الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This thesis deals with development of analytical methods for the determination of some selected drugs of different pharmacological categories acting as antimicrobial agents.
<The thesis comprises seven parts:
<Part I This part contains a general introduction about the chemical names, structures, physical properties, pharmacological actions and uses of the investigated drugs.
Detailed literature reviews
are presented showing the reported methods for analysis of the selected drugs in pharmaceutical
preparations, biological fluids and other possible matrices.
Part II: This part describes five simple and reliable spectrophotometric and chromatographic
methods for analysis of hepatitis C antiviral binary mixture of ledipasvir(LPV) and sofosbuvir
(SBV).
Method I is based on the use of Amax and derivative spectrophotometry with the zerocrossing
technique where LPV was determined using its Amax and 1D amplitudes at 324 and 338
nm respectively, while SBV was determined by measuring the 1D amplitudes at 276 nm.
Method II involves the application of the ratio spectra derivative spectrophotometry. For LPV, 12 μg/mL SBV was used as divisor and the 1DD amplitudes at 239.8 nm were plotted against LPV
concentrations; while by using 10 μg/mL LPV, the amplitudes at 279.2 nm were found
proportional to SBV concentrations.
Method III depends on ratio-difference measurement where the peak to trough amplitudes between 229.2 and 268.4 nm were measured and correlated to LPV
concentration. Similarly, the amplitudes between 268.6 and 229.2 nm in the SBV ratio spectra
were recorded.
For method IV, the two compounds were separated using HPTLC sheets of silica
gel and a mobile phase composed of chloroform-methanol (94:6) followed by densitometric
measurement of LPV and SBV spots at 331 and 267 nm respectively. Method V depends on
HPLC-DAD.
Effective chromatographic separation was achieved using Thermohypersil C8
column (4.6×250 mm, 5 μm) with a mobile phase consisting of 0.01 M sodium dihydrogen
phosphate (pH 2.5) and methanol (20:80) at a flow rate 1.2 mL/min and detection at 332 and 262
nm for LPV and SBV respectively. Analytical performance of the developed methods was
validated according to the ICH guidelines with respect to linearity, ranges, precision, accuracy,
detection and quantification limits.
The validated methods were successfully applied to the
simultaneous analysis of LPV and SBV in mixtures of different proportions and their combined
tablet dosage form.
Part III: This part presents a comprehensive stability indicating HPLC with diode array detection
method was developed for the determination of the recently approved antiviral drug daclatasvir
dihydrochloride (DCV) which is used for the treatment of chronic Hepatitis C Virus (HCV)
genotype 3 infection. Effective chromatographic separation was achieved using Waters C8
column (4.6 × 250 mm, 5 μm particle size) with isocratic elution of the mobile phase composed
of mixed phosphate buffer pH 2.5 and acetonitrile in the ratio of 75:25 (by volume).
The mobile phase was pumped at a flow rate of 1.2 mL/min, and quantification of DCV was based on
measuring its peak areas at 306 nm. DCV eluted at retention time 5.4 min.
Analytical
performance of the proposed HPLC procedure was thoroughly validated with respect to system
suitability, linearity, range, precision, accuracy, specificity, robustness, detection and
quantification limits.
The linearity range was 0.6 – 60 μg/mL with correlation coefficient 0.99999. The drug was subjected to forced degradation conditions of neutral, acidic and alkaline
hydrolysis, oxidation and thermal degradation.
< The proposed method proved to be stabilityindicating by resolution of the drug from its forced-degradation products.
The validated HPLC
method was successfully applied to analysis of the cited drug in its tablets.
Part IV: This part deals with the development & validation of a comprehensive stability-indicating
high performance liquid chromatography with diode array detection (HPLC-DAD) method for
simultaneous determination of sertaconazole nitrate (SN), sorbic acid (SA) and methylparaben
(MP).
To the best of our knowledge, no published methods could be found in the scientific literature for analysis of this ternary mixture.
