Home > Synthesis and Pharmacological Profiling of Gabapentin and Pregabalin Derivatives As Potential Therapeutic Agents in the Treatment of Neuropathic Pain
Synthesis and Pharmacological Profiling of Gabapentin and Pregabalin Derivatives As Potential Therapeutic Agents in the Treatment of Neuropathic Pain
The present work describes the synthesis and pharmacological evaluation of gabapentin (GBP) and pregabalin (PGB) derivatives as potential therapeutic agents for the treatment of neuropathic pain. Synthesis of novel molecules for the treatment of different disease conditions has long been a strategy of the synthetic chemists. Organic synthesis utilizes the fundamental approach for the development of active molecules utilizing the hypothesis that the active molecules bind to an active site of enzymes or proteins with the subsequent response in the shape of a distinct biological activity. Chemically modifying the active molecule might result in an increase, decline or modification of the biological activity. From this basic thought, a panoptic range of dissimilar structures can be derived, extending to the development of superior and more efficient therapeutic agents. The hypothesis of modifying the structures of the PGB and GBP in an attempt to obtain newer molecules for the treatment of neuropathic pain with higher therapeutic potential, safety, and lesser side effects (as associated with the currently available treatments of neuropathic pain), persuaded us to chemically change their structures by incorporating salicylaldehyde moiety at their amine functionality. Neuropathic pain, the pain that originates from neuronal damage, is a chronic and enfeebling condition that imparts a lot of distress to the patients suffering from it. A number of studies have revealed a potential effectiveness of opioids, tricyclic antidepressants (TCAs), mexilitine, tramadol, and anticonvulsants like PGB, GBP, phenytoin, and lamotrigine for painful neuropathic conditions. Nevertheless, all these therapies only have an effectiveness rate of 30-50 percent in reducing pain and are treatment with these agents is stopped due to serious side effects, sedation being the most common.PGB and GBP are amino acids with anticonvulsant, analgesic and anxiolytic like activities. PGB was intended as a lipophilic analogue of GABA and was substituted at 3 position in order to assist its passage across the blood brain barrier (BBB). On the other hand, GBP was developed initially for the treatment of partial seizures (as add on therapy) but it was found to have effects in the treatment of post herpetic neuralgia (PHN) in various neuropathic preclinical pain models. The gabapentinoid anticonvulsants, PGB and GBP, have established efficacy in both preclinical and clinical neuropathic and chronic cancer pain research. PGB and GBP, though are the GABA analogues, but have a distinct mechanism of action than that of GABA. They act on the α2δ1 subunit of voltage gated calcium channels whereas GABA acts either on GABAA, GABAB or GABAC receptors. GBP has been utilized for the treatment of a range of neuropathic pain, anxiety, inflammation and in a number of other conditions. Similarly, the effectiveness of PGB in these conditions is well documented. After synthesis of PGB and GBP derivatives and their chemical characterization utilizing various analytical tools like 1H NMR, 13C NMR, IR, UV, and MS, these derivative were evaluated by employing various pharmacological assays. Following the synthesis and characterization of these compounds (PGS and GPS), acute toxicity study was undertaken to institute the safety windows. In the third phase, after synthesis and toxicological study, these derivatives were then tested inthe preliminary paradigms of nociception (hot plate and abdominal stretch tests in mice), inflammation (carrageenan, histamine, and serotonin induced paw edema models in mice) , and pyrexia (Brewer''s yeast induced pyrexia model in mice) where they showed significant antinociceptive, anti-inflammatory, and antipyretic proclivities. The antinociceptive effects of PGS and GPS in abdominal stretch test were ostensibly antagonized naloxone, while the antinociceptive effects of these compounds in the hot plate test were preferentially antagonized by naloxone (1 mg/kg, s.c) and pentylenetetrazole (PTZ) (15 mg/kg, i.p). The promising results from antinociceptive, anti-inflammatory, and antipyretic assays intrigued us to