ABSTRACT:In this study, central composite design (CCD) was used for optimization of high performance liquid chromatographic (HPLC) method for simultaneous analysis of curcumin (CUR) and demethoxycurcumin (DMC) in tablets containing Curcuma extract. Separation of CUR and DMC was performed using X-Bridge C18 column (250 x 4.6 mm i.d; 5 µm). Four factors that were investigated include the concentration of acetic acid (X1), ratio of acetic acid (X2), flow rate of mobile phase (X3) and column temperature (X4). Based on responses obtained (retention time, peak area, resolution and tailing factor), the optimum condition selected was X1 = 3.00%, X2 = 51%, X3 = 1.05 mL/min and X4 = 45oC. This HPLC condition was validated by assessing several validation parameters including system suitability test, selectivity, linearity, precision, accuracy and robustness according to International Conference Harmonization (ICH). All validation parameters meet the acceptance criteria set by ICH. The validated method was successfully used for analysis of CUR and DMC in tablets containing Curcuma extract. CCD was effective means in optimization of HPLC for analysis of CUR and DMC in pharmaceutical formulation.

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Because thin-layer chromatography can be affected by climatic conditions, we investigated the impact of high temperatures (33-38 degrees C) and high relative humidities (80-100%) on the applicability of Toxi-Lab thin-layer chromatographic systems for the screening of basic and neutral drugs during a 6-month climatological cycle in Jakarta, Indonesia that can be characterized as hot and humid. In general, the Rf values as observed on the plate showed substantial deviations from those in the literature obtained in moderate climates. Most substances gave higher Rf values, and the deviations (sometimes amounting to 20 Rf units) increased with increasing humidities. However, when the observed Rf values were corrected by means of a reference mixture of standard drugs that was run on each plate, much better accuracy and reproducibility were obtained. Thus, these corrected Rcf values were compatible with the existing databases developed in temperate climates. These results are in line with earlier studies carried out under hot and dry conditions. In the earlier studies, the observed Rf values tended to be lower than those present in other databases, but here too, the Rf correction procedure corrected this phenomenon.