eprintid: 10103722 rev_number: 19 eprint_status: archive userid: 608 dir: disk0/10/10/37/22 datestamp: 2020-07-06 14:01:11 lastmod: 2021-10-09 22:41:23 status_changed: 2020-07-06 14:01:11 type: article metadata_visibility: show creators_name: Lane, M creators_name: Goh, C creators_name: Craig, D creators_name: Boyd, BJ title: Profiling of drug crystallization in the skin ispublished: pub divisions: UCL divisions: B02 divisions: C08 divisions: D10 divisions: G08 note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions. abstract: Background: Drug crystallization following application of transdermal and topical formulations may potentially compromise the delivery of drugs to the skin. This phenomenon was found to be limited to the superficial layers of the stratum corneum (~7 µm) in our recent reports and tape stripping of the skin samples was necessary. It remains a significant challenge to profile drug crystallization in situ without damaging the skin samples. Methods: This work reports the application of an X-ray microbeam via synchrotron SAXS/WAXS analysis to monitor drug crystallization in the skin, especially in the deeper skin layers. Confocal Raman spectroscopy (CRS) was employed to examine drug distribution in the skin to complement the detection of drug crystallization using SAXS/WAXS analysis. Results: Following application of saturated drug solutions (ibuprofen, diclofenac acid, and salts), CRS depth profiles confirmed that the drugs generally were delivered to a depth of ~15 – 20 µm in the skin. This was compared with the WAXS profiles that measured drug crystal diffraction at a depth of up to ~25 µm of the skin. Conclusion: This study demonstrates the potential of synchrotron SAXS/WAXS analysis for profiling of drug crystallization in situ in the deeper skin layers without pre-treatment for the skin samples. date: 2020 date_type: published publisher: Informa Healthcare official_url: https://doi.org/10.1080/17425247.2020.1792440 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1795034 doi: 10.1080/17425247.2020.1792440 lyricists_name: Craig, Duncan lyricists_name: Lane, Majella lyricists_id: DQMCR05 lyricists_id: MLANE69 actors_name: Lane, Majella actors_id: MLANE69 actors_role: owner full_text_status: public publication: Expert Opinion on Drug Delivery volume: 17 number: 9 pagerange: 1321-1334 issn: 1742-5247 citation: Lane, M; Goh, C; Craig, D; Boyd, BJ; (2020) Profiling of drug crystallization in the skin. Expert Opinion on Drug Delivery , 17 (9) pp. 1321-1334. 10.1080/17425247.2020.1792440 <https://doi.org/10.1080/17425247.2020.1792440>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10103722/1/EODD-2020-ST-0135.R1_Proof_hi.pdf