Surface tension examination of various liquid oral, nasal, and ophthalmic dosage forms
Surface tension at the surface to air interface is a physico chemical property of liquid pharmaceutical formulations that are often overlooked. To determine if a trend between surface tension and route of administration exists, a suite of oral, nasal, and ophthalmic drug formulations were analyzed. The surface tension at the surface to air interface of the oral formulations studied were in or above the range of the surface tension of gastric, duodenum, and jejunum fluids. The range of surface tensions for oral formulations were 36.6 64.7 dynes/cm. Nasal formulations had surface tensions below that of the normal mucosal lining fluid with a range of 30.3 44.9 dynes/cm. Ophthalmic OTC formulations had the largest range of surface tensions at the surface to air interface of 34.3 70.9 dynes/cm; however, all formulations indicated for treatment of dry eye had surface tensions higher than that of normal tears, while those for treatment of red eye had surface tensions below. Therefore, surface tension at the surface to air interface of liquid formulations is dependent on the route of administration, environment at site of introduction, and for ophthalmics, what the formulation is indicated for.
Chemistry Central Journal