Orthophosphoric acid

All the chemicals used were of analytical reagent grade, and the solvents were of HPLC grade. Indacaterol maleate and glycopyrronium bromide reference substances were kindly provided by Novartis (Basel, Switzerland). Tenoxicam (TNX) as internal standard and maleic acid were obtained from Sigma Chemicals. Inhaler capsules containing 110 µg of IND and 50 µg of GLY/capsule (Ultibro^® Breezhaler^®), 150 µg of IND/capsule (Onbrez Breezhaler^®) and 50 µg of GLY/capsule (Seebri^® Breezhaler^®) were obtained from commercial sources. Acetonitrile and methanol were purchased from Sigma-Aldrich (Germany). Orthophosphoric acid (85% w/v) was obtained from Riedel-deHaën (Sleeze, Germany). Hydrochloric acid (32% w/v), hydrogen peroxide (10% w/v), sodium hydroxide and sodium dihydrogen phosphate were obtained from Adwic Co. (Cairo, Egypt). High purity distilled water was used in the study.

All chromatographic solvents were of high-performance liquid chromatography (HPLC) grade. Ethanol, acetone, acetonitrile, mEthanol (≥99.9%), l-ascorbic acid, gallic acid, (+)-catechin, (−)-epicatechin, and quercetin were obtained from Sigma-Aldrich (Johannesburg, South Africa). quercetin-3-glucoside was obtained from Fluka (Buchs, Switzerland), malvidin-3-glucoside from Polyphenols Laboratories AS (Norway), and acetic acid and orthophosphoric acid from Riedel-de Haën (Seelze, Germany). Purified water was obtained from a Milli-Q filtration system (Millipore Filter Corp., Bedford, MA, USA).

All the chemicals used were of Analytical Reagent grade, and the solvents were of HPLC grade. Loratadine (certified purity 99.7%) and desloratadine (certified purity 99.6%) were kindly provided by Schering-Plough Co., USA. Sodium dodecyl sulfate (SDS) was obtained from Merck KGaA (Darmstadt, Germany). Triethylamine (TEA) and orthophosphoric acid, 85% were obtained from Riedel-de Haën (Seelze, Germany). Methanol, ethanol, n-propanol, n-Butanol and acetonitrile (HPLC grade) were obtained from Sigma-Aldrich (Germany).
Pharmaceutical preparations containing the studied drugs were purchased from the local Egyptian market. These include Loratadine 10 mg Tablets labeled to contain 10 mg of LOR (produced by Misr Company for Pharmaceutical Industries, Cairo, Egypt, batch#150103), Desa 5 mg Tablets labeled to contain 5 mg of DSL (produced by Delta Pharma Tenth of Ramadan City, Egypt, batch#31910).
The human plasma sample was kindly provided by Mansoura University Hospitals, Mansoura, Egypt and kept frozen at −5 °C until use after gentle thawing. Drug free urine sample was collected from a male healthy adult volunteer (30-years old). The breast milk sample was obtained from a female healthy volunteer (28-years old).