What Is A Linear Correlation Coefficient Factor Is Measured Between The Peak Area Used?

Linearity: A linear correlation coefficient factor was obtained between the peak area used and the absorbance Verses concentrations of lamivudine, zidovudine and nevirapine. The calibration curves were linear for concentrations between 15-150 µg/ml. The linearity of the calibration curves was validated by the values of the correlation coefficients (r2). The correlation coefficients were 0.999 for lamivudine, 0.999 zidovudine and 0.999 for nevirapine. The results of the linearity experiment are listed in Table 4.Linearity graphs were shown in Figure 3
Accuracy (% recovery): The accuracy parameter conducted by using the standard addition method. The proposed method afforded a recovery of 99.49–101.54% after the additional standard drug solution
Formulation drug products were exposed to thermal stress, hydrolytic stress under basic and acidic medium and oxidative stress. An ideal stability indicating method is one that quantifies the standard drug alone and also resolves its degradation products. So described, different types of stress were used thermal, oxidation,base hydrolysis and acid hydrolysis. Although unknown degradant peaks were observed in the acid, base, peroxide and thermal study, no degradant peaks were reported in the retention time(Rt) of lamivudine, zidovudine and nevirapine. Therefore, lamivudine, zidovudine and nevirapine are stable up to specified period (12 h) when the proposed method is used, or they are susceptible to acids, alkali, heat and hydrogen
The % drug degradations observed were 5.00%, 8.03% and 20.69% for lamivudine, zidovudine and nevirapine (Table 9), here in acidic medium nevirapine is more degrade than lamivudine and zidovudine. Here no degradant peaks were observed in the retention time (Rt) of lamivudine, zidovudine and nevirapine (Figure 4a).
Degradation of lamivudine, zidovudine and nevirapine in 0.1 N NaOH (alkali conditions) at room temperature (RT) for 6hrs under reflux conditions: The results showed multiple peaks for the degradation products. The % drug degradations observed were 14.39%, 13.73% and 16.66% for lamivudine, zidovudine and nevirapine (Table 9), here in alkali medium nevirapine is more degrade than lamivudine and zidovudine. Here no degradant peaks were observed, at the retention time (Rt) of lamivudine, zidovudine and nevirapine (Figure