Tribute Dr Ghulam Mustafa Khan

Dr Ghulam Mustafa Khan [d. 2005] can truly be said to be a teacher of teachers [ustadh al-asatadha]. In his long and distinguished academic career spanning over six decades, he brought into existence literally hundreds of teachers in his subject Urdu and also created in many of them a taste for critical research that resulted in the existence of a whole corpus of standard critical material. This will endure in academic circles for a long time. It was his common habit to encourage his students, especially those of an academic bent of mind, to enrol for a Ph.D. In the course of which he would proffer them all kinds of assistance even if he were not their research supervisor. As such, the names of Dr Najmul Islam, who succeeded him as Chairman, Department of Urdu, University of Sindh, stands out. Dr Najmul Islam was the editor of a scholarly research journal, Tehqiq, which appeared in over 20 volumes in his own lifetime. Each issue contained scores of critical essays of a very high academic standard including his own [Dr N. Islam’s]. There is also the name of Dr Hasrat Kasganjvi, who emerged as a creative artist and critic of merit later on authoring dozens of books of high academic standard. The list is long and distinguished and contains the names of the major teachers of Urdu language and literature at the main Pakistani universities. Apart from Urdu teachers, the thousands of persons who had the benefit of attending his lectures and courses are also evidence of his intellectual wide-ranging scholarship. Then there is the select circle of his murids who formed his circle of spiritual knowledge and who had proffered their religious devotion at his hands. To these he gave the benefit of his spiritual counsel and advice as well as the vast knowledge he possessed of the Islamic sciences in his table-talk. Among these persons, the name of ex-President Ziaul Haq is most prominent.

Chromatographic Resolution of Closely Related Species in Pharmaceutical Chemistry: Drug Analogs and Isomers

A traditional approach to method development could flop to encounter desired separation downstream during test method validation, test method transfer or out of specification studies. In contrast, method development through quality by design (QbD) approach can result in a more rugged/robust method due to greater emphasis on risk management. A design of experiments (DOE) approach which involves both statistical analysis and modeling is used in a QbD approach to understand the impact and interactions between critical method variables. A QbD approach is applied in present study to drug analogs and isomers complex method development using Shimadzu LC Solution Software. The permissible nonconformities of method variables are determined within the design space – the proven acceptable ranges (PARs). The critical method variables in attaining chromatographic resolution for drug analogs and isomers were column chemistry, chromatography type, sample preparation and mobile phase. The prospective intrusion of method variables was determined in terms of desirable method responses, leading to a better method understanding besides achieving anticipated method quality. Effect of column physical properties (length and inner diameter) on separation and speed was investigated during initial screening experiments. Effect of chemical properties (type of surface, pore size and particle size of stationary phase) on sensitivity and retention factor were studied. Both pH and ionic strengths of the aqueous portion of mobile phase were considered in developing rugged methods that were not sensitive to small variations in conditions. Unified quantification methods for structural, functional and direct analogs of sartans (angiotensin II receptor antagonists), statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors), quinolones, proton pump inhibitors (PPI’s) with gastroprokinetic agents and dipeptidyl peptidase-4 (DPP-4) inhibitors with biguanide are developed. Additionally enantiomers of linagliptin, sitagliptin phosphate, cetirizine hydrochloride, solifenacin succinate and montelukast sodium are separated on Diacel Chiralpak IC stationary phase instead of using separate stationary phase for individual enantiomeric separation. The proposed methods were statistically validated in terms of precision, accuracy, linearity, specificity, selectivity and robustness in accordance with guidelines of International Council on Harmonisation (ICH). The newly developed methods proved to be specific, accurate and robust for the unified quantification of drug analogs in commercial pharmaceutical formulations and to confirm the relative abundance of desired enantiomer in a racemic mixture of active pharmaceutical ingredient. The advantage of developed methods for unified quantification of drug analogs is that only one sample is prepared and single chromatographic run is required to provide information on the identity, content uniformity, dissolution, potency and purity of active pharmaceutical ingredients. Therefore, these methods can be handy in daily sample handling in routine, when many samples of drug analogs are analyzed in drug testing laboratories. The proposed methods are able to discriminate not only between different drug analogs and enantiomers but are also able to detect counterfeit products.