Effective chromatographic separation was achieved
using Venusil XBP CN column (4.6 × 250 mm) with gradient elution of the mobile phase
composed of mixed phosphate buffer pH 2.5 and acetonitrile.
The quantification of SN was based
on measuring its peak areas at 225 nm, while the quantification of MP and SA was based on
measuring their peak areas at 259 nm. SA, MP and SN peaks eluted at retention times of 3.58,
4.26 and 11.28 min, respectively.
Analytical performance of the proposed HPLC procedure was
thoroughly validated with respect to system suitability, linearity, ranges, precision, accuracy, specificity, robustness, detection and quantification limits.
The linearity ranges for SN, MP and
SA were 1–200, 1–250 and 0.5–100 μg mL−1, respectively, with correlation coefficients 0.9999.
The analytes were subjected to forced-degradation conditions of neutral, acidic and
alkaline hydrolysis, oxidation, photo and thermal degradation.
The proposed method proved to be
analysis of TER, BHA & BHT in their combined suppository dosage form.
<The proposed method
made use of DAD as a tool for peak identity and purity confirmation.
Part VI: This part deals with the development and validation of a stability-indicating high
performance liquid chromatography with diode array detection (HPLC-DAD) method for
simultaneous determination of amprolium HCl (APH) & ethopabate (EPB).
To the best of our
knowledge, no stability-indicating method has been reported for analysis of this binary mixture.
Effective chromatographic separation was achieved using Kromasil CN column (4.6 × 250 mm)with gradient elution of the mobile phase composed of sodium hexane sulfonate and methanol.
The quantification of APH & EPB was based on measuring their peak areas at 266 nm. APH and
EPB peaks eluted at retention times of 10.42 and 18.53 min, respectively.
Analytical performance
of the proposed HPLC procedure was thoroughly validated with respect to system suitability,linearity, ranges, precision, accuracy, specificity, robustness, detection and quantification limits.
<The linearity ranges for APH and EPB were 1.5-240 and 1-160 μg/mL, respectively, with
correlation coefficients >0.9999.
The analytes were subjected to forced-degradation conditions of
neutral, acidic and alkaline hydrolysis, oxidation and thermal degradation. The proposed method
proved to be stability-indicating by resolution of the analytes from their forced-degradation
products.
Moreover, specificity of the method was verified by resolution of the analytes from
about 22 pharmaceutical compounds commonly used in antimicrobial veterinary products.
< The validated HPLC method was successfully applied to the analysis of the cited compounds in their
combined veterinary powder dosage form, in addition it was implemented in the accelerated
stability study of the dosage form when stored for 6 months at 40°C and 75% RH. The proposed
method made use of DAD as a tool for peak identity and purity confirmation.
<Part VII: This part describes three simple and direct spectrophotometric methods for determination of maduramicin Ammonium (MAD) through charge transfer complexation reactions.
This work is considered the first investigation for colorimetric methods for estimation of the drug.
The first
method is based on reaction of the drug with p-chloranilic acid (p-CA) in acetonitrile to give a
red colored product with maximum absorbance at 519 nm. The second method is based upon the
interaction of MAD and picric acid (PA) in chloroform resulting in the formation of a yellow
complex measured at 405 nm. The third method is based upon the interaction of MAD and 2,3-
dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in acetonitrile resulting in the formation of an
orange color measured at 588 nm.
Factors affecting the color development were studied and optimized.
The proposed colorimetric procedures were effectively validated with respect to linearity, ranges, precision, accuracy, robustness, detection and quantification limits.
analysis for the calibration curves of the formed color products with p-CA, PA and DDQ showed
good linear relationships over the concentration ranges of 100–1000, 30–150 and 25–250 μg/mL
respectively.
The methods were successfully applied to the assay of MAD in its pharmaceutical
preparation (premix for veterinary use) with good accuracy and precision.
The thesis consists of 271 pages and comprises 47 tables, 103 figures, 419 references and ends with an Arabic summary.