RESUMO
In the present investigation, pulsatile release beads were prepared by ionic gelation technique. Theophylline dual-cross-linked beads were prepared by dropping dispersed phase of theophylline, Delonix regia gum (DRG), and sodium alginate into the dispersion phase of different concentration of calcium chloride solution followed by aluminium chloride solution. The formulated beads were further coated by Eudragit L & S 100 in the ratio 1:2 w/w in order to achieve desired lag time. In vitro release study showed lag time of 57 h before release of theophylline from the formulated beads, which were found to be intact for 6 h. Thus, formulated dual cross-linked beads when administered at bed time may release theophylline when needed most for chronotherapeutics of early morning asthmatic attacks in chronic patients. In vivo radio imaging study carried out in New Zealand white strain rabbit confirms the findings of in vitro results.
Assuntos
Asma/tratamento farmacológico , Cronoterapia , Teofilina , Alginatos/química , Alginatos/farmacologia , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Broncodilatadores/farmacologia , Química Farmacêutica , Preparações de Ação Retardada/farmacologia , Portadores de Fármacos , Sistemas de Liberação de Medicamentos , Avaliação Pré-Clínica de Medicamentos , Excipientes , Fabaceae/química , Ácido Glucurônico/química , Ácido Glucurônico/farmacologia , Ácidos Hexurônicos/química , Ácidos Hexurônicos/farmacologia , Humanos , Manose/química , Manose/farmacocinética , Microesferas , Ácidos Polimetacrílicos/química , Ácidos Polimetacrílicos/farmacologia , Coelhos , Teofilina/farmacologiaRESUMO
The eye presents unique opportunities and challenges when it comes to the delivery of pharmaceuticals. In the present study, ocular inserts of levofloxacin were prepared using chitosan and gelatin by solvent casting technique with an aim to improve therapeutic efficacy in the treatment of conjunctivitis. Prepared ocular inserts were then evaluated for film thickness, weight variation, content uniformity, percentage moisture loss and absorption. In vitro drug release studies were carried out using flow through apparatus that simulated the eye conditions. Optimized formulations were subjected to in vivo and stability studies to assess the effectiveness of the formulations. Finally in vitro in vivo correlation was established. Plasticizer like PEG was found to influence their effect on drug release. Prepared ocular inserts exhibited zero order kinetics which was confirmed by strong and positive correlation. The in vitro and in vivo drug release studies revealed that the formulations provide a best alternative to prolong the drug release at the end of 24 h and remained stable with intact at ambient conditions.