Abstract
Montelukast is a leukotriene receptor antagonist (LTRA) used for the maintenance treatment of asthma, chronic asthma attacks and to relive symptoms of seasonal allergies. The main drawback of conventional Montelukast formulation is that it undergoes hepatic first pass metabolism. Thus, it shows plasma or biological half-life 2.5 to 5.5 hrs, thereby decreasing bioavailability upto 64%. The present work describes such delivery system, which will improve the biological half-life as well as bioavailability of Montelukast. This makes Montelukast a suitable candidate for incorporation in sustained-release dosage form and was used as a model drug. Thus the present investigation was aimed to develop timed release tablets of Montelukast sodium by compression coating using enteric coated polymers like Eudragit L-100 and S-100 to resist from acidic pH and prevent gastric irritation. The pre-compressional parameters such as angle of repose, bulk density, tapped density, Carrs index and Hausners ratio for the physical mixtures of the formulations were evaluated and the results were within the limits. The prepared core and compression-coated tablets were studied for their physical properties like weight variation, hardness, friability and drug content uniformity using reported procedure. All the post compressional parameters were within the limits. The FTIR studies were done for drug-excipient compatibility. The infra-red spectrum for pure drug and Montelukast sodium formulation. The following principal peaks were observed from the FT-IR spectral analysis. OI
O-H stretching seen in alcohols - 3212.619 cm-1
C=C stretching of the benzene ring - 1453.85 cm-1
C-H bend - 1589.987 cm-1
Calibration curves were constructed for Montelukast sodium in pH 1.2, 6.8 and 7.4 buffers with concentration ranging from 5 - 40 mu g/mL against absorbance at 332nm using UV spectrophotometer. The present analytical method obeyed Beers law within the concentration range and plots showed good linearity.
In vitro drug dissolution studies were carried out in pH 1.2 for 2 hrs, pH 6.8 for 4 hrs and pH 7.4 phosphate buffer for 8 hrs respectively and based on the in vitro drug release profiles, formulations F1, F2, F4, F5 and F7 has passed the criteria of Q NLT < 80% within 30 minutes of exposure in pH 7.4 phosphate buffer.