Formulation development and evaluation of Zidovudine sustained release tablets using 32 factorial design

The main objective of present investigation is to formulate the sustained release tablet of Zidovudine using 3 2 factorial design. Zidovudine, antiretroviral drug belongs to BCS Class I. The SR tablets of Zidovudine were prepared employing different concentrations of Carboplol974P and Xanthan gum in different combinations as a rate retardants by Direct Compression technique using 32 factorial design. The quantity of rate retarders, Carboplol974P and Xanthan gum required to achieve the desired drug release was selected as independent variables, X1 and X2 respectively whereas, time required for 10% of drug dissolution (t10%), 50% (t50%), 75% (t75%) and 90% (t90%) were selected as dependent variables. Totally nine formulations were designed and are evaluated for hardness, friability, thickness, % drug content, In-vitro drug release. From the Results it was concluded that all the formulation were found to be with in the Pharmacopoeial limits and the In-vitro dissolution profiles of all formulations were fitted in to different Kinetic models, the statistical parameters like intercept (a), slope (b) & regression coefficient (r) were calculated. Polynomial equations were developed for t10%, t50%, t75%, t90%. Validity of developed polynomial equations were verified by designing 2 check point formulations(C1, C2). According to SUPAC guidelines the formulation (F5) containing combination of 5% Carboplol974P and 5% Xanthan gum, is the most similar formulation (f2=85.04 & No significant difference, t= 0.20046) to marketed product (Retrovir). The selected formulation (F5) follows Higuchi’s kinetics, the mechanism of drug release was found to be Case-II transport or typical Zero order release (Non-Fickian, n= 0.915).

Author(s): Raghavendra Kumar Gunda and J. N. Suresh Kumar

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