Ethyl alcohol ethanol

Paraffin oil (Merck KGOA, Darmstadt, Germany), acetyl alcohol (St. Louis, MO, USA), span 80 (Sigma-Aldrich, Darmstadt, Germany), 2,2-diphenyl-1-picrylhydrazyl (DPPH) (Sigma-Aldrich, Darmstadt, Germany), propyl paraben (Sigma-Aldrich, Darmstadt, Germany), Tween 80 (Sigma-Aldrich, Darmstadt, Germany), propylene glycol (Sigma-Aldrich, Darmstadt, Germany), methyl paraben (Sigma-Aldrich, Darmstadt, Germany), ethyl alcohol (Ethanol) (Sigma-Aldrich, Darmstadt, Germany), carbopol-940 (Sigma-Aldrich, St. Louis, MO, USA), triethanol amine (TEA) (Sigma-Aldrich, Darmstadt, Germany) were used in this research work. Purified water was manufactured at the laboratory of cosmeceuticals, Department of Pharmacy, IUB, Pakistan. Rotary evaporator (Heidolph, Co., Ltd., Schwabach, Germany, Bioevopeak Inc., Seattle, WA, USA), UV spectrophotometer (Boschaplatz 3 Presseck, 95355 Germany), microplate reader Synergy HT (BioTek Instrument, Stevens Creek Blvd, Santa Clara, CA, USA), refrigerator (Dawlance, Karachi, Pakistan), hot incubator (Sanyo MIR-162, Moriguchi City, Japan), digital humidity meter (TES Electronic Corp., Taipei, Taiwan), pH meter (WTW pH-197i, Weilheim, Germany), optical microscope (Eclipse E200, Nikon, Melville, NY, USA), and conductivity meter (WTW COND-197i, Weilheim, Germany) were used.

For the preparation of the pH-sensitive colorimetric assay, bromothymol blue (CAS no. 76-59-5), methyl red (CAS no. 493-52-7), sodium hydroxide (CAS no. 1310-73-2), ethyl alcohol (ethanol) (CAS no. 64-17-5), sodium phosphate monobasic monohydrate (CAS no. 10049-21-5) and sodium phosphate dibasic (CAS no. 7558-79-4) were purchased from Sigma-Aldrich (Canada). For the preparation of the nitrite colorimetric assay, N-1-naphthylethylenediamine dihydrochloride (NED) (CAS no. 1465-25-4), sulfanilamide (CAS no. 63-74-1) and sodium nitrite (CAS no. 7632-00-0) were purchased from Sigma (Sigma-Aldrich, Canada).