Fazli Khuda

Anti-inflammatory activities of Sieboldogenin from Smilax china Linn.: Experimental and computational studies

ETHNOPHARMACOLOGICAL RELEVANCE Smilax china Linn. is extensively used in traditional Chinese medicine (TCM) as well as in Pakistan for several medicinal purposes including their use in inflammatory disorders. AIM OF THE STUDY The aims of the current study were to validate and assess the folk use of Smilax china Linn. on pharmacological grounds using the isolated compound at molecular, in vivo and computational levels. MATERIALS AND METHODS Seiboldogenin was isolated from ethyl acetate fraction of the plant crude extract. In vitro lipoxygenase and in vivo carrageenan-induced hind paw oedema models were used in experimental studies while molecular docking technique was used to conduct computational study. RESULTS Sieboldogenin showed significant lipoxygenase inhibition (IC50: 38 microM). It also exhibited significant inhibition (p<0.05) of carrageenan-induced hind paw oedema at the doses of 10 and 50mg/kg. Computational molecular docking showed its molecular interaction with important amino acid residues in the catalytic site of lipoxygenase, revealing its potential binding mode at molecular level. CONCLUSIONS Sieboldogenin seems to be a potential new anti-inflammatory compound responsible for anti-inflammatory activities of Smilax china Linn. Its in vitro and in vivo inflammatory activities are in good agreement with the folk medicinal use of Smilax china Linn. in inflammatory disorders.

Assessment of potential toxicity of a smokeless tobacco product (naswar) available on the Pakistani market

Background ‘Naswar’ is a smokeless tobacco product (STP) widely used in Pakistan. It has been correlated with oral and oesophageal cancer in recent clinical studies. The toxic effects associated with STPs have been associated with trace level contaminants present in these products. The toxin levels of Pakistani naswar are reported for the first time in this study. Methods A total of 30 Pakistani brands of naswar were tested for a variety of toxic constituents and carcinogens such as cadmium, arsenic, lead and other carcinogenic metals, nitrite and nitrate, and nicotine and pH. Results The average values of all the toxins studied were well above their allowable limits, making the product a health risk for consumers. Calculated lifetime cancer risk from cadmium and lead was 1 lac (100000) to 10 lac (1000000) times higher than the minimum 10E_4 (0.00001) to 10E_6 (0.000001), which is the ‘target range’ for potentially hazardous substances, according to the US Environmental Protection Agency. Similarly, the level of arsenic was in the range of 0.15 to 14.04 μg/g, the average being 1.25 μg/g. The estimated average bioavailable concentration of arsenic is 0.125–0.25 μg/g, which is higher than the allowable standard of 0.01 μg/g. Similarly, the average minimum daily intake of chromium and nickel was 126.97 μg and 122.01 μg, as compared to allowable 30–35 μg and 35 μg, respectively; a 4–5 times higher exposure. However, beryllium was not detected in any of the brands studied. The pH was highly basic, averaging 8.56, which favours the formation of tobacco specific amines thus making the product potentially toxic. This study validates clinical studies correlating incidence of cancer with naswar use in Pakistan. Conclusions This study shows that the production, packaging, sale and consumption of naswar should be regulated so as to protect the public from the health hazards associated with its consumption.

Development and evaluation of diclofenac sodium thermorevesible subcutaneous drug delivery system

The objective of current work was to develop and evaluate thermoreversible subcutaneous drug delivery system for diclofenac sodium. The poloxamer 407, methyl cellulose, hydroxypropyl methyl cellulose and polyethylene glycol were used alone and in combination in different ratios to design the delivery system. The physical properties like Tsol-gel, viscosity, clarity of solution and gel were evaluated. The in vitro release of the drug delivery system was evaluated using membrane less method and the drug release kinetics and mechanism was predicted by applying various mathematical models to the in vitro dissolution data. Rabbits were used as in vivo model following subcutaneous injection to predict various pharmacokinetics parameters by applying Pk-Summit software. The in vitro and in vivo data revealed that the system consisting of the poloxamer 407 in concentration of 20% (DP20) was the most capable formulation for extending the drug release and maintaining therapeutic blood level of DS for longer duration (144 h). The data obtained for drug content after autoclaving the solutions indicate that autoclaving results in 6% degradation of DS. The data also suggested that the studied polymers poloxamer, MC and PG are good candidate to extend the drug release possessing a unique thermoreversible property.

