ABSTRACT
The objective of this research work was to prepare a chrono- modulated drug delivery system to meet chronopharmacological needs of asthma. In this study doxofylline was selected as a model drug. To meet this objective an initial lag phase of release for 3-5 hrs and later a rapid (surge) release phase was considered. To achieve surge release a rapidly releasing core tablet of doxofylline was developed by admixing doxofylline with effervescent granules and super disintegrants. The lag phase in release (2hr) was achieved by coating EV core tablets with release retarding polymers Eudragit RS-100 6% containing HPMC (Hydroxy Propyl Methyl Cellulose) 5%, further over coated with enteric polymer CAP (Cellulose Acetate Phthalate) 12%. The formulated chronomodulated tablets of doxofylline were able to release more than 90% drug within 4 hrs after the lag phase of 2 hrs.