Formulation And Evaluation Of Lipid Microparticle-Based Mosquito Repellent Cream

ABSTRACT

In the tropics, malaria has become the most alarming public health problem, hence the need

for a mosquito repellent, a personal protection against the vector. The concern about the

deleterious effects associated with synthetic chemicals like N, N-diethy-3-methylbenzamide

(DEET) has elicited the interest to explore plant materials as source of natural repellent for

mosquito control. The aim of this study was to formulate and evaluate herbal mosquito

repellent cream based on solid lipid microparticles (SLM). To determine the mosquito

repellent activity of Ocimum gratissimum ethanol extract and eucalyptus oil, SLM-based

creams containing various concentrations of Ocimum gratissimum and eucalyptus oil were

formulated and tested against three species of mosquito viz; Anopheles gambaiae, Aedes

aegypti and Culex quinquefasciatus. The SLM-based cream formulations were characterized

for their physicochemical (colour, texture, odour and stability) and rheological properties

(spreadability, oclusivity), particle size and pH. It was found that the repellent effect of the

creams was dependent on the concentration of the repellents. Also, the creams with Ocimum

gratissimum ethanol extract provided protection for up to two hours against Anopheles

gambaiae and Culex quinquefasciatus, while the creams with eucalyptus oil provided

protection for up to two hours against Anopheles gambaiae only.

On physical examination, the products were ‘cream’ coloured, smooth and aromatic for the

eucalyptus oil creams, and light green, smooth and of a characteristic odour for Ocimum

gratissimum extract creams. The mean value ± SD for the rheological properties of the creams

were, particle size; F = 10.40; p < 0.1, spreadability; F = 0.32; p > 0.05, occlusivity; F =

11.81; p < 0.01 and pH; F = 2.89; p > 0.05.