Development and evaluation of pluronic- and methylcellulose-based thermoreversible drug delivery system for insulin

Abstract The objective of the current work was to develop and evaluate thermoreversible subcutaneous drug delivery system for Insulin. Thermoreversible in-situ gel system was developed and evaluated both in-vitro and in-vivo comprising of pluronic F-127 alone or in combination with methylcellulose in different ratios. The drug release kinetics and mechanism was predicted by applying various mathematical models to the in-vitro dissolution data. Rabbits were used as animal model following subcutaneous injection to predict various pharmacokinetic parameters by applying Pk-Summit® software. The in-vitro and in-vivo data revealed that the formulation IPM 15/3 consisting of the pluronic F-127 (15% w/v) and methylcellulose (3% w/v) was the most robust and capable formulation for extending the drug release and maintaining basal plasma insulin level between 10 and 40 µU/ml for 240 h (10 d).

Method development and validation for simultaneous determination of lumefantrine and its major metabolite, desbutyl lumefantrine in human plasma using RP-HPLC/UV detection

A simple, specific, precise and rapid RP-HPLC-UV method was developed for simultaneous determination of lumefantrine and its metabolite desbutyl lumefantrine in human plasma. Experimental parameters were optimized and the method was validated according to standard guidelines. The method showed adequate separation for lumefantrine and desbutyl lumefantrine and best resolution was achieved with Supelco Discovery HS C18 RP (150mm×4.6mm, 5μm) column using acetonitrile and 0.05% trifluroacetic acid (70:30, v/v) as a mobile phase pumped at a flow rate of 1.0ml/min and wavelength of 335nm. The method was linear over the concentration range of 10-12,000ng/ml. The lower limit of detection (LLOD) and lower limit of quantification (LLOQ) for lumefantrine were 10.0 and 18.0ng/ml, while for desbutyl lumefantrine were 7.5 and 15.0ng/ml, respectively. The proposed method was efficiently applied for determination of lumefantrine and desbutyl lumefantrine concentrations in plasma samples for pharmacokinetic studies.

Determination of Rosuvastatin and its Metabolite N-Desmethyl Rosuvastatin in Human Plasma by Liquid Chromatography–High Resolution Mass Spectrometry: Method Development, Validation, and Application to Pharmacokinetic Study

A novel liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed for the determination of rosuvastatin (rosuva) and its metabolite N-desmethyl rosuvastatin (NDM-rosuva) in human plasma using atorvastatin as internal standard. The method was validated according to international guidelines. The analytical column used was HiChrom® C18 (150 × 3.0 mm, 3 µm; Reading, UK) and the mobile phase comprised of 0.1% formic acid in acetonitrile and 0.1% formic acid in water (70:30 v/v), pumped at 300 µL/min. The precipitation of plasma proteins and extraction of analytes were carried out by a simple one-step procedure using acetonitrile. The calibration curves were linear (r2 = 0.999) over the concentration range of 0.2–20 ng/mL for rosuva and 0.1–10 ng/mL for NDM-rosuva. The lower limits of detection and quantification for rosuva were 0.1 and 0.2 ng/mL, whereas for NDM-rosuva, these were 0.03 and 0.1 ng/mL, respectively. The intra- and inter-day precisions expressed as relative standard deviations (RSDs) were less than 2.5%. The average absolute recoveries of both rosuva and NDM-rosuva were greater than 95%. The method was successfully applied for the determination of rosuva and NDM-rosuva pharmacokinetics and drug–drug interaction studies.

Genetic Susceptibility to Oral Cancer due to Combined Effects of GSTT1, GSTM1 and CYP1A1 Gene Variants in Tobacco Addicted Patients of Pashtun Ethnicity of Khyber Pakhtunkhwa Province of Pakistan

