title: Formulation and evaluation of novel glycyrrhizic acid micelles for transdermal delivery of podophyllotoxin.
abstract: BACKGROUND
  As the first-line agent for genital warts, podophyllotoxin (POD) could induce extensively skin burning, itching, and erythema. Meanwhile, as a common anti-inflammatory agent, glycyrrhizic acid (GA), also has amphipathic and solubilizing properties, indicating that it might be a promising drug carrier.
  
  
  OBJECTIVE
  The objective of this study is to formulate and characterize the POD-loaded GA micelles preparation and to evaluate its drug release characteristics and anti-inflammatory properties.
  
  
  METHODS
  The novel micelles preparation was prepared by ultrasonic dispersion method and characterized using different scanning calorimetries, dynamic light scattering, and transmission electron microscopies. Subsequently, its encapsulation efficiency (EE), drug-loading content (LC), in vitro skin permeation, in vivo drug retention, and distribution of POD were detected. The anti-inflammatory effect of the preparation was reflected by HE staining and immunohistochemistry in the rat skin.
  
  
  RESULTS
  The POD-loaded GA micelles formed spherical shapes (approximately 10 nm) with an EE of 78.53 ± 2.17% and a LC of 7.293 ± 0.42%. Meaningfully, unlike the extensive distribution of the POD tincture throughout the skin tissue, POD released from the POD-loaded GA micelles mainly located in the epidermis and could maintain steady skin retention for 12 h. Moreover, the POD-loaded GA micelles induced less leukocyte infiltration and inflammatory factors (IL-6 and TNF-α) expression when compared with the POD tincture.
  
  
  CONCLUSIONS
  Our results suggested that the POD-loaded GA micelles could achieve a higher POD distribution in the epidermal layer as well as a lighter skin inflammation. This new POD delivery system might be a potential and promising candidate for genital warts and deserved further researches.
authors.affiliation: a Department of Pharmacy , Nanfang Hospital, Southern Medical University , Guangzhou , China and.
authors.forename: Yatian
authors.initials: Y
authors.lastname: Wang
authors.affiliation: a Department of Pharmacy , Nanfang Hospital, Southern Medical University , Guangzhou , China and.
authors.forename: Boxin
authors.initials: B
authors.lastname: Zhao
authors.affiliation: a Department of Pharmacy , Nanfang Hospital, Southern Medical University , Guangzhou , China and.
authors.forename: Shengqi
authors.initials: S
authors.lastname: Wang
authors.affiliation: a Department of Pharmacy , Nanfang Hospital, Southern Medical University , Guangzhou , China and.
authors.forename: Qianying
authors.initials: Q
authors.lastname: Liang
authors.affiliation: a Department of Pharmacy , Nanfang Hospital, Southern Medical University , Guangzhou , China and.
authors.forename: Yun
authors.initials: Y
authors.lastname: Cai
authors.affiliation: b Department of Pharmacy , Zhuhai Maternal and Child Health Hospital , Zhuhai , China.
authors.forename: Fuheng
authors.initials: F
authors.lastname: Yang
authors.affiliation: a Department of Pharmacy , Nanfang Hospital, Southern Medical University , Guangzhou , China and.
authors.forename: Guofeng
authors.initials: G
authors.lastname: Li
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D002152:Calorimetry, Differential Scanning; D002626:Chemistry, Pharmaceutical; D016503:Drug Delivery Systems; D019695:Glycyrrhizic Acid / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D008823:Micelles; D011034:Podophyllotoxin / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D014409:Tumor Necrosis Factor-alpha / Q000737:chemistry* / Q000378:metabolism
chemical_list: D008823:Micelles; D014409:Tumor Necrosis Factor-alpha; D019695:Glycyrrhizic Acid; D011034:Podophyllotoxin
keywords: Anti-inflammation; glycyrrhizic acid; micelles; podophyllotoxin; skin permeation