CHAPTER - 3 ANALYTICAL PROFILE 3.1 Estimation of Drug in Pharmaceutical Formulation 3.1.1 Estimation of Drugs
ANALYTICAL PROFILE 84 3.1 ESTIMATION OF DRUG IN PHARMACEUTICAL FORMULATION. Agrawal A et al (2010 )(111) reported simple, sensitive and selective RP-HPLC method with UV detection for the estimation of methotrexate in pharmaceutical formulation and in spiked plasma developed and validate in his work. Chromatographic separation of drug is performed with a 250X4.6 mm, 5µm diameter particles RP C-18 column and the mobile phase consisted of a mixture of methanol and water (80:20, v/v), containing 0.1% HPLC grade glacial acetic acid for the adjustment of ph to 4.5. Isocratic elution at a flow rate of 1 ml/min with UV detection at 256 nm at ambient temperature is used in this method. The proposed RP-HPLC method is successfully applied for the determination of MTX in pharmaceutical preparation and spiked plasma samples. Newbold PCH et al (1971) (112) reported affinity chromatography of dihydrofolate reductase and also UV visible method. Folate compounds were coupled in the following manner. A 50mg portion of the selected compound was suspended in 20ml of water and adjusted to ph 6.5 with 0.1nmMNaOH. Absorption spectra were obtained with a Unicam SP 1800B recording spectrophotometer, with as blanks the solutions described in the text. Floridia L et al (1999) (113) suggested high-performance liquid chromatography method for estimation of methotrexate for environmental monitoring of surface contamination in hospital departments and assessment of occupational exposure. Verma at el (2010) (114) developed sensitive and rapid spectrophotometric method for the assay of methotrexate in pharmaceutical formulations. The method is based on the absorption maximum of methotrexate at 302 nm and it obeys Beer s law in the concentration range of 5 30 µg/ml. An accurate, simple, sensitive and rapid extractive method for sildenafil citrate has been developed, the drug solution when treated with thymol blue solution in acidic medium, it forms a complex which is extracted in chloroform and its absorbance is measured at 413 nm, it obeys Beer s law in the
ANALYTICAL PROFILE 85 concentration of 12 to 72 µg / ml. A simple, sensitive and rapid extractive spectrophotometric estimation of trimetazidine dihydrochloride has been reported. The drug solution when treated with dye solution in the presence of acidic buffer solution, it forms coloured ion-pair complex which is easily extracted in chloroform. The absorbance is measured at 415 nm spectrophotometerically which obeys Beer s law in the concentration range of 5 25 µg/ml. All the results obtained in the study were validated statistically and by recovery studies. According to JP XV(2009) (115) an accurately weighed amount of doxorubicin hydrochloride and doxorubicin hydrochloride Reference Standard, equivalent to about 10 mg (potency), dissolve each in water to make exactly 25 ml. Five ml each of these solutions, was added to water to make exactly 100 ml, and used, as the sample solution and the standard solution, respectively. The absorbance s were determined at 495 nm, by ultraviolet-visible spectrophotometry. Yi-Mu et al (1999) (116) described UV spectrophotometric method for quantitative estimation of 5-FU. One hundred and five mg of 5-FU was weighed precisely, dissolved in thin HCl solution (9-1000) and adjusted to given volume. This solution was diluted to its half concentration. After 3.0, 6.0, 9.0, 12.0 and 15.0ml diluted solution were taken into 100ml volumetric flasks and adjusted to given volume respectively, their absorbance (A) values were detected on ultraviolet visible spectrophotometer at 265nm. The following regression equation was obtained: C=16.72±0.0416 (r=0.9998). In vitro release of the drug loaded doxorubicin was carried out by placing the dried and loaded nanoparticles in a test tube containing a definite volume (10ml) of phosphate buffer saline (PBS) as the drug release medium (ph 7.4). The amount of doxorubicin released from the polymeric nanoparticles was measured spectrophotometrically at 496nm and the released amount of drug was determined from calibration plot.
