الفهرس 
Introduction & Literature ReviewOnly 14 pages are availabe for public view
 |  | from | 346 |  |  |
| | | from | 346 | | |
Abstract
PART (I): Introduction and literature review
Introduction to Diabetes Mellitus was discussed with mentioning all categories of oral hypoglycemic drugs. Literature review was conducted for the studied drugs including alogliptin benzoate, pioglitazone hydrochloride, linagliptin and empagliflozin.
PART (II): chromatographic Methods PART II, SECTION (A):
Enhanced LC-MS/MS analysis of alogliptin benzoate and pioglitazone hydrochloride in human plasma, application to a pharmacokinetic study
A new fast LC-MS/MS method was developed for determination of alogliptin benzoate and pioglitazone hydrochloride in human plasma. Linearity ranges of 10-400 ng mL-1 for alogliptin benzoate and 25-2000 ng mL-1 for pioglitazone hydrochloride, were found to be suitable for their bioanalysis covering the Cmin and Cmax values of the drugs. Direct precipitation technique was used for simultaneous extraction of the drugs successfully from human plasma samples. The validated method was applied to a pharmacokinetic study on human volunteers. chromatographic separation was achieved on a BEH C18 column (50 mm
× 2.1 mm, 1.7 µm) with 0.1% aqueous formic acid: acetonitrile (40:60,
v/v) at a flow rate of 0.3 mL min-1. Monitoring the transition pairs of m/z
340.18 to 116.08 for alogliptin benzoate and m/z 356.99 to 133.92 for pioglitazone hydrochloride, using triple quadrupole mass spectrometer with multiple reaction monitoring, was achieved in the positive mode. The validated method is accurate and suitable for further clinical applications and possible bioequivalence studies.
PART II, SECTION (B):
LC-MS/MS analysis of linagliptin and empagliflozin in bulk and in pharmaceutical formulation
A new LC-MS/MS method was developed for determination of linagliptin and empagliflozin in pharmaceutical pure forms and dosage forms. Regression parameters, LOD, LOQ, accuracy and precision were investigated. Linearity was found to be acceptable over the concentration ranges of 25 - 800 ng mL-1 and 50 - 1600 ng mL-1 for linagliptin and empagliflozin, respectively. A mixture of 0.1 % aqueous formic acid and
acetonitrile in the ratio of (50:50, v/v) was used as a mobile phase at a flow rate of 0.2 mL min-1. The optimum values of cone voltage and collision energy were set at 20 V and 25 eV, respectively. Detection was performed using multiple-reaction monitoring (MRM) in the positive mode, by monitoring the transition pairs of m/z 473.01 to 420.10 and m/z
451.24 to 71.29 for linagliptin and empagliflozin, respectively. The optimized method was proved to be accurate for the quality control of the investigated drugs either in bulk or in pharmaceutical formulation.
PART II, SECTION (C):
Stability indicating HPLC assay of empagliflozin, application to degradation kinetics study
A stability-indicating HPLC method was developed for determination of empagliflozin. Empagliflozin was subjected to oxidation, wet heat, acid hydrolysis, alkali hydrolysis, and photo- degradation. Structure elucidation of the major degradation product was elucidated, using LC-MS and the alkaline degradation pathway was subjected to a kinetics study. Arrhenius plots were constructed and the activation energies of the degradation process were calculated. HPLC was used for the kinetic study as it enabled simultaneous determination of empagliflozin and the degradation product. Isocratic chromatographic elution was achieved for HPLC on Intersil® C18 column (150 mm × 4 mm, 5μm), using a mobile phase of potassium dihydrogen phosphate buffer pH (4) - acetonitrile (50:50, v/v) at a flow rate of 1 mL min-1 with UV detection at 225 nm. Linearity range was found to be 5-50 μg mL-1.
