Formulation and evaluation of pulsatile drug delivery system of salbutamol sulfate for the chronotherapy of asthma

Abstract

Objective: The main objective of the present study was to design and evaluate a time-controlled single unit oral pulsatile drug delivery system containing salbutamol sulfate for the prevention of nocturnal asthma attacks. Methods: Drug containing core tablets (C1-C10) with different composition of superdisintegrants such as sodium starch glycolate, croscarmellose sodium, and crospovidone were prepared by direct compression technique. The fast disintegrating core tablet formulation was selected, and press-coated tablets (P1-P11) were prepared with different compositions of hydrophobic and hydrophilic polymers: Ethylcellulose-20 (EC-20), hydroxypropyl methylcellulose K4M, and low substituted hydroxypropyl cellulose (L-HPC LH11). The coating polymers were selected and quantified based on in vitro lag time and drug release profile in simulated gastric and intestinal fluids. Results: Formulation C10 with 7.5% crospovidone showed least disintegrating time, i.e., 0.31 min and was selected as the best immediate release core tablet. The press-coated tablet formulation P11 having 360 mg barrier layer of EC-20 and L-HPC LH11 in ratio 14:1 over the core tablet C10 showed rapid and complete drug release nearly after 6 h lag time. Accelerated stability studies of the optimized formulation P11 indicated no significant difference in release profile after a period of 6 months. Conclusion: The in vitro dissolution study showed that lag time before drug release was highly affected by the coating level and nature of coating polymer used. Time-controlled pulsatile release tablets can be prepared using press-coating techniques.