Effect assessment of “film coating and packaging” on the photo-stability of highly photo-labile antihypertensive products

INTRODUCTION: Lacidipine (LCDP) is chemically a “1, 4-dihydropyridine derivative” Ca+(2) channel blocker used as an antihypertensive. Type and extent of packaging have a strong influence on the photo-stability of the 1,4-dihydropyridine derivatives. In standard, light protection of drug substance/drug product can be obtained either by use of an opaque additive in the formulation that competitively absorbs or reflects light reaching the sample and/or by blocking the access of light to the drug through external protection by packaging. MATERIALS AND METHODS: External protection by covering tablets with an opaque film coating involving a light-reflecting inorganic pigment such as titanium dioxide and/or by using an opaque impermeable packaging material was an appropriate suitable option for establishing photo-stability. Thus, the main objective of the present study was to optimize the % level of film coating in LCDP core tablets, and selection of a final packaging material and its respective extent, that is, primary, secondary and/or tertiary packaging, for LCDP tablets. RESULTS AND CONCLUSION: The main objective (% level of film coating) was optimized by directly exposing core tablets, 1% w/w, 2% w/w and 3% w/w film-coated tablets, to a light source as per Option-2 of ICH Q1B and its comparative analysis at the end of light exposure testing. The other objective (extent of drug product packaging) was established successfully by assessing whether or not an acceptable change has occurred at the end of the light exposure testing of the LCDP film-coated tablets in a direct exposure study or a primary immediate pack and/or secondary marketing pack.