CriticalSorb™: A novel efficient nasal delivery system for human growth hormone based on Solutol HS15

The absorption enhancing efficiency of CriticalSorb™ for human growth hormone (MW 22 kDa) was investigated in the conscious rat model. The principle absorption enhancing component of CriticalSorb™, Solutol® HS15, comprises polyglycol mono- and di-esters of 12-hydroxystearic acid combined with free polyethylene glycol. When administering hGH nasally in rats with increasing concentrations of Solutol® HS15, it was found that for a 10%w/v solution formulation a bioavailability of 49% was obtained in the first 2 h after administration. Furthermore it was shown that the most effective ratio of Solutol® HS15 to hGH was 4:1 on a mg to mg basis. Histopathology studies in rats after 5 days repeated nasal administration showed that Solutol® HS15 had no toxic effect on the nasal mucosa. These results have been confirmed in a 6 month repeat nasal toxicity study in rats. It can be concluded that the principle absorption enhancing component of CriticalSorb™ – Solutol® HS15 – is a potent and non- toxic nasal absorption enhancer that warrants further development.