[High performance liquid chromatography-validated analytical method for 1% permethrin quantification]

In Cuba, as well as in other countries, Pediculus capitis infestation has increased since the 70's; this is the reason why a program aimed at controlling and preventing this infestation was designed. This program includes quality control studies of the active synthetic pyrethroid Permethrin and its activity at 1% on lice and 5% on scabies. Due to its low toxicity and positive risk/benefit ratio, Permethrin is a pediculicide of choice to decrease Pediculus capitis infestation.

To validate an analytical method using high performance liquid chromatography and its application in the quantification of 12 samples from 2 batches of Cuban-made 1% permethrin pediculicidal preparation.

Linearity, precision and accuracy parameters were determined. Seven calibration standards and working solutions with concentrations ranging from 100 to 15000 microg/mL were prepared. These validation parameters were verified through the correlation coefficient, the variation coefficient and the percentage relative error.

The specificity of this method was proved in the chromatograms that showed retention times of 8,8 to 9,2 min for the isomer trans and 10,7 to 11,2 min for the isomer cis. The correlation coefficient for both isomers was higher than 0,99; the variation coefficient was under 3% and the percentage relative error was--3 and 1% for the inter-day and intraday studies, respectively. The mean permethrin concentration in 1% solution batches was estimated at 6 780,14 microg/mL.

The validated method was linear, precise and exact within the range of the studied concentrations. The estimated concentration of permethrin was below the expected rate according to the composition of 1% permethrin solution (9 100-10 900 microg/mL). This method may be useful for the quantification of 1% permethrin solutions in the quality studies of the product sold to the population.