Abstract

FORMULATIONANDEVALUATIONOFCLOPIDOGRELNIOSOMES

K.V.N.R. Aishwarya, K.N.V. Kiranmayi*, K. Gangaprasad, K. Sneha, K. Satish and K. Sanjeev

ABSTRACT

The objective of present study is to formulate and evaluate niosomes of Clopidogrel for controlled release application. Clopidogrel niosomes were prepared by ethanol injection method employing cholesterol and surfactant in 1:1 ratio. The formulated niosomes were evaluated for Average particle size distribution, Entrapment efficiency, Estimation of drug content and Drug release study. All the clopidogrel niosomes prepared were found to be discrete, spherical and free flowing. The size of niosomes was 12/16 mesh (1435μm). The drug content and micro encapsulation efficiency of various microspheresprepared are given in table. 2. Low c. v. values (< 2.25 %) in the drug content ensured uniformity of the drug content in the niosomes prepared. The microencapsulation efficiency was in the range 73.6 % with various niosomes. Clopidogrel release from the niosomes prepared was studied in distilled water. The drug release profiles of various microspheresprepared are shown in Table 3 and in Figs.1-4. The drug release parameters are given in Table 4. Clopidogrel release from all the niosomes prepared was slow and spread for 10 h. The relationship could be expressed by the linear equation, Y= -0.007X+0.807 (R2=0.981), where Y is release rate (K1) and X is percent coat in the niosomes. As such drug release rate from the niosomes can be controlled by varying the percent coat. The drug release data were analyzed as per zero order, first order, Higuchi and Korsmeyer-Peppaskinetic equation modelsto assessthe release kineticsand mechanism. The coefficient of determination values (R2) observed in the analysisof release data asper various kinetic models are shown in Table 3. The R2 values were higher in the first order model than those in the zero order model indicating that the drug release from the niosomes prepared followed first order kinetics. The first order drug release profiles of variousniosomesprepared are shown in Fig. 2. Drug release data also obeyed Higuchi and Korsmeyer-Peppas equation models with R2 > 0.930. The Higuchi plot (Fig.3), were found to be linear indicating diffusion controlled drug release from the niosomesprepared. When the release data were analyzed as per Korsmeyer-Peppas (Fig.4) equation, the release exponent ‘n’ was 0.937 indicating non-fickian diffusion asthe release mechanism from the clopidogrel niosomesprepared.

Keywords: Niosomes, Clopidogrel, Ethanol injection method, Entrapment efficiency.