evaluate these compounds for their antiallodynic and antihyperalgesic potential in various neuropathic pain models including diabetes-induced (disease induced), chemotherapy-induced (treatment-induced) and chronic constriction injury induced (surgically-induced) neuropathic pain using either von Frey filament or cotton bud stimuli. In case of diabetes induced neuropathy model, antivulvodynic effects of these compounds were also evaluated. Here, hyperglycemia was induced via single injection of streptozotocin (45 mg/kg). PGS (30, 50, 75, and 100 mg/kg) and GPS (25, 50, 75 and 100 mg/kg) showed static/dynamic anti-allodynic [(increased paw withdrawal threshold (PWT) and latency (PWL)] in addition to static/dynamic anti-vulvodynia effects [increased flinching response threshold (FRT) and latency (FRL)], when compared to the positive controls, PGB (30 mg/kg) and GBP (100 mg/kg), and the vehicle control groups. The encouraging results from the STZ induced diabetic neuropathic pain model further enchanted us to evaluate these compounds in a chemotherapy induced peripheral neuropathy model (CIPN) in rats and also in chronic constriction injury (CCI) model of neuropathic pain. In CIPN model, both PGS (30, 50, 75, and 100 mg/kg) and GPS (25, 50, 75, and 100 mg/kg), demonstrated a significant effect in the amelioration of cisplatin (3.0 mg/kg, i.p) induced thermohypoalgesia and allodynia. Thermohypoalgesia attenuating potential of these compound imply an involvement of TRP channels which are specifically associated with thermo-perception. On the other hand, the promising results from the CCI model revealed that PGS and GPS possess significant ameliorating effects on suppressing of the neuropathic pain symptoms like mechanical allodynia, mechanical hyperalgesia, thermal hyperalgesia, and cold allodynia. Chronic pain and anxiety have a deep connection and keeping this in view, anxiolytic activity of PGS and GPS was evaluated in open-field, staircase, and elevated plus-maze tests. Bothe PGS and GPS produced anxiolytic-like effects at the tested doses that were evident in the open-field epitome from an increased time spent in the centre and no effect on the locomotor activity at all the tested doses, except for 100 mg/kg GPS dose where a mild decrease in locomotion was observed. PGS and GPS decreased the rearing incidence without suppressing the NSA in the staircase test. They also increased the number of entries to and time spent on open arms / central platform, respectively, as well as the frequency of head-dipping in the mouse elevated plus-maze assay. PTZ (15 mg/kg), a non-selective GABA antagonist, preferentially antagonized all these effects produced by PGS and GPS. In conclusion, PGS and GPS revealed promising anti-nociceptive, anti-inflammatory, anti-febrile, anti-allodynia (and anti-vulvodynia), anti-hyperalgesia, anti thermohypoalgesia, and anxiolytic propensities with a wider safety margins.
جب چئیر مین ذوالفقار علی بھٹو کے پروانے جل اٹھے تھے۔ ہے کوئی جو اپنے لیڈر کے لیے خود پر تیل چھڑک کر آ گ لگا لے ۔تقریباََ سات کارکنوں نے اپنی جانیں ذوالفقار علی بھٹو شہید پر قربان کیں چئیر مینذوالفقار علی بھٹو نے سپریم کورٹ میں کھڑے ہو کر کہ کوئی کسی کے لیے اپنی انگلی کو نہیں جلا سکتا میرے جان نثاروں نے اپنی جانیں قربان کر دیں ۔
جب پروانے جل اٹھے تھے۔ یہ قبریں پنجاب اور ایک تصویر آزاد کشمیر کے ان پروانوں کی ہیں جو اپنے قائد کو پھا نسی چڑھتا ہوا نہیں دیکھ سکتے تھے اور خود پر تیل چھڑک کر خود سوزی کر کے اپنے قائد چئیر مین ذوالفقار علی بھٹو شہید پر قربان ہو گئے ۔پہلی قبر گوجرانوالہ کے وحید قریشی کی دوسری تیسری فیصل آ باد کے رشید عاجز اور یعقوب پرویز کھوکھر ،چوتھی تصویر آزاد کشمیر کے خود سوزی کر نے والے عزیز ملک کی ہے ۔
Despite his being a staunch Mutazali, Allama Zamakhshari declares the Holy Quran to be a miracle on account of its unique coherence and cohesion. For the first time in the history of Quranic exegesis, he made a subject of the mutual juxtaposition of Quranic words, sentences, verses and surahs such discussions on the Quranic cohesion as are related to literary and communicative aspects such as metaphor, simile, allusion and syntax. Similarly, he demonstrated the Quranic cohesiveness by beautifully applying the roles and regulations of rhetoric on the verses of the Holy Quran. Such forms of coherence and cohesion did he adopt as can be declared as the fundamentals of the idea of the Quranic cohesion. In this regard, this article is the first such comprehensive study of the Tafseer e Kashaf.
