สารบัญ

Thai name  น้ำมันผิวส้ม (NAMMAN PHIU SOM)

Category  Pharmaceutic aid.

        Orange Oil is obtained by mechanical means from the fresh peel of the fruit of Citrus sinensis (L.) Osbeck (Family Rutaceae).  It contains not less than 1.0 per cent w/w of aldehydes, calculated as decanal, C₁₀H₂₀O. 

Origin of plant  Orange Oil-yielding plant is possibly not a naturally occurring species.  According to the genetic analysis evidence, most experts agree that the plant is a hybrid originated by an intentional cross between Citrus reticulata Blanco and Citrus maxima (Burm.) Merr.  It is, however, believed to be originally found near the border between China and Vietnam, and is cultivated across the subtropical and tropical regions, as well as Florida, California, and Brazil.

Constituents  Orange Oil contains predominantly limonene.  It also contains other monoterpenoids, e.g., α-pinene, β-pinene, β-myrcene, sabinene, and linalool.

Description  Yellow to yellowish brown liquid, visibly free from water; odour, that of orange.

Other relevant information  It shall not be used if it has terebinthine odour.

Packaging and storage  Orange Oil shall be kept in well-filled, tightly closed containers, protected from light, and stored at a temperature not exceeding 25°.

Solubility test  Soluble, at 20°, in 7 volumes of ethanol (90 per cent).

Weight per millilitre  0.842 to 0.848 g (Appendix 4.9).

Refractive index  1.472 to 1.476, at 20º (Appendix 4.7).

Optical rotation  +94° to +99° (Appendix 4.8).

Residue on evaporation  1.0 to 5.0 per cent w/w when determined by the method for “Residue on Evaporation of Volatile Oils” (Appendix 7.13).  Use 2 g and heat for 4 hours.

Assay  Carry out the method for the “Determination of Aldehydes” (Appendix 7.9), using 10 g, omitting the toluene and using a volume, not less than 7 mL, of hydroxylamine in ethanol (60 per cent) TS that exceeds by 1 to 2 mL the volume of 0.5 M potassium hydroxide in ethanol (60 per cent) VS required.  Each mL of 0.5 M potassium hydroxide in ethanol (60 per cent) VS is equivalent to 78.76 mg of C₁₀H₂₀O.