ANALYTICAL PROFILE 86 IP (1996) (117) incorporates another spectrophotometric method for determination of 5- FU. The acidic solution was extracted with chloroform filtered, diluted and absorbance was measured at maximum of 266nm. Degregorio MW et al (1985) (118) reported quantitative analysis of 5-fluorouracil in human serum by high-performance liquid chromatography analytical letter. 3.2 ESTIMATION OF DRUGS 3.2.1 Analytical method developed for Methotrexate Determination of absorption maxima Absorption maxima are the wavelength at which maximum absorption takes place. For accurate analytical work it is important to determine the absorption maxima of the substance under study. Method: UV Spectroscopic method Equipments: Shimadzu UV 1601 spectrophotometer Procedure: Ten mg of drug was dissolved in 10 ml of hydrochloric and acetate buffer (ph-2.0 and 4.0) further volume was made up to 100ml with buffer. From this solution 10ml was pipetted out and transferred into a 100ml volumetric flask, volume was made up to 100ml with respective buffer and from this solution pipetted out 10 ml in a test tube and subjected for UV-Vis scanning in the range 200-400nm. Preparation of calibration curve Method: UV Spectroscopic method Equipments: Shimadzu UV 1601 spectrophotometer Procedure: Accurately weighed 100mg of methotrexate was dissolved in different buffers (HCl buffer ph - 2.0 and acetate buffer ph 3.5) in a 100ml volumetric flask, diluted with buffer to volume & mixed. If necessary agitate gently for rapid dissolution. Twenty ml of this solution was pipetted out into a second 100ml volumetric flask, buffer was added to make volume & mixed. A set of standard dilutions of 2, 4, 6, 8, and 10µg/ml of drug were prepared by transferring aliquots of 0.1, 0.2, 0.3, 0.4, and 0.5ml of
ANALYTICAL PROFILE 87 stock solution (200µg/ml) in 10ml volumetric flask and volume make up to the mark with medium. The optical density values of resulting solutions were measured using 1cm cells at the wavelength of maximum absorbance using hydrochloric acid and acetate buffer as a blank and recorded in the table 3.1 and 3.2 with statistical data in table 3.3 and 3.4. The concentration versus absorbance values are plotted and given in figure 3.1 and 3.2 (119). Table 3.1: Calibration Curve Data And Regression Values Of Methotrexate at ph 2.0. Concentration (µg/ml) Absorbance (nm) 2 0.154±0.22 4 0.248±0.31 6 0.342±0.20 8 0.436±0.14 10 0.530±0.21 n = 3, all values ± standard deviation 0.6 0.5 Absorbance (nm) 0.4 0.3 0.2 0.1 0 2 4 6 8 10 12 Concentration (microgram/ml) Fig. 3.1 Standard Curve Of Methotrexate at ph 2.0
ANALYTICAL PROFILE 88 Table 3.2: Calibration Curve Data And Regression Values Of Methotrexate at 4.0. Concentration (µg/ml) Absorbance (nm) 2 0.089±0.19 4 0.237±0.21 6 0.385±0.16 8 0.534±0.22 10 0.682±0.16 n = 3, all values ± standard deviation 0.8 0.7 0.6 Absorbance (nm) 0.5 0.4 0.3 0.2 0.1 0.0 0 2 4 6 8 10 12 concentration (microgram/ml) Fig. 3.2 Standard Curve Of Methotrexate In Acetate Buffer at ph 4.0
ANALYTICAL PROFILE 89 Table 3.3: Statistical Data For Calibration Curve Of Methotrexate at ph-2.0. Absorption maxima 255.5nm Molar absorptivity (1 mole -1 /cm -1 ) 2.044*10 7 Best Fit Values Slope 0.0470±0.1153 Intercept 0.0518±0.2917 Slope when Y=0.0 0.05518 1/Slope 21.27 95% Confidence Interval Slope -0.0683 to 0.1623 Intercept -0.2399 to 0.3435 Goodness of Fit R 2 0.992 P value <0.001 Table 3.4: Statistical Data For Calibration Curve Of Methotrexate at ph-4.0. Absorption maxima 256.4 Molar absorptivity (1 mole -1 /cm -1 ) 3.04*10 7 Best Fit Values Slope 0.075415±0.0066703 Intercept -0.0597±0.09385 Slope when Y=0.0 0.06609 1/Slope 13.15 95% Confidence Interval Slope 0.06875 to 0.08208 Intercept -0.15355 to 0.03415 Goodness of Fit R 2 0.992 P value <0.001
