Span 40

Cetyl palmitate, isopropyl palmitate, and
caprylic/capric triglycerides were purchased from the Namsiang Group
(Bangkok, Thailand). Oleic acid, stearic acid, Tween80 (Polysorbate
80), and Span40 (Sorbitan monopalmitate) were purchased from Sigma-Aldrich
(Japan). Distilled water and deionized water were prepared freshly
using an Autostil 8000× (England) and aquaMax-Ultra (Korea),
respectively. All other chemicals used were commercial products of
analytical grade. The materials were used without further purification.

Lidocaine hydrochloride, Span^® 60, SPAN^® 40, and Diacetyl phosphate (DCP) were purchased from Sigma-Aldrich Co (St. Louis, MO, USA). Prilocaine hydrochloride was purchased from UTRC (Toronto, ON, Canada). Disodium hydrogen phosphate was purchased from R&M Chemicals (Essex, UK). Sodium dihydrogen phosphate anhydrous was purchased from QReC (Selangor, Malaysia). Sodium hydroxide was purchased from Sharlau Chemie (S.A, Barcelona, Spain). Cholesterol, 95% stabilized, was purchased from Acros Organics (Fair Lawn, NJ, USA). Acetonitrile and chloroform were purchased from Fisher Scientific (Fair Lawn, NJ, USA). Labrasol was purchased from Gattefosse (Cedex, France). Propylene glycol was purchased from Dow Chemical (Thailand). Hamin-C^® palm oil base was purchased from Oleopharma Sdn. Bhd., (Malaysia). Acrylates/C10–30 Alkyl Acrylate Crosspolymer was purchased from Lubrizol (Clifton, NJ, USA). Strat M™ membrane was purchased from Merck (Darmstadt, Germany).

Clarithromycin was obtained as a gift sample from the JOSWE Pharmaceutical Company (Amman, Jordan). Phosphoric acid was purchased from RomiL™ (Cambridge, UK), while HPLC-grade acetonitrile and HPLC-grade methanol were purchased from Tedia™ (Fairfield, OH, USA). Span™ 40, Span™ 60, Span™ 80, Tween™ 60, Tween™ 80, and cholesterol (Chol) were purchased from Sigma Aldrich™ (Gillingham, Dorset, UK). Diethyl ether and methanol were purchased from Tedia™ (Fairfield, OH, USA). Cellulose dialysis membranes with a molecular weight cut-off (MWCO) of 12–14 kDa, average flat width of 28.46 mm, and average diameter of 17.5 mm were purchased from HiMedia Laboratories™ (Mumbai, Maharashtra, India). Polyethylene glycol 400 (PEG 400) was purchased from GCC Diagnostics™ (Deeside, Flintshire, UK). Hydroxypropyl methyl cellulose (HPMC) 40,000, dicetyl phosphate (DCP), and phosphate-buffered saline (PBS) tablets were purchased from Sigma Aldrich™ (Gillingham, Dorset, UK). All other chemicals used in this study were of analytical grade.

Zolmitriptan was kindly supplied and certified by Global Nabi Pharmaceuticals (GNP), 6th of October, Giza, Egypt (Batch number: ZT 18040001). Brij^® 35 (polyoxyethylene (23) lauryl ether), Brij^® O10 (polyoxylethylene (10) oleyl ether), cholesterol, hydroxypropyl methylcellulose (HPMC) (viscosity 1500–4500 cp at 37 °C), poloxamer 407, sodium deoxycholate, Span^® 20 (sorbitan monolaurate), Span^® 40 (sorbitan monopalmitate), Span^® 60 (sorbitan monostearate), Span^® 80 (sorbitan monooleate), Tween^® 65 (polyoxyethylene sorbitan tristearate), Tween^® 80 (polyoxyethylene sorbitan monooleate) and dialysis tubing cellulose membrane (molecular weight cutoff 14,000 g/mol) were procured from Sigma-Aldrich, St. Louis, MO, USA. Methylene blue was obtained from El-Nasr Pharmaceutical Chemicals Company, Abu-Zaabal, Cairo, Egypt. Normal saline was purchased from Otsuka Pharmaceutical Co., Egypt. Acetonitrile and formic acid (both of HLPC grade) were supplied by Romil Limited, London, UK and E. Merk, D-6100 Darmstadt, Germany, respectively. Torsemide was provided and certified by DELTA Pharma, Cairo, Egypt. The water used was distilled de-ionized water. The other chemicals were of reagent grade and used as provided.