Dual cross-linked pulsatile beads for chronotherapy of asthma: development and evaluation

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 5–7 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.