Dulbecco a tablets

IBU was a gift from Wyeth (Haversham, Hants, UK). PEG 300, PG, isopropyl alcohol (IPA), and trifluoroacetic acid (TFA) were supplied by Fisher Scientific (Leicestershire, UK). TPG, methanol, and High Performance Liquid Chromatography (HPLC) grade water were supplied by Sigma-Aldrich (Dorset, UK). DPG was supplied by Acros Organics (Fisher Scientific, Leicestershire, UK). Phosphate buffered saline (pH 7.4) was prepared using Dulbecco A tablets purchased from Oxoid Limited (Cheshire, UK). Excised abdominal human skin was obtained from the UK Human Tissue Bank and was stored at −20 °C until required (Research Ethics Committee reference 06/MRE04/37). The epidermis was separated by the heat separation method according to procedures reported previously [36 (link)].

Amitriptyline hydrochloride (AMI-HCl), Brij™ O20, dichloromethane (DCM), anhydrous acetone, and sodium carbonate were obtained from Sigma-Aldrich (UK). Sodium dihydrogen phosphate, sodium hydrogen phosphate, magnesium sulphate, and dithiothreitol (DTT) were supplied by Fisher Scientific (UK). Phosphate-buffered saline (pH 7.3 ± 0.2 at 25 °C) was prepared using Dulbecco A tablets supplied by Oxoid (UK). Octyl salicylate (OSAL), PG, IPM, IPA, and 1-octanol were obtained from Sigma-Aldrich (UK). High-performance liquid chromatography (HPLC) grade water, HPLC grade acetonitrile, HPLC grade methanol, liquid chromatography/mass spectrometry (LC-MS) grade acetonitrile, LC-MS grade 0.1% trifluoroacetic acid (TFA) solution, limonene (LIM), ethyl acetate (EtAc), and TFA were supplied by Fisher Scientific (UK). Chloroform-d (CDCl₃) were obtained from Cambridge Isotope Laboratories Inc. (UK). Propylene glycol monolaurate (PGML) Type II and TC were gifts from Gattefossé (St. Priest, France). All chemicals, unless otherwise stated, were ≥ 99% purity.

Methadone hydrochloride, triPropylene glycol (TriPG), diPropylene glycol (DiPG), 1-octanol, 1,3-butanediol (1,3-BD), Brij™ O20, isopropyl myristate (IPM), octyl salicylate (OSAL), oleic acid (OA) and ethyl oleate (EO) were purchased from Sigma-Aldrich, Dorset, UK. Propylene glycol (PG), ethyl acetate, d-limonene (LIM), high performance liquid chromatography (HPLC) grade water, acetonitrile, orthophosphoric acid, 85+%, sodium dihydrogen phosphate, sodium hydrogen phosphate and sodium hydroxide were supplied by Fisher Scientific, Loughborough, UK. Chloroform-d (CDCl₃) was purchased from Cambridge Isotope Laboratories Tewksbury, MA, USA. Labrafac™ lipophile WL 1349 (medium-chain triglycerides of caprylic and capric acids, WL 1349), Transcutol^® (TC), Propylene glycol monocaprylate (PGMC) Type II and Propylene glycol monolaurate (PGML) Type II were gifts from Gattefossé, St. Priest, France. Phosphate buffered saline (PBS) (pH 7.3 ± 0.2 at 25 °C) was prepared using Dulbecco A tablets supplied by Oxoid, Cheshire, UK. Full thickness porcine ear skin was obtained from a local abattoir.