RESUMO
Based on an elementary osmotic pump, controlled release systems of diclofenac sodium (DS) were designed to deliver the drug in a zero-order release pattern. Osmotic pump tablets containing 100 mg DS were prepared and coated with either semipermeable (SPM) or microporous (PM) membranes. The tablet coats were composed of hydrophobic triacetin (TA) or hydrophilic polyethylene glycol 400 (PEG 400) incorporated in cellulose acetate (CA) solution, for SPM and PM, respectively. Variable tablet core compositions such as swelling polymers (PEO and HPMC) and osmotic agents (lactose, NaCl, and KCl) were studied. An optimized, sensitive and well controlled in vitro release design, based on the flow-through cell (FTC), was utilized to discriminate between preparations. The results revealed that the presence of PEG 400 in the coating membrane accelerated the drug release rate, while TA suppressed the release rate of DS. In the case of SPM, the amount of DS released was inversely proportional to the membrane thickness, where 5% (w/w) weight gain gave a higher DS release rate than 10% (w/w). Results of different tablet core compositions revealed that the release rate of DS decreased as PEO molecular weight increased. HPMC K15M showed the lowest DS release rate. The presence of lactose, KCl, or NaCl pronouncedly affected DS release rate depending on polymer type in the core. Scanning electron microscopy (SEM) confirmed formation of pores in the membrane that accounts for faster DS release rate. These results revealed that DS could be formulated as an osmotic pump system with a prolonged, zero-order release pattern.
Assuntos
Anti-Inflamatórios não Esteroides/química , Diclofenaco/química , Membranas Artificiais , Anti-Inflamatórios não Esteroides/administração & dosagem , Celulose/análogos & derivados , Celulose/química , Química Farmacêutica , Preparações de Ação Retardada , Diclofenaco/administração & dosagem , Excipientes/química , Interações Hidrofóbicas e Hidrofílicas , Derivados da Hipromelose , Cinética , Lactose/química , Metilcelulose/análogos & derivados , Metilcelulose/química , Microscopia Eletrônica de Varredura , Osmose , Plastificantes/química , Polietilenoglicóis/química , Porosidade , Cloreto de Potássio/química , Cloreto de Sódio/química , Solubilidade , Propriedades de Superfície , Comprimidos , Tecnologia Farmacêutica/métodos , Triacetina/químicaRESUMO
The effect of solid dispersion techniques on the antimicrobial activity of chloramphenicol has been studied and it was proven that the antimicrobial activity of chloramphenicol is not affected when the drug is present as a coprecipitate with carbowaxes (4.000, 6.000, 12.000), and PVP 11.000 and 40.000) also in fusion systems with these polymers. In contrast, the antimicrobial activity of the drug is enhanced when it is present in the from of a solid dispersion system.
Assuntos
Cloranfenicol/farmacologia , Escherichia coli/efeitos dos fármacos , Formas de Dosagem , Concentração de Íons de HidrogênioRESUMO
A study was conducted on the effect of certain additives on the dissolution rate of chloramphenicol. The effect of adsorbents, natural and synthetic surface active agents, diluents and lubricants was studied. Many of these additives increased the dissolution rate of chloramphenicol from capsules.
Assuntos
Cloranfenicol/análise , Álcoois , Cápsulas , Carboidratos , Química Farmacêutica , Temperatura Baixa , Excipientes , Solubilidade , Estearatos , Tensoativos , Fatores de TempoRESUMO
Suppositories of chlorphenamine maleate were formulated. The influence of particle size and percentage concentration of chlorphenamine maleate on the physical standards of its suppositories as well as the release of the drug from oily base (cacao butter), water-soluble base (carbowax) and emulsifying base (Witepsol) has been investigated.
