchi, Y.; Ito, S.; Takashima, Y.; Ishikawa, M. J. Med. Chem. 1984, 27, 1300.
9. Cowell, A.; Stille, J. K. J. Am. Chem. Soc. 1980, 102, 4193.
10. 2O) C, H.
11. 10 Hepatocytes (75 mg wet weight/mL) were incubated in 1 mL Krebs-bicarbonate buffer containing 10 mM glucose and 1 mg/mL BSA. Incubations were carried out in an oxygen (95%)-carbon dioxide (5%) atmosphere in closed 50-mL Falcon tubes submerged in a rapidly shaking water bath (37 °C). Prodrugs were dissolved in DMSO to yield 10 mM stock solutions, and then diluted into the cell suspension to yield a final concentration of 100 M. After 1 h incubation, an aliquot of the suspension was removed and spun through a silicon/mineral oil layer into 10% perchloric acid. The cell extracts in the acid layers were neutralized, and the intracellular prodrug metabolite content analyzed by reverse phase HPLC using an ODS column. Gradient elution from 10 mM sodium phosphate (pH 5.5) to 75% acetonitrile was used and UV detection was set at 310 nm. Peaks on the chromatograms were identified by comparison to the retention times and spectra of prodrugs and NMPA standards.
12. Berry, M. N.; Friend, D. S. J. Cell Biol. 1969, 43, 506. Groen, A. K.; Sips, H. J.; Vervoorn, R. C; Tager, J. M. Eur J. Biochem. 1982, 122, 87.
13. Berry, M. N.; Friend, D. S. J. Cell Biol. 1969, 43, 506. Groen, A. K.; Sips, H. J.; Vervoorn, R. C; Tager, J. M. Eur J. Biochem. 1982, 122, 87.
14. 8 described above.
15. Rat plasma was prepared by centrifugation of fresh blood samples obtained from the posterior vena cava of anesthetized rats. Plasma samples were incubated at 37 °C in a shaking incubator, and prodrugs added from a 10 mM DMSO stock solution to yield a final concentration of 100 M. At appropriate time points after prodrug addition, aliquots of the incubation mixtures were removed and extracted by addition of methanol to 60%. Prodrug and parent drug content was quantified by HPLC as described above. Half-lives were determined graphically by plotting prodrug concentration versus time. NMPA was stable in the rat plasma.
16. 50 of 7500 mg/kg; formaldehyde is labelled as toxic, may cause cancer and heritable generic damage, while 2-carboxybenzaldehyde is labelled as irritant.
17. Although no solubility studies were conducted, these 3-phthalidyl esters appeared to have improved solubility compared to NMPA-diPOM. Because when a DMSO solution of NMPA-diPOM was added into the testing cellular medium, NMPA-diPOM oiled out and its activation could not be determined in this assay while these 3-phthalidyl esters did not present this problem. It is noteworthy that both the parent drug and the prodrug segments contribute to the actual solubility of final prodrugs. For example, NMPA is hydrophobic and therefore both NMPA-diPOM and its 3-phthalidyl esters appear to be very hydrophobic, however PMEA-diPOM has been developed into an oral drug.