title: Enhancements in gene expression by the choice of plasmid DNA formulations containing neutral polymeric excipients.
abstract: Formulations containing maltodextrin (2% w/v) were identified to facilitate intramuscular (im) delivery of plasmid DNA in mice using the reporter genes luciferase and chloramphenicol acetyltransferase (CAT) and the therapeutic gene of erythropoietin (EPO) as monitors of transfection efficiency. Even though considerable variability in gene expression was observed in animals, a 5-8-fold enhancement of reporter gene expression was observed with this excipient compared with saline formulations of DNA. In a therapeutically significant experiment, a single im injection of an EPO plasmid formulation containing 2% (w/v) maltodextrin resulted in a significant and prolonged elevation of the hematocrit levels of mice compared with control DNA in saline. Biophysical studies with Fourier transform infrared (FTIR) spectroscopy, isothermal titration, and differential scanning calorimetry (DSC) suggested a weak interaction between DNA and maltodextrin as well as a thermal stabilizing effect on the DNA. These in vivo and biophysical results with maltodextrin are comparable to those reported previously with other nonionic polymers, such as poly(vinyl pyrrolidone) and poloxamers, and indicate that maltodextrin is an additional nonionic excipient that displays the property of gene expression enhancement.
authors.affiliation: Department of Formulation Development, Chiron Corporation, 4560 Horton Street, Emeryville, CA 94608, USA. carol_huang@chiron.com
authors.forename: Chin-Yi
authors.initials: CY
authors.lastname: Huang
authors.forename: San San
authors.initials: SS
authors.lastname: Ma
authors.forename: Sandra
authors.initials: S
authors.lastname: Lee
authors.forename: Ramachandran
authors.initials: R
authors.lastname: Radhakrishnan
authors.forename: Chad S
authors.initials: CS
authors.lastname: Braun
authors.forename: Sirirat
authors.initials: S
authors.lastname: Choosakoonkriang
authors.forename: Chris M
authors.initials: CM
authors.lastname: Wiethoff
authors.forename: Brian A
authors.initials: BA
authors.lastname: Lobo
authors.forename: C Russell
authors.initials: CR
authors.lastname: Middaugh
mesh_terms: D000818:Animals; D002626:Chemistry, Pharmaceutical; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D004333:Drug Administration Routes; D004921:Erythropoietin / Q000235:genetics / Q000378:metabolism; D005079:Excipients; D005260:Female; D015870:Gene Expression; D018014:Gene Transfer Techniques; D007273:Injections, Intramuscular; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D015394:Molecular Structure; D010957:Plasmids / Q000008:administration & dosage*; D011108:Polymers; D013996:Time and Motion Studies; D014783:Viscosity
chemical_list: D005079:Excipients; D011108:Polymers; D004921:Erythropoietin; D008156:Luciferases; D015500:Chloramphenicol O-Acetyltransferase