ANALYTICAL PROFILE 90 3.2.2 Analytical method developed for Doxorubicin HCl Method: UV Spectroscopic method Equipments: Shimadzu UV 1601 spectrophotometer Procedure: Ten mg of drug was dissolved in 10 ml each of hydrochloric and acetate buffer (HCl buffer ph - 2.0 and acetate buffer ph - 4.0) further volume was made up to 100ml with buffer. From this solution 10ml was taken out and transferred into a 100ml volumetric flask, volume was make up to 100ml with respective buffer and from that pipetted out 10 ml in a test tube and subjected for UV-Vis scanning in the range 350-550nm. Preparation of calibration curve Method: Equipment: UV Spectroscopic method Shimadzu UV 1601 spectrophotometer Procedure: Accurately weighed 100mg of methotrexate was dissolved in different buffers (HCl buffer ph - 2.0, and acetate buffer ph - 4.0) in a 100ml volumetric flask, diluted with buffer to volume & mixed. If necessary agitate gently for rapid dissolution. Twenty ml of this solution was pipetted out into a second 100ml volumetric flask, buffer was added to make volume & mixed. A set of standard dilutions of 2, 4, 6, 8, and 10µg/ml of drug were prepared by transferring aliquots of 0.1, 0.2, 0.3, 0.4, and 0.5ml of stock solution (200µg/ml) in 10ml volumetric flask and volume make up to the mark with medium. The optical density values of resulting solutions were measured using 1cm cells at the wavelength of maximum absorbance using respective buffer as a blank and recorded in the table 3.5 and 3.6 with statistical data in table 3.7 and 3.8. The concentration versus absorbance values are plotted and given in figure 3.3 and 3.4 (119).
ANALYTICAL PROFILE 91 Table 3.5: Calibration Curve Data And Regression Values Of Doxorubicin HCl at ph 2.0. Concentration (µg/ml) Absorbance (nm) 2 0.06±0.29 4 0.10±0.26 6 0.14±0.12 8 0.18±0.22 10 0.22±0.17 n = 3, all values ± standard deviation 0.24 0.22 0.20 0.18 Absorbance (nm) 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0 2 4 6 8 10 12 Concentration (microgram/ml) Fig. 3.3 Standard Curve Of Doxorubicin HCl In Simulated Gastric Fluid at ph 2.0
ANALYTICAL PROFILE 92 Table 3.6: Calibration Curve Data And Regression Values Of Doxorubicin HCl at ph 4.0. Concentration (µg/ml) Absorbance (nm) 2 0.224±0.24 4 0.380±0.16 6 0.523±0.09 8 0.666±0.13 10 0.809±0.21 n = 3, all values ± standard deviation n = 3, all values ± standard deviation 0.9 0.8 0.7 Absorbance (nm) 0.6 0.5 0.4 0.3 0.2 0.1 0 2 4 6 8 10 12 Concentration (microgram/ml) Fig. 3.4 Standard Curve Of Doxorubicin HCl In Acetic Acid Buffer At ph 4.0
ANALYTICAL PROFILE 93 Table 3.7: Statistical Data For Calibration Curve Of Doxorubicin HCl at ph-2.0. Absorption maxima 496.6 Molar absorptivity (L mole -1 /cm -1 ) 1.5*10 7 Best Fit Values Slope 0.0204±0.0062798 Intercept 0.0174±0.0508001 Slope when Y=0.0 0.0214 1/Slope 49.01 95% Confidence Interval Slope 0.01412 to 0.02668 Intercept -0.0334 to 0.22448 Goodness of Fit R 2 0.997 P value <0.001 Table 3.8: Statistical Data For Calibration Curve Of Doxorubicin HCl At ph 4.0. Absorption maxima 495.8 Molar absorptivity (1 mole -1 /cm -1 ) 5.8*10 7 Best Fit Values Slope 0.0716±0.0084731 Intercept 0.0933±0.068403 Slope when Y=0.0 0.0842 1/Slope 13.96 95% Confidence Interval Slope 0.06312 to 0.0800731 Intercept 0.02489 to 0.161703 Goodness of Fit R 2 0.984 P value <0.001
