title: In Vitro Evaluation of pH Responsive Doxazosin Loaded Mesoporous Silica Nanoparticles: A Smart Approach in Drug Delivery.
abstract: OBJECTIVE
  To develop a pH responsive drug delivery system (DDS) for controlled release of therapeutic cargo, Doxazosin Mesylate (DZM) which was loaded into carrier material mesoporous silica nanoparticle (MSN) and subsequently coated with Eudragit S-100(ES-100) to release the drug at pH 7.4.
  
  
  METHODS
  We have synthesized cylindrical MSN under acidic condition using non-ionic surfactant (Pluronic(®) P 123) and Tetraethoxysilane (TEOS). After post synthesis treatment (PST) surfactant was removed by calcination. To obtain pH sensitive release calcined MSN was coated with ES-100 (MSN-DZMES100). The Brauner-Emmett-Teller (BET) surface area, adsorption isotherm, t-plot, pore volume of MSN were done in surface area analyzer to characterize different MSN samples (as synthesized, calcined, and coated).
  
  
  CONCLUSIONS
  Highest surafce area (427.114 m(2)/g) was observed in case of calcined sample when compared to as synthesized (3.1198m(2)/g) and coated MSN (8.8480m(2)/g). Adsorption pore width of final coated sample was 12.58 nm whereas as synthesized and calcined samples possessed pore width 36.82 nm and 7.32 nm respectively. All uncoated and coated MSN samples were further characterized with FESEM, TEM, FTIR. No significant interaction between drug and MSN was found from FTIR studies. The drug loading into coated mesoporous support was found to be 43.7%. In vitro studies were done at different pH using Franz-diffusion cell. Results showed significant release at pH 7.4 from MSNDZM- ES100. Cumulative drug release over a period of 10 hr was 81% at this systemic pH.
  
  
  CONCLUSIONS
  ES-100 coated mesoporous silica nanoparticle is a smart carrier for pH responsive release of guest molecule.
authors.forename: Arijit
authors.initials: A
authors.lastname: Guha
authors.forename: Nikhil
authors.initials: N
authors.lastname: Biswas
authors.forename: Kaustav
authors.initials: K
authors.lastname: Bhattacharjee
authors.forename: Piu
authors.initials: P
authors.lastname: Das
authors.affiliation: Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India. ketousetuoju@yahoo.in.
authors.forename: Ketousetuo
authors.initials: K
authors.lastname: Kuotsu
mesh_terms: D017292:Doxazosin / Q000008:administration & dosage*; D004337:Drug Carriers; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D053758:Nanoparticles / Q000737:chemistry*; D033362:Powder Diffraction; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry
chemical_list: D004337:Drug Carriers; D012822:Silicon Dioxide; D017292:Doxazosin