SIMULTANEOUS ESTIMATION OF TEA TREE OIL AND NEEM SEED OIL IN BULK AND COSMECEUTICAL FORMULATION BY UV SPECTROPHOTOMETRY

Tea tree oil, an essential oil, has claims for analgesic, antimicrobial, antiseptic, and anti-inflammatory activity. Its complex composition is governed by ISO 4730:2017. It is extensively used in skin and hair care cosmeceuticals, often in combination with neem seed oil. Neem seed oil has potent antimicrobial, skin rejuvenating, and conditioning action attributed to the presence of micro constituents and complex lipid composition of triglycerides, diglycerides, and monoglycerides of both saturated and unsaturated fatty acids. Although few methods are available for estimation of individual oils, simple spectrophotometric methods suitable for routine determination of either oil or for simultaneous estimation of both the oils are not reported. A novel, simple, validated UV spectrophotometric method for simultaneous estimation of tea tree oil and neem seed oil in bulk and cosmeceutical formulation has been developed after optimization and validation of UV spectrophotometric method for individual estimation of oils. The method relies on the measurement of absorbance at 267nm and 284nm, λ_max of tea tree oil, and neem seed oil, respectively. Linearity is established over a concentration range of 20-160mcg/ml and 0.2-2.0mg/ml for tea tree oil and neem seed oil, respectively. Recovery results are in the range of 101.3-109.8% for neem seed oil and 60.0-69.2% for tea tree oil, respectively. Percent relative standard deviation values for precision, robustness and ruggedness is less than 2%. The validated method confirmed to ICH: Q2 (R1) guidelines and was successfully applied for determining the oil content of a marketed face wash product containing both the actives.