Light transmission properties of pharmaceutical liquid bottles and evaluation of their photoprotective efficacy

Abstract

The light sensitive pharmaceutical dosage forms are well protected from light by packing in light protective bottles especially the colored glass and plastic bottles. In the present study the transmission characteristics of transparent glass bottle, amber glass bottle, polyvinyl chloride amber plastic bottle (PVC) and low density polyethylene semi-opaque plastic bottles (LDPE) (empty and drug filled) have been evaluated and the data compared for compliance with Pharmacopoeial limits of percentage transmission. The variations in thickness affect the amount of light transmitted through the bottles. For an average thickness, the transmission of bottles was not uniform indicated the effect of manufacturing variables on the transmission of light. The drug filled bottles showed an increase in light transmission probably as a result of interaction between drug and bottle components. The leaching of any coloring agents from glass bottles or the pigments from plastic bottles into the solution during storage appeared to increase the transmission of light which could be detrimental to photosensitive drugs in a formulation. The light protective efficacy of bottles was in the order: Semi-opaque plastic (LDPE) > amber plastic (PVC) > amber glass. The photoprotection of aqueous solution of riboflavin as a model compound in these bottles has been studied and its shelf-lives and stability ratio were determined.