Application and validation of a coaxial liquid core waveguide fluorescence detector for the permeation analysis of desmopressin acetate

In recent years, the development of peptide drugs and alternative routes of administration, such as buccal and sublingual routes, has become increasingly important to the pharmaceutical industry. Performing experiments under physiologically relevant conditions is still a challenge that has not yet been fully mastered. The requirements associated with these alternative administration routes (e.g. permeation testing for buccal administration) push common analytical detection systems in pharmaceutical technology to their limits, especially with regard to large molecules and peptides. An HPLC-coupled coaxial liquid-core waveguide fluorescence detector has been developed and evaluated within this study to overcome these limits by achieving a more sensitive detection. Desmopressin acetate was selected as the peptide drug with the aim of investigating its permeation behavior during the clinically relevant application period of one hour. Based on the detector system, a complete validation according to the requirements of international guidelines was successfully performed. The results of the validation showed an increase in sensitivity resulting in a limit of detection of 4.7 ng/mL and a lower limit of quantification of 9.5 ng/mL. Moreover, it has been demonstrated that the permeation of desmopressin can be observed in clinically relevant dosages and time periods of up to one hour using this innovative detector system. [Display omitted] •Development of a HPLC-coupled coaxial liquid-core waveguide fluorescence detector.•Tenfold sensitivity enhancement compared to established fluorescence detection.•Successful validation according to ICH Q2 and EMA guidelines.•Permeation monitoring in clinically relevant dosages and time periods.