eprintid: 10091121 rev_number: 28 eprint_status: archive userid: 608 dir: disk0/10/09/11/21 datestamp: 2020-02-18 11:39:15 lastmod: 2021-10-09 22:42:06 status_changed: 2020-02-18 11:39:15 type: article metadata_visibility: show creators_name: Iliopoulos, F creators_name: Sil, B creators_name: Al-Hossain, ASMM creators_name: Moore, D creators_name: Lucas, R creators_name: Lane, M title: Topical delivery of niacinamide: influence of neat solvents ispublished: pub divisions: UCL divisions: B02 divisions: C08 divisions: D10 divisions: G08 keywords: In vitro, porcine skin, permeation, finite dose, niacinamide note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: Niacinamide (NIA) has been widely used in cosmetic and personal care formulations for several skin conditions. Permeation of topical NIA has been confirmed in a number of studies under infinite dose conditions. However, there is limited information in the literature regarding permeation of NIA following application of topical formulations in amounts that reflect the real-life use of such products by consumers. The aim of the present work was therefore to investigate skin delivery of NIA from single solvent systems in porcine skin under finite dose conditions. A secondary aim was to probe the processes underlying the previously reported low recovery of NIA following in vitro permeation and mass balance studies. The solubility and stability of NIA in various single solvent systems was examined. The solvents investigated included Transcutol® P (TC), propylene glycol (PG), 1-2 hexanediol (HEX), 1-2 pentanediol (1-2P), 1-5 pentanediol (1-5P), 1-3 butanediol (1-3B), glycerol (GLY) and dimethyl isosorbide (DMI). Skin permeation and deposition of the molecule was investigated in full thickness porcine skin in vitro finite dose Franz-type diffusion experiments followed by mass balance studies. Stability of NIA for 72 h in the solvents was confirmed. The solubility of NIA in the solvents ranged from 82.9 ± 0.8 to 311.9 ± 4.5 mg/mL. TC delivered the highest percentage permeation of NIA at 24 h, 32.6 ± 12.1 % of the applied dose. Low total recovery of NIA after mass balance studies was observed for some vehicles, with values ranging from 55.2 ± 12.8 % to 106.3 ± 2.3 %. This reflected the formation of a number of NIA degradation by-products in the receptor phase during the permeation studies. Identification of other vehicles for synergistic enhancement of NIA skin delivery will be the subject of future work. date: 2020-04-15 date_type: published publisher: Elsevier official_url: https://doi.org/10.1016/j.ijpharm.2020.119137 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1752512 doi: 10.1016/j.ijpharm.2020.119137 lyricists_name: Iliopoulos, Fotis lyricists_name: Lane, Majella lyricists_id: FILIO03 lyricists_id: MLANE69 actors_name: Lane, Majella actors_id: MLANE69 actors_role: owner full_text_status: public publication: International Journal of Pharmaceutics volume: 579 article_number: 119137 citation: Iliopoulos, F; Sil, B; Al-Hossain, ASMM; Moore, D; Lucas, R; Lane, M; (2020) Topical delivery of niacinamide: influence of neat solvents. International Journal of Pharmaceutics , 579 , Article 119137. 10.1016/j.ijpharm.2020.119137 <https://doi.org/10.1016/j.ijpharm.2020.119137>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10091121/1/1-s2.0-S0378517320301216-main.pdf