Title: Relationship among Qualifications, Experience, Gender, Professional Attitudes, and Performance of Directors of Physical Education in Administration of Sports Activities in Government Colleges Pages: 224 Researcher: Salahuddin Khan Advisor: Professor Dr. Muhammad Shah University: Gomal University Dera Ismail Khan (Pakistan) Year: 2008 Subject Area: Sports Sciences Degree: PhD in Education The purpose of the study was to investigate the relationship of experience, qualifications, and gender with professional attitudes and performance of Directors of Physical Education working in government colleges of North West Frontier Province (NWFP) Pakistan. Seven Research questions were formulated in order to find out; (a) is there any relationship of professional attitudes with experience, qualifications, and gender of Directors of Physical Education, (b) Is there any relationship of ivPerformance with experience, qualifications, and gender of Directors of Physical Education?(c) is there any relationship of performance (General Qualities) aspects of DPEs with their experience, qualifications, and gender, (d) is there any relationship of performance (Content Knowledge) aspects of DPEs with their experience, qualifications, and gender, (e) is there any relationship of performance (Classroom Management) aspects of DPEs with their experience, qualifications, and gender, (f) is there any relationship of performance (Coaching Performance) aspects of DPEs with their experience, qualifications, and gender, and (g) is there any relationship of performance (Professional and Personal Qualities) aspects of DPEs with their experience, qualifications, and gender. For data collection two types of instruments were used (a) professional attitudes having 57 items and (b) DPEs performance evaluation having 64 items. These instruments were developed from the available literature (Baumgartner et al (1995), Corbin B. Charles et al (2004), Bucher A. Charles (1978), Mathews K. Donald (1978), Best W. John (1977), Safrit J. Margaret (1981), Johnson L. Barry et al (1988) and Shah M (2004), and (Evaluation of Student Teaching Final Report form of Towson University Maryland), and from different instruments already used for attitude measures and performance evaluation. In order to make the instrument reliable, both the instruments were send to 70 experts all over the country (mostly from NWFP the province where vthe study was conducted, from Sindh province, Punjab province and from Islamabad the Capital of Pakistan), out of which 50 responses were received. The responses were analyzed for reliability in statistical program “STATISTICA”. For professional attitudes instrument out of 57 items, 39 items were selected as reliable having the Cronbach alpha 0.90. Similarly for performance evaluation of DPEs instrument out of 64 items, only 41 items were selected as reliable having the Cronbach alpha 0.94. The professional attitudes scale having 39 reliable items was administered among 90 Directors of Physical Education working in 72 different colleges in NWFP, while performance evaluation scale having 41 reliable items was administered among 1800 students of graduate level studying in the colleges of NWFP. Responses were quantified with 1= strongly disagree, 2= disagree, 3= neutral, 4= agree, and 5= strongly agree. In professional attitudes scale the scores were revised in case of items showing negative attitudes. In order to analyze the data Pearson Product Moment of co-efficient of correlation “r” was used as statistical technique. Main findings of the study were as follows: (a) the professional attitudes of Directors of Physical Education relationship with experience, qualifications, and gender were not significant. (b) The performance of Directors of Physical Education relationship with experience was found insignificant. Similarly, qualifications and gender were also found insignificant when correlated with the performance of Directors of Physical viEducation. (c) The relationship of performance (General Qualities) aspects with experience, qualifications, and gender of Directors of Physical Education were not significant. (d) The performance (Content Knowledge and teaching skills) aspects were found insignificant when correlated with experience, and gender of Directors of Physical Education, while (Content Knowledge & teaching skills) aspects of performance of Directors of Physical Education were positively correlated with qualifications. (e) The performance (Classroom Management) aspects were positively correlated with experience and qualifications; on the other hand it was negatively correlated with gender of Directors of Physical Education. (f) Coaching aspect of performance was not significantly correlated with experience, and qualifications of Directors of Physical Education. On the other hand (Coaching Performance) aspects were negatively correlated with gender (Female) of Directors of Physical Education. (g) No significant relationships were found between performance (Professional and Personal Qualities) aspects of Directors of Physical Education with their experience, qualifications, and gender.