Development and Validation of Chiral Separation of Some Enantiomeric Drugs by HPLC and LC-MS

This thesis deals with the studies carried out by the writer in the laboratory for the past four years on the development and validation of chiral separation of some enantiomeric drugs by HPLC and LC-MS methods. Thesis begins with a brief introduction of the reasons for analysing enantiomeric drugs and introduction to the analytical methods used like HPLC and LC-MS. The methods used for the quantitative analysis of enantiomers and the introduction to the chiral separation are given. Thesis deals with the aim and objective of the present work, the reasons for analysing the enantiomers and need for newer analytical methods for the estimation of enantiomers in pharmaceutical formulation are briefly discussed. Thesis deals with the reviews of literature on the analytical methods available for the estimation of the drug candidates in pharmaceutical formulations are explained. Thesis deals with the materials and instruments used in the experimental procedures adopted. It describes in detail the procedure adopted for the optimisation of the chromatographic conditions for the chiral separation of drugs by HPLC and LC-MS methods and for the estimation of enantiomers in the selected drug candidates are presented and discussed. Forced degradation studies on the selected racemic drugs using acid, alkaline, neutral, oxidative and photolytic degradations and quantification of enantiomers by HPLC in different stress conditions are presented and discussed. The results obtained are presented and discussed. HPLC and LC-MS chromatograms of the standard and sample solutions, calibration curves for the selected analytes are also presented. The results of the experiments carried out to check the accuracy, reproducibility of the methods carried out are presented and discussed in detail. System suitability studies and forced degradation studies carried out for various methods developed are also presented and discussed. The following are some of the salient features and conclusions made for the present study. • Four racemic drugs namely Rosiglitazone, Pioglitazone, Zaltoprofen and Valganciclovir Hydrochloride for which there were no HPLC and LC-MS methods reported for the estimation of enantiomers in pharmaceutical formulations and their stability in different stress conditions were selected for the present study after thorough literature survey. • The chromatographic conditions like detection wavelength/mass range, nature and composition of mobile phase, nature of stationary phase, peak modifiers, flow rate etc were optimised for the best possible separation and quantification of the analytes. Forced degradation studies on the selected racemic drugs using acid, alkaline, neutral, oxidative and photolytic degradations were performed. • The developed HPLC and LC-MS methods were validated for their transferability to other laboratories, in terms of specificity, selectivity, accuracy, precision, linearity and range, detection and quantification limits, ruggedness, robustness and system suitability. The validation studies carried out revealed that the developed methods satisfy the ideal characteristics of the analytical methods. • The direct and indirect chiral HPLC and LC-MS methods developed in the present study for the estimation were found to be simple, rapid, accurate, precise, specific, linear and rugged. They are thus suitable for the estimation of enantiomers in raw materials and formulations. The newly developed analytical methods can be used in the following fields: • Research institutions, • Academic institutes, • Quality control department in industries, • Approved testing laboratories, • Biopharmaceutics and bioequivalence studies and • Clinical and pharmacokinetic studies after suitable modification

Route optimization via improved ant colony algorithm with graph network

Route optimization problem using vehicle routing problem (VRP) and time window constraint is explained as finding paths for a finite count of vehicles to provide service to a huge number of customers and hence, optimizing the path in a given duration of the time window. The vehicles in the loop have restricted intake of capacity. This path initiates from the depot, delivers the goods, and stops at the depot. Each customer is to serve exactly once. If the arrival of the vehicle is before the time window “opens” or when the time window “closes,” there will be waiting for cost and late cost. The challenge involved over here is to scheduling visits to customers who are only available during specific time windows. Ant colony optimization (ACO) algorithm is a meta-heuristic algorithm stimulated by the growing behaviour of real ants. In this paper, we combine the ACO algorithm with graph network henceforth increasing the number of vehicles in a particular depot for increasing the efficiency for timely delivery of the goods in a particular time width. This problem is solved by, an efficient technique known as the ACO+graph algorithm

A NEW VALIDATED CHIRAL RP-HPLC METHOD FOR THE DETERMINATION OF STABILITY OF MEBEVERINE ENANTIOMERS IN THE PRESENCE OF ITS DEGRADATION PRODUCTS

