title: Intradermal and follicular delivery of adapalene liposomes.
abstract: BACKGROUND
  Adapalene is a widely used topical anti-acne drug; however, it has many side effects. Liposomal drug delivery can play a major role by targeting delivery to pilosebaceous units, reducing side effects and offering better patient compliance.
  
  
  OBJECTIVE
  To prepare and evaluate adapalene-encapsulated liposomes for their physiochemical and skin permeation properties.
  
  
  METHODS
  A liposomal formulation of adapalene was prepared by the film hydration method and characterized for shape, size, polydispersity index (PDI), encapsulation efficiency and thermal behavior by techniques such as Zetasizer®, differential scanning calorimetry and transmission electron microscopy. Stability of the liposomes was evaluated for three months at different storage conditions. In vitro skin permeation studies and confocal laser microscopy were performed to evaluate adapalene permeation in pig ear skin and hair follicles.
  
  
  RESULTS
  The optimized process and formulation parameters resulted in homogeneous population of liposomes with a diameter of 86.66 ± 3.5 nm in diameter and encapsulation efficiency of 97.01 ± 1.84% w/w. In vitro permeation studies indicated liposomal formulation delivered more drug (6.72 ± 0.83 μg/cm(2)) in hair follicles than gel (3.33 ± 0.26 μg/cm(2)) and drug solution (1.62 ± 0.054 μg/cm(2)). Drug concentration delivered to the skin layers was also enhanced compared to other two formulations. Confocal microscopy images confirmed drug penetration in the hair follicles when delivered using the liposomal formulation.
  
  
  CONCLUSIONS
  Adapalene was efficiently encapsulated in liposomes and led to enhanced delivery in hair follicles, the desired target site for acne.
authors.affiliation: a Unither Pharmaceuticals , Rochester , NY , USA and.
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumar
authors.affiliation: b Department of Pharmaceutical Sciences , College of Pharmacy, Mercer University , Atlanta , GA , USA.
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Banga
mesh_terms: D000152:Acne Vulgaris / Q000188:drug therapy; D000068816:Adapalene / Q000008:administration & dosage* / Q000737:chemistry*; D000279:Administration, Cutaneous; D000818:Animals; D004337:Drug Carriers / Q000737:chemistry; D016503:Drug Delivery Systems / Q000379:methods; D004355:Drug Stability; D018859:Hair Follicle / Q000378:metabolism*; D008081:Liposomes / Q000008:administration & dosage* / Q000737:chemistry*; D010316:Particle Size; D010539:Permeability; D012867:Skin / Q000378:metabolism*; D012869:Skin Absorption; D013552:Swine
chemical_list: D004337:Drug Carriers; D008081:Liposomes; D000068816:Adapalene
keywords: Acne; adapalene; differential tape stripping; follicular targeting; topical delivery