Morphologic examination of rabbit nasal mucosa after the nasal administration of insulin peanut oil suspension and a powder dosage form with soybean-derived sterylglucoside

Concept of sequential analysis of free and conjugated phytosterols in different plant matrices

A unique concept and method for the determination of the total plant sterol content as sum of free sterols (FS), steryl esters (SE), steryl glycosides (SG) and acylated steryl glycosides (ASG) in different plant materials (pumpkin seeds, lecithins) and phytopharmaceuticals derived thereof, was developed. For this purpose, a multidimensional sample clean-up protocol based on efficient solid-phase extraction materials was elaborated and the SG were isolated employing a novel phenyl boronic acid modified silica gel material. Along this line also a set of steryl glucosides was synthesised and employed as internal standard and for calibration in the course of quantitative analysis. Final quantification of SG was carried out with reversed-phase HPLC in combination with evaporative light scattering detection (ELSD); the ASG were determined after conversion to SG by mild alkaline hydrolysis. In order to determine the total plant sterol profile the sum of FS and SE was additionally analysed from the unsaponifiable lipid fraction by GC-FID. The yields obtained from recovery tests for the determination of SG using soya lecithin as matrix to which 2, 20 and 40 mg/g of cholesterol-beta-D-glucoside was added were 99.10, 98.07 and 90.00%, and the RSDs were 4.11, 2.62 and 4.50%, respectively. Application related to the qualitative and quantitative analysis of total phytosterol profiles in different plant matrices and extracts demonstrate the validity of the method.

Review on the systemic delivery of insulin via the ocular route

Systemic drug absorption from the ocular route is well known. Although there is some absorption from the conjunctival sac, the nasal meatus is the site where the majority of systemic absorption of instilled drug takes place. This article reviews the principles of systemic absorption of insulin applied topically to the eye. The physiological and pharmaceutical considerations for formulation development and the strategy of improving the systemic absorption and bioavailability of insulin are also discussed.