title: A pharmaceutical study on chlorzoxazone orodispersible tablets: formulation, in-vitro and in-vivo evaluation.
abstract: BACKGROUND
  Muscle spasm needs prompt relief of symptoms. Chlorzoxazone is a centrally muscle relaxant.
  
  
  OBJECTIVE
  The aim of this study was to prepare chlorzoxazone orodispersible tablets (ODTs) allowing the drug to directly enter the systemic circulation and bypassing the first-pass metabolism for both enhancing its bioavailability and exerting a rapid relief of muscular spasm.
  
  
  METHODS
  ODTs were prepared by direct compression method using Pharmaburst®500, Starlac®, Pearlitol flash®, Prosolv® odt and F-melt® as co-processed excipients. Three ratios of the drug to the other excipients were used (0.5:1, 1:1 and 2:1).
  
  
  CONCLUSIONS
  All ODTs were within the pharmacopeial limits for weight and content. ODTs containing Pharmaburst®500 showed the shortest wetting time (∼45.33 s), disintegration time (DT) (∼43.33 s) and dissolution (Q15min100.63%). By increasing the ratio of CLZ: Pharmaburst®500 from 0.5:1 to 1:1 and 2:1, the DT increased from 26.43 to 28.0 and 43.33 s, respectively. By using Prosolv® odt, ODTs failed to disintegrate in an acceptable time >180 s. DT of ODTs using different co-processed excipients can be arranged as follows: Pharmaburst® 500 < F-melt® <Pearlitol flash® <Starlac® <Prosolv® odt. Pharmacokinetic study of the optimum formula F1 (50 mg CLZ) in rabbits using HPLC-UV detector revealed a shorter Tmax(0.333 h) compared with Myofen® capsules (250 mg CLZ) (1.083 h) which is considered a promising treatment, especially for the rapid relief of muscle spasm.
  
  
  CONCLUSIONS
  It could be concluded that orodispersible tablets are a promising carrier for CLZ designed for management of muscle spasm due to the enhanced dissolution and rapid absorption of the drug through the oral mucosa.
authors.affiliation: a Department of Pharmaceutics and Industrial Pharmacy , Faculty of Pharmacy, Cairo University , Cairo , Egypt.
authors.forename: Helal Abdo
authors.initials: HA
authors.lastname: Moqbel
authors.affiliation: a Department of Pharmaceutics and Industrial Pharmacy , Faculty of Pharmacy, Cairo University , Cairo , Egypt.
authors.forename: Aliaa Nabil
authors.initials: AN
authors.lastname: ElMeshad
authors.affiliation: a Department of Pharmaceutics and Industrial Pharmacy , Faculty of Pharmacy, Cairo University , Cairo , Egypt.
authors.forename: Mohamed Ahmed
authors.initials: MA
authors.lastname: El-Nabarawi
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D002626:Chemistry, Pharmaceutical / Q000379:methods; D002753:Chlorzoxazone / Q000493:pharmacokinetics*; D004339:Drug Compounding / Q000379:methods; D005079:Excipients / Q000737:chemistry; D008297:Male; D011817:Rabbits; D012995:Solubility; D013035:Spasm / Q000188:drug therapy / Q000378:metabolism*; D013607:Tablets / Q000493:pharmacokinetics*
chemical_list: D005079:Excipients; D013607:Tablets; D002753:Chlorzoxazone
keywords: Bioavailability; co-processed excipients; disintegration time; fast dissolving tablets; muscle relaxant