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Home > Determination of Impurities in Drug Substances

Determination of Impurities in Drug Substances

Thesis Info

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Author

Saquib, Najam-Us-

Program

PhD

Institute

Hamdard University

City

Karachi

Province

Sindh

Country

Pakistan

Thesis Completing Year

2010

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1401

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725843957

Similar


The present investigation involves a study of the characterization and determination of the major degradation impurities in selected drug substances and formulated products, i.e. bromazepam, diazepam, Cefixime trihydarte, cefazolin sodioum, simvastatin and lovastatin.. High Performance Liquid Chromatographic (HPLC) method has been used for the characterization of impurities present in a certain drug substance on comparison with the retention times of the reference standards. A complete separation of the individual drug substances and their major impurities has been achieved before a consideration of their determination. The tR values of the parent compounds are in the range of 2.71-9.22 and those of the impurities in the range of 1.23-20.57 min. Thus the separation and determination of these compounds can be carried out within 20 minutes. The HPLC assay method has been used to determine the parent compounds and their impurities after validation of the European Pharmacopoeal method used in this study. The validation of the HPLC method for the parent drugs and their degradation impurities involved the study of the parameters like specificity, linearity, precision and accuracy. In order to apply this method to the individual drug substances and their impurities all these parameters have been studied for each compound and the relevant data are presented. The overall recoveries of the parent drug substances and their impurities are in the range of 98 – 102%. The reproducibility of the method lies within 3% under the conditions used in this study. It needs to be emphasized that under pharmacopoeal requirements and guidelines of regulatory agencies it is mandatory to determine the impurities in excess of 0.1 % for the safety, efficacy and quality of the drugs. It is also important with a view point of the effect of variations in the synthetic routes of different manufacturers as well as due to the effects of packaging, shipment, and storage conditions. In addition to this the formulation adjuvants may also play a role in the formation of degradation impurities. The % contents of the selected drugs and their major degradation impurities in raw materials and formulated products have been determined and the range of the level of these impurities has been stated. In all cases the % content of the parent drugs and the formulated products are within the prescribed limits. However, the degradation impurities in the raw material as well as in the formulated product appear to exceed the level prescribed by ICH and other regulatory agencies. This could possibly result from variations in the manufacturing synthetic processes of different manufacturers for the raw materials and the manufacturing procedures and drug-excipient interactions for the formulated products. An attempt has been made to conduct forced degradation studies on these drug substances to predict the formation of different degradation products under stress conditions. This study includes the acid and alkaline hydrolysis and oxidation using H2O2. In acid solution the degradation appears to be higher than that observed in the alkaline medium (80 ± 0C). The major route of degradation of these compounds is hydrolytic cleavage of the molecule which may result from the effects of drug- excipient interactions and the environmental factors. The present study provides useful information to the formulator in the design of formulation strategies to minimize the formation of degradation impurities so as to achieve a better quality and efficacy of the formulated products. It also establishes the importance of the effects of variations in synthetic routes, process parameter and role of excipients on the formation of impurities.
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آئی کیڈی اے پھلاں سی بہار ایدکیں

آئی کیڈی اے پھلاں دی بہار ایدکیں

دے جاویں جے آکے دیدار ایدکیں
پڑی تے شفا والی دینی پونی ایں

بوہے ترے ڈگے نیں بیمار ایدکیں
ساری میں حیاتی تینوں سینے تے کھیڈایا اے

چائے نہیں جاندے میتھوں بھار ایدکیں
دکھاں دی اوہ پنڈ پوندھی چائی واندے نیں

اینویں نہ بے دوسیاں نوں مار ایدکیں
دنیا نوں رج تے ہنیر آگیا اے

بہل نہیں چوندے پئے کبھار ایدکیں
رکشیاں سکوٹراں نے جان کڈھ لئی

گھوڑے تے نہیں دِسدے سوار ایدکیں
سد کے عاشقاں نوں ، بیٹھکے بہایا کر

راہواں وچہ اینویں نہ کھلار ایدکیں
چاہن والے تینوں ہُن سارے چھڈ گئے نیں

رہ گئے نے ویکھ لے دو چار ایدکیں
ساقی بڑا نشہ توں صراحی وچ پایا اے

مست ہوئے پھردے میخوار ایدکیں
میزائلاں اتے ایٹماں دی جنگ ہُن لگسی

اونی نہیں کم تلوار ایدکیں
چڑھدی جوانی تک شمع والی عاشقاں

ہوئے نے پتنگے کئی نثار ایدکیں
اگے وی گلاباں نال مکھڑا سجاویں توں

سُرمے دی وکھری اے دھار ایدکیں
سب کرتوت ہُن سامنے پئے اوندے نے

قوم نے ہو جانا ایں بیدار ایدکیں

ہک دھی رانی دی فریاد
بولے جدوں بنیرے کاں

میں سمجھ جاندی ہاں
گل ہے ضرور اولی

تاہیوں کردا اے کاں کاں
کائی دس پیغام خوشی دا

مینوں درداں ماریا تھاں
میں کٹھی وچ ہجر دے

میری نکلی جاندی جاں
میرے سینے پھٹ انوکھا

کر سکدی نہیں عیاں
میری سن فریاد اے امبڑی

جے توں ہیں میری ماں
نہیں سُجھدے ریشم گوٹے

The Extent to Which Pupils Have Adopted the Values of Middle School English Book Year Three

