In Vitro–In Vivo Correlation in Dermal Delivery: The Role of Excipients

The composition of topical and transdermal formulations is known to determine the rate and the extent of drug delivery to and through the skin. However, to date, the role of excipients in these formulations on skin delivery of actives has received little attention from scientists in the field. Monit...

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Main Authors: Avnish Patel, Fotis Iliopoulos, Peter J. Caspers, Gerwin J. Puppels, Majella E. Lane
Format: Article
Language:English
Published: MDPI AG 2021-04-01
Series:Pharmaceutics
Subjects:
Online Access:https://www.mdpi.com/1999-4923/13/4/542
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author Avnish Patel
Fotis Iliopoulos
Peter J. Caspers
Gerwin J. Puppels
Majella E. Lane
author_facet Avnish Patel
Fotis Iliopoulos
Peter J. Caspers
Gerwin J. Puppels
Majella E. Lane
author_sort Avnish Patel
collection DOAJ
description The composition of topical and transdermal formulations is known to determine the rate and the extent of drug delivery to and through the skin. However, to date, the role of excipients in these formulations on skin delivery of actives has received little attention from scientists in the field. Monitoring skin absorption of both drug and vehicle may provide insights into the mechanism by which excipients promote permeation and may facilitate the design of effective and safer products. Previously, we have investigated the use of quantitative Confocal Raman Spectroscopy (CRS) to investigate the delivery of an active to the skin, and we also reported the first fully quantitative study that compared this method with the well-established in vitro permeation test (IVPT) model. To further explore the potential of quantitative CRS in assessing topical delivery, the present work investigated the effects of commonly used excipients on the percutaneous absorption of a model drug, ibuprofen (IBU). Permeation of IBU and selected solvents following finite dose applications to human skin was determined in vitro and in vivo by Franz diffusion studies and quantitative CRS, respectively. The solvents used were propylene glycol (PG), dipropylene glycol (DPG), tripropylene glycol (TPG), and polyethylene glycol 300 (PEG 300). Overall, the cumulative amounts of IBU that permeated at 24 h in vitro were similar for PG, DPG, and TPG (<i>p</i> > 0.05). These three vehicles outperformed PEG 300 (<i>p</i> < 0.05) in terms of drug delivery. Concerning the vehicles, the rank order for in vitro skin permeation was DPG ≥ PG > TPG, while PEG 300 did not permeate the skin. A linear relationship between maximum vehicle and IBU flux in vitro was found, with a correlation coefficient (R<sup>2</sup>) of 0.95. When comparing in vitro with in vivo data, a positive in vitro–in vivo (IVIV) correlation between the cumulative permeation of IBU in vitro and the total amount of IBU that penetrated the stratum corneum (SC) in vivo was observed, with a Pearson correlation coefficient (R<sup>2</sup>) of 0.90. A strong IVIV correlation, R<sup>2</sup> = 0.82, was found following the linear regression of the cumulative number of solvents permeated in vitro and the corresponding skin uptake in vivo measured with CRS. This is the first study to correlate in vivo permeation of solvents measured by CRS with data obtained by in vitro diffusion studies. The IVIV correlations suggest that CRS is a powerful tool for profiling drug and vehicle delivery from dermal formulations. Future studies will examine additional excipients with varying physicochemical properties. Ultimately, these findings are expected to lead to new approaches for the design, evaluation, and optimization of formulations that target actives to and through the skin.
