Lecithin

Triamcinolone acetonide was generously provided as a gift sample by Lupin Ltd. (Pune, India). Capmul MCM C10 (Glyceryl monocaprate), Transcutol^®P (diethylene glycol monoethyl ether), and Captex 200P (Propylene glycol dicaprate) were generously provided as free gift samples by ABITEC Corporation (Columbus, OH, USA). Lecithin was supplied as a generous gift by Lipoid GmbH (Ludwigshafen, Germany). Polysorbate 80 was purchased from Fischer Scientific Pvt Ltd. (Mumbai, India). Stearylamine was purchased from Sigma-Aldrich, St. Louis, MO, USA. LC-MS grade acetic acid (AA), formic acid (FA), acetonitrile and methanol were purchased from Merck (Darmstadt, Germany). Ultrapure water of a Milli-Q Gradient system (Millipore Corp., Bedford, MA, USA) was used for the study. All other chemicals and reagents were of analytical grade, while HPLC solvents were of HPLC grades.

Poloxamer-188 was purchased from Merck (Darmstadt, Germany). Diltiazem hydrochloride (DLZ), stearyl alcohol (STA), and hydroxypropyl methylcellulose (HPMC) were obtained from Thermo Fisher Scientific (Loughborough, UK). Tildiem^® (60 mg tablets) were ordered from Al Ain Pharmacy (Al Ain, UAE). Lecithin was acquired from Lipoid GmbH (Ludwigshafen, Germany). Sodium taurocholate (NaTC) and pepsin were obtained from Sigma Aldrich (St. Louis, MO, USA). Acetonitrile, 2−propanol, n-hexane, isopropyl alcohol, trimethylamine, ammonium dihydrogen phosphate, phosphoric acid, hydrochloric acid, glacial acetic acid, and sodium hydroxide were acquired from Merck (Darmstadt, Germany). All solvents used were of HPLC grade.

Gelucire^® 43/01 (mixtures of mono-, di- and triglycerides with PEG esters of fatty acids), glyceryl monostearate (GMS), Compritol^® 888 ATO (glycerol dibehenate/behenate) and Capryol^® PGMC (propylene glycol monocaprylate type I) were kindly gifted by Gattefosse (St Priest, Cedex, France). Pluronic^®F68 (polyoxyethylene-polyoxypropylene (150:29) block copolymer, poloxamer 188) was purchased from Sigma-Aldrich, Inc. (St. Louis, MO). AT (atorvastatin) is kindly gifted by Al-Arabiya Pharmaceutical Company (Cairo, Egypt). Lecithin (70% phosphatidylcholine) was kindly gifted by Lipoid (Ludwigshafen, Germany). Tween^® 80 (polyoxyethylen-80-sorbitanmonooleat, polysorbate 80) was purchased from ADWIC Chemicals Co. (Cairo, Egypt). All the reagents were of analytical grade and used without further purification.

Mylan Laboratories (Hyderabad, India) provided RTG as a gift sample. Glipizide, an internal standard (IS), was acquired from TCI Chemicals Pvt Ltd. (Chennai, India). Isoflurane USP was purchased from Abbott (Mumbai, India) for inhalation anesthesia. Medium-molecular-weight chitosan (75–85% deacetylated), acetic acid glacial was purchased from SISCO Research Laboratories (SRL) Pvt. Ltd. (Delhi, India). Lecithin (Lipoid S 100, soybean Lecithin with phosphatidylcholine) and Poloxamer 407 were obtained as gift samples from Lipoid (GmBH, Germany) and BASF (Mumbai, India), respectively. Sodium chloride, potassium chloride, mannitol, and different buffer salts (KH₂PO₄, K₂HPO₄) were acquired from SD Fine Chemicals Pvt. Ltd. (Mumbai, India). HPLC grade acetonitrile (ACN) was purchased from Merck (Mumbai, India). Milli-Q water was taken from a Milli-Q^® Reference water purification system (GmbH, Germany) and was used in all experimental procedures and analysis. Wistar rats were acquired from Central animal facility, BITS Pilani, Pilani, India. All the statistical analysis were performed using GraphPad Prism 7.0 (GraphPad software Inc., San Diego, CA, USA).

Sodium alginate was purchased from Sigma–Aldrich (CAS number 9005-38-3). Calcium chloride was purchased from Merck. Lecithin (phosphatidyl choline S75) was obtained as a gift sample from Lipoid. Tween 80 and Span 80 were purchased from Srichand United Dispensary.