The present study aims at determining the extent to which the values, derived from the second-generation curriculum and introduced in the third-year middle school English book, are adopted by teenagers to help them overcome their identity crisis, in Algeria. To achieve this aim, two questionnaires applied to 70 third year teenage pupils were carried out. One prior to the study with the third year English book, the other one after the study.The results of the two questionnaires were compared and showed that the values total average has increased from 16.06 in the first questionnaire to 21.33 in the second. An increase has also been noticed in the averages of the four value dimensions: national identity (from 4.76 to 6.10), national awareness (from 3.63 to 5.36), citizenship (from 4.13 to 5.31) and openness to the world (from 3.50 to 4.50). The previous results confirm that there is an improvement in the values of pupils yet the commitment to the values of « openness to the world » dimension is still weak compared to the other ones and needs further research to be improved.

Computational and Molecular Analysis of Tp53, Pten and Ar Genes in Prostate Adenocarcinoma

Prostate adenocarcinoma (PCa) is one among the most common global disorders affecting men and is a leading cause of cancer related mortality. In the present study, TP53, PTEN and AR genes in 680 histologically confirmed prostate cancer patients and 500 controls from Pakistan were investigated to unravel their role in prostate cancer. Exon specific primers were designed for all the exons of the three genes along with flanking intronic and UTR regions. Sequence changes were initially screened by PCR-SSCP and then confirmed through automated sequencing. Our data showed that none of the samples had a complete deletion of any of the three genes. A total of twenty six novel exonic mutations and eight novel intronic variants were detected in the target genes along with the four previously reported exonic alterations. The intronic variants were observed both in cases and controls and thus were further investigated for their possible association with the disease through un-conditional logistic regression under different genetic models. The g.7675016T>A variant of TP53 showed significant association with increased PCa risk under allelic contrast (OR=1.84, 95%CI=1.29-2.63, p-value=0.001), heterozygous model (OR=2.25, 95%CI=1.37-3.69, p-value=0.001) and dominant model (OR=2.13, 95%CI=1.38-3.28, p-value=0.001) while its g.7674991T>A variant showed positive association in all genetic models except TT vs TC and recessive model. In our studied population, we observed non-significant association for g.87891382G>A variant of PTEN in all models except allelic contrast (OR=1.87, 95%CI=1.36-2.58, p-value=0.000), while the other three variants of PTEN showed positive correlation with increased PCa risk. Similarly, both the intronic variants of AR gene were also found associated with increased PCa risk. The AA genotypes of g.67637091T>A variant and CC of g.67724021T>C variant are more common in cases. Homozygous individuals for A allele has 3.68 times higher risk of prostate cancer. Majority of the mutations are novel and thus establishing their pathogenicity is of prime diagnostic importance. A comprehensive structural and functional annotation was therefore reported in the present study for the observed mutations through the application of bioinformatics approaches. It was noticed that 5/8 of TP53 mutations (P152A, T170M, E171R, H179Q and V203G), 7/9 of PTEN mutations (A86P, E91K, H93Q, Q97H, E99X, H272F and E288F), while 11/13 of the AR gene mutations (I870fs, I870_splice, D880Y, E884X, I900V, S909C, K906N, L908P, V912G, I915F and Y916S) were predicted to endorse changes in their respective protein structure and thus are functionally damaging. Phenotypic data was collected in integration with the genotypic data from all the study participants and was statistically evaluated for their correlation and impact on individual’s survival. Age, smoking CVDs, BMI, dairy products consumption, physical activity, family history and hypertension was observed responsible for increasing prostate cancer risk under uni-variate and multi-variate models. The diabetic patients were observed at lower risk of having PCa while others risk factors were found non-associated. Overall survival analysis showed a median survival time of 21 months for the PCa patients (95%CI= 18-26). Intra-group differences in patient’s survival after adjusting for confounder age were confirmed through a proportional hazard model. It was observed that age, BMI, smoking, prostectomy and physical activities are associated with survival probability while the rest of risk factors have no effect on survival. It was further noticed that diabetic patients has better survival length as compared to the non-diabetic counterparts. Our results elucidate the significance of combining molecular and in silico approaches to fully distinguish pathogenic mutations from benign which will have profound effects on the patient management. We also have developed an integrated platform, pakprostate.com during the course of study to provide users the facility to search literature, genes, drugs, to have access to download verified dataset, can upload data, can apply basic stats and visualize data just on click of a button. The repository pakprostate is freely available online at the URL www.pakprostate.com. Case-control samples were collected from all the four provinces of Pakistan including Capital territory, Gilgit-baltistan and Kashmir. It is thus hoped that, this study is a good representation of Pakistani population.