title: Preparation and evaluation of a new nano pharmaceutical excipients and drug delivery system based in polyvinylpyrrolidone and silicate.
abstract: OBJECTIVE
  This work describes the preparation of new nanocomposites based on lamellar silicates (AAM-alkyl ammonium montmorillonite) obtained by the intercalation of PVP K30 and glyceril monostearate.
  
  
  METHODS
  By XRD, TGA and DSC analysis the AAM was characterized and its compactation characteristics, functionality and toxicity were also tested. The AAM/PVP K-30 and AAM/GME nanocomposite obtained were evaluated to identify the interlamellar spacing values by XRD diffratograms. Tablets were prepared using methyldopa and theophylline as model drugs and the dissolution tests were carried out in simulated gastric fluid and simulated enteric fluid.
  
  
  RESULTS
  AAM showed a good compactability and compressibility characteristics for tablets preparation. The intercalation yields (approximately 25%) of the nanocomposites were efficient. The AAM/PVP K-30 nanocomposites were successfully tested as dissolution enhancers and sustained release matrixes.
  
  
  CONCLUSIONS
  The results also suggested the promising use of AAM (viscogel B8) and the new nanocomposite prepared by clay/PVP K-30 intercalation as a new matrix for sustained release and the feasibility of using these new nanocomposites as dissolution enhancer.
authors.affiliation: Departamento de Medicamentos, Faculdade de Farmácia, UFRJ, Rio de Janeiro, RJ, Brazil.
authors.forename: Camila Braga
authors.initials: CB
authors.lastname: Dornelas
authors.forename: Alex Moura
authors.initials: AM
authors.lastname: da Silva
authors.forename: Cide Brizio
authors.initials: CB
authors.lastname: Dantas
authors.forename: Carlos Rangel
authors.initials: CR
authors.lastname: Rodrigues
authors.forename: Sandra Solange
authors.initials: SS
authors.lastname: Coutinho
authors.forename: Plínio Cunha
authors.initials: PC
authors.lastname: Sathler
authors.forename: Helena Carla
authors.initials: HC
authors.lastname: Castro
authors.forename: Luiza Rosaria Sousa
authors.initials: LR
authors.lastname: Dias
authors.forename: Valéria Pereira
authors.initials: VP
authors.lastname: de Sousa
authors.forename: Lúcio Mendes
authors.initials: LM
authors.lastname: Cabral
mesh_terms: D000818:Animals; D001546:Bentonite / Q000737:chemistry / Q000633:toxicity; D002152:Calorimetry, Differential Scanning; D016503:Drug Delivery Systems; D005079:Excipients / Q000737:chemistry* / Q000633:toxicity; D008750:Methyldopa / Q000008:administration & dosage / Q000737:chemistry; D051379:Mice; D053761:Nanocomposites; D011205:Povidone / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D012995:Solubility; D013607:Tablets; D013806:Theophylline / Q000008:administration & dosage / Q000737:chemistry; D013818:Thermogravimetry; D018675:Toxicity Tests; D014961:X-Ray Diffraction
chemical_list: D005079:Excipients; D017640:Silicates; D013607:Tablets; D001546:Bentonite; D008750:Methyldopa; D013806:Theophylline; D011205:Povidone