Associations of GSTT1, GSTM1 and CYP1A1 gene variants with risk of developing oral cancer were evaluated in this study. A case-control study was conducted in Pashtun population of Khyber Pakhtunkhwa province of Pakistan in which 200 hospital based oral cancer cases and 151 population based healthy controls exposed to similar environmental conditions were included. Sociodemographic data were obtained and blood samples were collected with informed consent for analysis. GSTM1 and GSTT1 were analysed through conventional PCR method while specific RT-PCR method was used to detect CYP1A1 polymorphisms. Results were analyzed for conditional logistic regression model by SPSS version 20. The study shows that patients with either GSTM1 or GSTT1 null genotypes have significantly higher risk of oral cancer (adjusted odds (OR): (3.019 (1.861-4.898) and 3.011(1.865-4.862), respectively), which further increased when either one or both null genes were present in combination (adjusted odds (OR): (3.627 (1.981-6.642 and 9.261 (4.495-19.079), respectively). CYP1A1 rs4646903 gene variants individually showed weak association OR: 1.121 (0.717-1.752); however, in the presence of GSTM1 and/or GSTT1 null genotypes further increasing the association (adjusted odds (ORs): 4.576 (2.038-10.273), 5.593 (2.530-12.362) and 16.10 (3.854-67.260 for GSTM/GSTT null and CYP1A1 wild type, GSTM/GSTT either null and CYP1A1 variant alleles, and all 3 gene polymorphisms combinations, respectively). Our findings suggest that presence of GSTM1 and/or GSTT1 null genotypes along with variant alleles of CYP1A1 may be the risk alleles for oral cancer susceptibility in Pashtun population.

Microwave-assisted spent black tea leaves as cost-effective and powerful green adsorbent for the efficient removal of Eriochrome black T from aqueous solutions

Abstract In this work, microwave-assisted spent black tea leaves (MASTL) were used as effective low-cost green adsorbents for the removal of Eriochrome Black T (EBT) from aqueous solutions and adequately characterized. The pHpzc of MASTL was found to be 4.6. The experimental conditions, such as pH, contact time, temperature, adsorbent dose and EBT concentration, were optimized to evaluate the interaction of EBT with MASTL. The adsorption isotherms were simulated by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models. The results showed that the Langmuir model best fitted the adsorption data. The monolayer adsorption capacity was calculated to be 242.72 mg/g at 25 °C. The thermodynamic data calculated from the temperature-dependent adsorption isotherms indicated that the adsorption process was spontaneous, endothermic and physicochemical in nature. The results revealed that the MASTL could be used as low-cost green adsorbents for the efficient removal of EBT from aqueous solutions in environmental pollution clean-up.

Innovations in graphene-based nanomaterials in the preconcentration of pharmaceuticals waste

ABSTRACT Generally, pharmaceuticals (PhAs) have been extensively detected in various food and wastewater samples. In this regard, solid-phase extraction (SPE) is an excellent choice for their preconcentration, extraction, and fractionation. Typical, graphene-based nanomaterials (GBNMs) have been spaciously utilized as the efficient SPE adsorbents for the extraction of PhAs. Magnetic solid-phase extraction (MSPE) is found to reduce the time and cost of the operation by skipping the centrifugation step. Of note, this review summarizes the current research on the preconcentration of PhAs by GBNMs and provides valuable information about their applications in the determination and analysis of PhAs in various samples of health and environmental importance. Finally, the different analytical techniques used for the preconcentration of PhAs as well as their adsorption mechanism, and different environmental factors affecting the adsorption, have been studied and discussed in details. GRAPHICAL ABSTRACT

Erratum to: A High-Resolution LC–MS/MS Method for the Quantitative Determination of Artemether and Its Metabolite Dihydroartemisinin in Human Plasma and Its Application to Pharmacokinetic Studies

A highly sensitive and rapid liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of artemether and its metabolite dihydroartemisinin in human plasma using artemisinin as an internal standard. Chromatographic separation was achieved on a Supelco Discovery HS C18 RP column (150 mm × 4.6 mm, 5 µm; Bellefonte, USA) using acetonitrile and water with 0.1 % formic acid (80:20, v/v) as a mobile phase in isocratic mode. A high-resolution Thermo Electron Corporation LTQ-Orbitrap mass spectrometer (San Jose, USA) was used in single ion monitoring (SIM) mode using atmospheric pressure chemical ionization (APCI) as an interface. The following extracted ion ranges ([M + H]+) were monitored: m/z 267.14–267.16 for artemether, m/z 221.16–221.18 for dihydroartemisinin and m/z 283.14–283.16 for internal standard. The limit of detection (LOD) and limit of quantification (LOQ) for artemether were 0.3 and 0.8 ng mL−1, while for dihydroartemisinin were 0.2 and 0.6 ng mL−1, respectively. The validated method was successfully applied to the quantification of artemether and dihydroartemisinin in plasma samples of healthy volunteers participating in pharmacokinetic drug–food interaction studies.