title: Co-delivery of an antisense oligonucleotide and 5-fluorouracil using sustained release poly (lactide-co-glycolide) microsphere formulations for potential combination therapy in cancer.
abstract: Antisense oligonucleotides (AODNs) can selectively inhibit oncogene expression by Watson-Crick hybridisation to target mRNA and are being increasingly considered for use in combination with conventional drugs for potential anticancer therapy. Combination therapy of AODNs and cytotoxic agents using biodegradable polymeric delivery systems potentially offers several advantages including site-specific or organ-directed targeting, protection from digesting enzymes, and improved pharmacokinetics/pharmacodynamics resulting from sustained delivery of the entrapped drugs. Using a model AODN targeting the epidermal growth factor receptor (that is over-expressed in several cancers including breast and brain cancer) and the commonly used cytotoxic agent, 5-fluorouracil (5-FU), we have examined the use of poly (lactide-co-glycolide) (P(LA-GA)) microsphere formulations for co-delivery of these agents. Both agents were either co-entrapped in a single microsphere formulation or individually entrapped in two separate microsphere formulations and release profiles determined in vitro. Using a double emulsion method for preparing the P(LA-GA) microspheres suitable entrapment and sustained release over 35 days was observed in both types of formulation. Release of AODN and 5-FU from all formulations appeared to be biphasic. However, the release rates of the two agents were significantly slower when co-entrapped as a single microsphere formulation compared to those obtained with the separate formulations. Electrophoretic mobility shift assays suggested that this might be, in part, due to an interaction of 5-FU with the oligodeoxynucleotide (ODN). Further, our data suggest that by mixing individual formulations of 5-FU and ODNs at different mass ratios allowed greater flexibility in achieving the desired release profile as well as avoiding potential drug-drug interactions. Thus, co-administration of individual P(LA-GA) microsphere formulations of AODNs and 5-FU, at appropriate mass ratios, appears worthy of further investigation for the potential co-delivery of these anti-cancer agents in vivo.
authors.affiliation: Aston Centre for Gene-based Therapeutics (ACGT) Pharmaceutical Sciences Research Institute, Aston University, Birmingham B4 7ET, UK.
authors.forename: Majad
authors.initials: M
authors.lastname: Hussain
authors.forename: Gary
authors.initials: G
authors.lastname: Beale
authors.forename: Marcus
authors.initials: M
authors.lastname: Hughes
authors.forename: Saghir
authors.initials: S
authors.lastname: Akhtar
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage* / Q000627:therapeutic use; D004338:Drug Combinations; D004347:Drug Interactions; D004586:Electrophoresis; D005472:Fluorouracil / Q000008:administration & dosage / Q000627:therapeutic use; D019344:Lactic Acid; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage / Q000627:therapeutic use; D010316:Particle Size; D010761:Phosphorus Radioisotopes; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers
chemical_list: D000964:Antimetabolites, Antineoplastic; D000970:Antineoplastic Agents; D004338:Drug Combinations; D016376:Oligonucleotides, Antisense; D010761:Phosphorus Radioisotopes; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D005472:Fluorouracil