title: Development of the loratadine gel for enhanced transdermal delivery.
abstract: BACKGROUND
  The oral administration of loratadine, an antihistamine, can have a variety of adverse side effects, such as headache, fatigue, and nausea, because of the transient high blood concentration. To avoid these effects, loratadine can be administered using a transdermal drug delivery system.
  
  
  METHODS
  This study examined the effects of the drug concentration on drug release from prepared hydroxypropyl methylcellulose gels using a synthetic cellulose membrane at 37 degrees C. The drug concentrations tested were 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% (w/w). The effect of temperature on drug release from the 0.3% loratadine gels was evaluated at 27 degrees C, 32 degrees C, 37 degrees C, and 42 degrees C. Various types of penetration enhancers, such as glycols, glycerides, propylene glycol derivatives, nonionic surfactants, and fatty acids, were incorporated in the gel formulation to increase the level of drug permeation.
  
  
  RESULTS
  The rate of drug release increased with increasing drug concentration or temperature. The activation energy for the release of the drug was 5.714 kcal/mol for 0.3% loratadine gel. Among all the enhancers used in this study, polyoxyethylene 2-stearyl ether showed the best enhancing effect. The enhancement factor of the loratadine gel containing the polyoxyethylene 2-stearyl ether was 2.03 compared with that of the loratadine system containing no enhancer.
  
  
  CONCLUSIONS
  These results suggest that the topical gel formulation of loratadine containing a penetration enhancer could be developed to enhance the penetration of loratadine.
authors.affiliation: College of Pharmacy, Chonnam National University, Buggu, Gwangju, Republic of Korea.
authors.forename: Jae-Haeng
authors.initials: JH
authors.lastname: Song
authors.forename: Sang-Chul
authors.initials: SC
authors.lastname: Shin
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D004337:Drug Carriers / Q000737:chemistry*; D005079:Excipients / Q000737:chemistry*; D005782:Gels; D039563:Histamine H1 Antagonists, Non-Sedating / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D065347:Hypromellose Derivatives; D017336:Loratadine / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D008297:Male; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012869:Skin Absorption; D013696:Temperature
chemical_list: D004337:Drug Carriers; D005079:Excipients; D005782:Gels; D039563:Histamine H1 Antagonists, Non-Sedating; D065347:Hypromellose Derivatives; D011092:Polyethylene Glycols; D017336:Loratadine; D008747:Methylcellulose; C043444:octadecyl polyoxyethylene ether