title: Aqueous nanomicellar formulation for topical delivery of biotinylated lipid prodrug of acyclovir: formulation development and ocular biocompatibility.
abstract: OBJECTIVE
  The objective of this study was to develop a clear, aqueous nanomicellar formulation and evaluate its in vitro ocular biocompatibility as a novel carrier for topical ocular delivery of biotinylated lipid prodrug for the treatment of herpetic keratitis.
  
  
  METHODS
  Micellar formulation of Biotin-12Hydroxystearic acid-acyclovir (B-12HS-ACV) was prepared by solvent evaporation/film hydration method with two nonionic surfactants, vitamin E TPGS and octoxynol-40. The optimized formulation was characterized for various parameters including micelle size, polydispersity index (PDI), and zeta-potential and in vitro prodrug release. Human corneal epithelial cells (HCECs) were employed for studying the cytotoxicity of the formulation. Further, mRNA expression levels of various cytokines were also studied with quantitative real-time PCR (qPCR).
  
  
  RESULTS
  Average size was 10.46±0.05 nm with a PDI of 0.086 for blank nanomicelles, and 10.78±0.09 nm with a PDI of 0.075 for prodrug-loaded nanomicelles. Both unloaded and prodrug-loaded nanomicelles had low negative zeta potential. Prodrug encapsulation efficiency of mixed nanomicelles was calculated to be ∼90%. Transmission electron microscopy analysis revealed that nanomicelles were spherical, homogenous, and devoid of aggregates. B-12HS-ACV release from nanomicelles was slow with no significant burst effect. Results show a sustained release of the prodrug from nanomicelles over a period of 4 days. Neither the blank formulation nor the prodrug-loaded micellar formulation demonstrated any cytotoxic effects. Further, incubation of HCECs with blank and prodrug-loaded nanomicellar groups did not significantly alter the expression levels of IL-1β, IL-6, IL-8, IL-17, TNF-α, and IFN-γ.
  
  
  CONCLUSIONS
  In summary, a topical clear, aqueous nanomicellar formulation comprised of vitamin E TPGS and octoxynol-40 loaded with 0.1% B-12HS-ACV was successfully developed. B-12HS-ACV-loaded nanomicelles are small in size, spherical, and homogenous, without any aggregates. The micellar formulations were perfectly transparent similar to pure water. Ocular biocompatibility studies indicated that mixed nanomicelles were nontoxic and noninflammatory to corneal epithelial cells. Therefore, nanomicellar technology represents a promising strategy for the delivery of biotinylated lipid prodrugs of ACV.
authors.affiliation: Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City , Kansas City, Missouri.
authors.forename: Aswani Dutt
authors.initials: AD
authors.lastname: Vadlapudi
authors.forename: Kishore
authors.initials: K
authors.lastname: Cholkar
authors.forename: Ramya Krishna
authors.initials: RK
authors.lastname: Vadlapatla
authors.forename: Ashim K
authors.initials: AK
authors.lastname: Mitra
mesh_terms: D000212:Acyclovir / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000633:toxicity; D060433:Administration, Ophthalmic; D000998:Antiviral Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000633:toxicity; D019921:Biotinylation; D016207:Cytokines / Q000235:genetics; D016503:Drug Delivery Systems; D019573:Epithelium, Corneal / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D016849:Keratitis, Herpetic / Q000188:drug therapy; D008055:Lipids / Q000737:chemistry; D008823:Micelles; D053758:Nanoparticles; D017830:Octoxynol / Q000737:chemistry; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D011355:Prodrugs; D060888:Real-Time Polymerase Chain Reaction; D013501:Surface-Active Agents / Q000737:chemistry; D014810:Vitamin E / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D000998:Antiviral Agents; D016207:Cytokines; D008055:Lipids; D008823:Micelles; D011355:Prodrugs; D013501:Surface-Active Agents; D014810:Vitamin E; D011092:Polyethylene Glycols; D017830:Octoxynol; C014225:tocophersolan; D000212:Acyclovir