Objective: An enantioselective reverse phase high performance liquid chromatographic method was developed and validated for the analysis of mebeverine enantiomers. This method was used to investigate the stability and degradation behaviour of mebeverine under different stress conditions recommended by International Conference on Harmonization (ICH).Methods: An Isocratic chiral RP-HPLC method for the resolution of mebeverine and its degradation products was successfully achieved on a Phenomenex® lux cellulose 1 column, using UV detector at wavelength of 219 nm, with a mobile phase consisting of 0.1% diethyl amine in methanol, 20 mM ammonium bicarbonate (pH: 4.6) adjusted with trifluroacetic acid, 0.1% diethyl amine in isopropyl alcohol (55: 15: 30 v/v/v), and a flow rate of 1.2 ml/min. The drug was subjected to alkaline, acidic, neutral, oxidative, and photolytic conditions in order to mimic stress conditions. The stressed samples were also analysed by this method.Results: The method developed provided the linear correlation (R2 =0.999) for the drug between a range of 56–84 µg/ml for (-) mebeverine and 52–78 µg/ml (+) mebeverine respectively. The limit of detection and limit of quantification of (-) mebeverine was found to be 0.30 µg/ml, 0.90 µg/ml and (+) mebeverine was found to be 0.32 µg/ml, 0.97 µg/ml respectively.Conclusion: The method developed was found to provides good sensitivity and excellent precision and reproducibility and can be applied in the quality control of drug products.Â

STABILITY INDICATING CHIRAL HPLC METHOD FOR THE ESTIMATION OF PIOGLITAZONE ENANTIOMERS IN PHARMACEUTICAL FORMULATION

Objective: A stability indicating chiral high performance liquid chromatographic (HPLC) method was developed and validated for the separated (S)and (R) pioglitazone in raw material and its determination in the presence of degradation products formed during forced degradation studies.Methods: In the present study, an isocratic normal phase-HPLC method was developed with stationary phase as ACI Cellu 1 (150 mm × 4.6 mm i.d.,5  μ)  column  and  n-hexane:  N-propyl  alcohol  (80:20,  V/V)  as  mobile  phase.  The  entire  study  was  performed  using  1.0  ml/minute  as  flow  rate  and the detection wavelength at  233 nm. The pioglitazone (R and S) was exposed to various stress condition such as hydrolytic (acid and base), neutral, oxidative, and photolytic. The stressed samples were analyzed by the proposed method.Result:  The  described  method  was  linear  over  the  range  of  5-15 µg/ml  for  R-pioglitazone  and  4-14 µg/ml  for  S-pioglitazone.  The  limit  of  detection and limit of quantification of S-pioglitazone and R-pioglitazone were found to be 1.4 μg/ml and 4.26 μg/ml, respectively. The recovery study of S and R-Pioglitazone from tablets formulation ranged from 97.14% to 100.04%, respectively.Conclusion: The developed method can be applied in the quality control of drug products.Keywords: Stability-indicating method, Validation, Chiral, Pioglitazone

Microwave Irradated Synthesis, Characterization and Evaluation for their Antibacterial and Larvicidal Activities of some Novel Chalcone and Isoxazole Substituted 9-Anilino Acridines

Introduction: Chalcone, isoxazole and acridines have diverse biological activities. A series of novel chalcone and isoxazole substituted 9-anilinoacridines were synthesized for their antibacterial, larvicidal, activities.Methods: A series of novel chalcone and isoxazole substituted 9-anilinoacridines (3a-h and 4a-h) were synthesized from 9-chloroacridine by microwave irradiation method. The antibacterial evaluation was performed by cup-plate method and screened for their larvicidal activity by larval bioassay method. Result: The compounds 3d, 3e, 3f, 3h, 4d, 4f have significant antibacterial activity against Gram +ve bacteria like Staphylococcus aureus, Bacillus megaterium, and Gram –ve Escherichia coli, Klebsiella pneumoniae at 25μg/ml. Compounds 3c, 3f, 4a, 4f have significant larvicidal activity against culex and anopheles species at LC50value of 17-36ppm.Conclusion: Many of the compounds have significant antibacterial and larvicidal activities, which are used for further refinement.</p