ANALYTICAL PROFILE 94 3.2.3 Analytical Method Developed For 5-FU Method: UV Spectroscopic method Equipments: Shimadzu UV 1601 spectrophotometer Procedure: Ten mg of drug was dissolved in 10 ml of hydrochloric and acetate buffer (HCl buffer ph - 2.0 and acetate buffer ph - 4.0) further volume was made up to 100ml with buffer. From this solution pipette out 10ml and was transferred into a 100ml volumetric flask, volume was make upto 100ml with respective buffer and from that pipetted out 10 ml in a test tube and is subjected for UV-Vis scanning in the range 200-400nm was used. Preparation of calibration curve Method: UV Spectroscopic method Equipments: Shimadzu UV 1601 spectrophotometer Procedure: Accurately weighed 100mg of methotrexate was dissolved in different buffers (HCl buffer ph - 2.0 and acetate buffer ph - 4.0) in a 100ml volumetric flask, diluted with buffer to volume & mixed. If necessary agitate gently for rapid dissolution. Twenty ml of this solution was pipetted out into a second 100ml volumetric flask, buffer was added to make volume & mixed. A set of standard dilutions of 2, 4, 6, 8, and 10µg/ml of drug were prepared by transferring aliquots of 0.1, 0.2, 0.3, 0.4, and 0.5ml of stock solution (200µg/ml) in 10ml volumetric flask and volume make up to the mark with medium. The optical density values of resulting solutions were measured using 1cm cells at the wavelength of maximum absorbance using acetate buffer as a blank and recorded in the table 3.9 and 3.10 with statistical data in table 3.11 and 3.12. The concentration versus absorbance values are plotted and given in figure 3.5 and 3.6 (119).
ANALYTICAL PROFILE 95 Table 3.9 Calibration Curve Data And Regression Values Of 5-FU at ph 2.0. Concentration (µg/ml) Absorbance (nm) 2 0.077±0.26 4 0.183±0.18 6 0.294±0.14 8 0.406±0.25 10 0.518±0.28 n = 3, all values ± standard deviation 0.6 0.5 0.4 Absorbance (nm) 0.3 0.2 0.1 0.0 0 2 4 6 8 10 12 Concentration (microgram/ml) Fig. 3.5 Standard Curve Of 5-FU In Simulated Gastric Fluid at ph 2.0
ANALYTICAL PROFILE 96 Table 3.10 Calibration Curve Data And Regression Values Of 5-FU at ph 4.0. Concentration (µg/ml) Absorbance (nm) 2 0.140±0.09 4 0.260±0.18 6 0.380±0.12 8 0.500±0.23 10 0.620±0.28 n = 3, all values ± standard deviation 0.7 0.6 0.5 Absorbance (nm) 0.4 0.3 0.2 0.1 0 2 4 6 8 10 12 Concentration (microgram/ml) Fig. 3.6 Standard Curve Of 5-FU In Acetate Buffer at ph 4.0
ANALYTICAL PROFILE 97 Table 3.11: Statistical Data For Calibration Curve Of 5-FU at ph-2.0. Absorption maxima 265.6 Molar absorptivity (1 mole -1 /cm -1 ) 5.09*10 8 Best Fit Values Slope 0.05585±0.0080447 Intercept -0.0407±0.0649527 Slope when Y=0.0 0.0503 1/Slope 18.18 95% Confidence Interval Slope 0.0478053 to 0.063895 Intercept -0.105653 to 0.024253 Goodness of Fit r 2 0.987 P value <0.001 Table 3.12: Statistical Data For Calibration Curve Of 5-FU at ph-4.0. Absorption maxima 266.2 Molar absorptivity (1 mole -1 /cm -1 ) 8.0*10 6 Best Fit Values Slope 0.0467±0.0038945 Intercept 0.0168±0.0319583 Slope when Y=0.0 0.0489 1/Slope 21.41 95% Confidence Interval Slope 0.042805 to 0.050595 Intercept -0.01515 to 0.0487583 Goodness of Fit r 2 0.992 P value <0.001