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spelling doaj.art-f866b4957ce24cc196e41f830f0e66ce2023-11-21T15:21:15ZengMDPI AGPharmaceutics1999-49232021-04-0113454210.3390/pharmaceutics13040542In Vitro–In Vivo Correlation in Dermal Delivery: The Role of ExcipientsAvnish Patel0Fotis Iliopoulos1Peter J. Caspers2Gerwin J. Puppels3Majella E. Lane4Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UKDepartment of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UKRiverD International B.V., Marconistraat 16, 3029 AK Rotterdam, The NetherlandsRiverD International B.V., Marconistraat 16, 3029 AK Rotterdam, The NetherlandsDepartment of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UKThe composition of topical and transdermal formulations is known to determine the rate and the extent of drug delivery to and through the skin. However, to date, the role of excipients in these formulations on skin delivery of actives has received little attention from scientists in the field. Monitoring skin absorption of both drug and vehicle may provide insights into the mechanism by which excipients promote permeation and may facilitate the design of effective and safer products. Previously, we have investigated the use of quantitative Confocal Raman Spectroscopy (CRS) to investigate the delivery of an active to the skin, and we also reported the first fully quantitative study that compared this method with the well-established in vitro permeation test (IVPT) model. To further explore the potential of quantitative CRS in assessing topical delivery, the present work investigated the effects of commonly used excipients on the percutaneous absorption of a model drug, ibuprofen (IBU). Permeation of IBU and selected solvents following finite dose applications to human skin was determined in vitro and in vivo by Franz diffusion studies and quantitative CRS, respectively. The solvents used were propylene glycol (PG), dipropylene glycol (DPG), tripropylene glycol (TPG), and polyethylene glycol 300 (PEG 300). Overall, the cumulative amounts of IBU that permeated at 24 h in vitro were similar for PG, DPG, and TPG (<i>p</i> > 0.05). These three vehicles outperformed PEG 300 (<i>p</i> < 0.05) in terms of drug delivery. Concerning the vehicles, the rank order for in vitro skin permeation was DPG ≥ PG > TPG, while PEG 300 did not permeate the skin. A linear relationship between maximum vehicle and IBU flux in vitro was found, with a correlation coefficient (R<sup>2</sup>) of 0.95. When comparing in vitro with in vivo data, a positive in vitro–in vivo (IVIV) correlation between the cumulative permeation of IBU in vitro and the total amount of IBU that penetrated the stratum corneum (SC) in vivo was observed, with a Pearson correlation coefficient (R<sup>2</sup>) of 0.90. A strong IVIV correlation, R<sup>2</sup> = 0.82, was found following the linear regression of the cumulative number of solvents permeated in vitro and the corresponding skin uptake in vivo measured with CRS. This is the first study to correlate in vivo permeation of solvents measured by CRS with data obtained by in vitro diffusion studies. The IVIV correlations suggest that CRS is a powerful tool for profiling drug and vehicle delivery from dermal formulations. Future studies will examine additional excipients with varying physicochemical properties. Ultimately, these findings are expected to lead to new approaches for the design, evaluation, and optimization of formulations that target actives to and through the skin.https://www.mdpi.com/1999-4923/13/4/542ibuprofenexcipientsskin deliveryConfocal Raman Spectroscopyin vitro–in vivo correlation
spellingShingle Avnish Patel
Fotis Iliopoulos
Peter J. Caspers
Gerwin J. Puppels
Majella E. Lane
In Vitro–In Vivo Correlation in Dermal Delivery: The Role of Excipients
Pharmaceutics
ibuprofen
excipients
skin delivery
Confocal Raman Spectroscopy
in vitro–in vivo correlation
title In Vitro–In Vivo Correlation in Dermal Delivery: The Role of Excipients
title_full In Vitro–In Vivo Correlation in Dermal Delivery: The Role of Excipients
title_fullStr In Vitro–In Vivo Correlation in Dermal Delivery: The Role of Excipients
title_full_unstemmed In Vitro–In Vivo Correlation in Dermal Delivery: The Role of Excipients
title_short In Vitro–In Vivo Correlation in Dermal Delivery: The Role of Excipients
title_sort in vitro in vivo correlation in dermal delivery the role of excipients
topic ibuprofen
excipients
skin delivery
Confocal Raman Spectroscopy
in vitro–in vivo correlation
url https://www.mdpi.com/1999-4923/13/4/542
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AT fotisiliopoulos invitroinvivocorrelationindermaldeliverytheroleofexcipients
AT peterjcaspers invitroinvivocorrelationindermaldeliverytheroleofexcipients
AT gerwinjpuppels invitroinvivocorrelationindermaldeliverytheroleofexcipients
AT majellaelane invitroinvivocorrelationindermaldeliverytheroleofexcipients