PART II, SECTION (D):
HPLC simultaneous determination of alogliptin benzoate- pioglitazone hydrochloride combination & linagliptin-empagliflozin combination
Two new, simple, selective and sensitive LC-UV methods have been developed and subsequently validated for simultaneous determination of alogliptin benzoate-pioglitazone hydrochloride combination & linagliptin - empagliflozin combination. Linearity was found to be acceptable over the concentration ranges of 0.5-25 μg mL-1 and 1-25 μg mL-1 for alogliptin benzoate and pioglitazone hydrochloride, respectively using the first method while the ranges were 2-50 μg mL-1 and 4-100 μg mL-1 for linagliptin and empagliflozin, respectively for the second method. Mobile phase consisting of 50 % methanol at pH 2.7 (adjusted with orthophosphoric acid) was used at a flow rate 0.8 mL min-1
with UV detection at 270 nm for the first method while 0.1% aqueous formic acid - methanol - acetonitrile (40:20:40, v/v/v), pH 3.6 was used as a mobile phase at a flow rate 2 mL min-1 with UV detection at 226 nm were applied for the second method. All the methods were applied successfully to the analysis of the pharmaceutical dosage forms. The optimized methods were validated and proved to be robust and accurate for the quality control of the mentioned drugs in their different pharmaceutical dosage forms.
PART (III): Spectroscopic Methods PART III, SECTION (A):
Stability indicating spectrofluorimetric assay of empagliflozin, application to content uniformity testing
A stability-indicating spectrofluorimetric method was developed for determination of empagliflozin. Empagliflozin was subjected to oxidation, wet heat, acid hydrolysis, alkali hydrolysis, and photo- degradation. The spectrofluorimetric assay was applied to content uniformity testing due to its higher sensitivity and lower LOD. The relative fluorescence intensity was recorded by spectrofluorimeter applying synchronous mode using ∆ λ = 70 at 297.6 nm. A marked decrease in spectra overlapping and marked increase in linearity parameters confirmed the advantages of using synchronous technique over the conventional spectrofluorimetric analysis. Linearity range was found to be 50-1000 ng mL-1.
PART III, SECTION (B):
Spectrophotometric methods for simultaneous determination of alogliptin benzoate-pioglitazone hydrochloride combination & linagliptin-empagliflozin combination
New methods were developed for alogliptin benzoate-pioglitazone hydrochloride combination with application on Oseni® tablets & linagliptin-empagliflozin combination with application on Glyxambi® tablets. Linearity ranges for the spectrophotometric approaches were found to be 5-15 μg mL-1 for alogliptin benzoate, pioglitazone hydrochloride and empagliflozin while it was 2-12 μg mL-1 for linagliptin. The proposed spectrophotometric methods included ratio subtraction coupled with extended ratio subtraction, spectrum subtraction coupled with constant multiplication and mean centering methods. Accepted LOD and LOQ values were obtained by all methods. Statistical analysis showed no significant difference between the developed methods
in comparison with the reference methods. The optimized methods provide fast and economic determination of the recently approved anti- diabetic combinations without complex instrumentation or time consuming mobile phase preparations that had been used in the chromatographic techniques reported in the literature.
PART IV: Chemometric Methods
Chemometric methods for simultaneous determination of alogliptin benzoate-pioglitazone hydrochloride combination & linagliptin- empagliflozin combination
New methods were developed for alogliptin benzoate-pioglitazone hydrochloride combination with application on Oseni® tablets & linagliptin-empagliflozin combination with application on Glyxambi® tablets. Linearity ranges for chemometric approaches using principal component regression (PCR) and partial least squares (PLS-2) were found to be 5-15 μg mL-1 and 5-25 μg mL-1 for alogliptin benzoate and pioglitazone hydrochloride, respectively while they were 2.5-12.5 μg mL-
1 and 2-10 μg mL-1 for linagliptin and empagliflozin, respectively. Accepted LOD and LOQ values were obtained by all methods. Statistical
analysis showed no significant difference between the developed methods in comparison with the reference methods. The optimized methods provide fast and economic determination of the recently approved anti- diabetic combinations without complex instrumentation or time consuming mobile phase preparations that had been used in the chromatographic techniques reported in the literature.
PART (V): General discussion
This part contains the general discussion of the whole thesis with the used references. Furthermore, the thesis contained 193 reference, 82 figures & 85 tables.