Development and Validation of a Novel RP-HPLC Analytical Method for Sitagliptin Determination in Human Plasma

Background: Different bio-analytic methods have been developed for determining drug concentration in plasma, but methods for sitagliptin determination are still very rare. In this study, RP-HPLC based method has been developed for assessing sitagliptin concentration in plasma. Aim: To develop and validate RP-HPLC based analytical method for estimating sitagliptin in human plasma for pharmacokinetic applications. Methods: In the present study, the mobile phase composed of acetonitrile: 0.5% triethanolamine (20:80) with pH 6.5 has been utilized. Samples of plasma containing sitagliptin and internal standard (IS)-rosiglitazone were extracted with dichloromethane:diethyl ether (4:6; v/v) at pH 7.4. The rate of flow was 1 ml/min. The retention time was about 5,232 and 6,903 minutes respectively for sitagliptin and rosiglitazone. Results: At concentrations of 100-3200 ng/ml in plasma, calibration curves of sitagliptin were linear. The inter- and intra-day precision and accuracy ranged in between 93.56-98.56% and 1.09-4.55% respectively. For specificity, the study findings showed no co-eluting peaks occurring with IS drug (rosiglitazone) and confirmed that no percentage of interferences at analyte (sitagliptin) retention in presence of rosiglitazone. The sitagliptin recovery was 96.442%. Chromatographic separations were performed on HI Qsil C-18 HS column (250mm x 4.6mm x 5μm). The stability of stock solutions of sitagliptin and IS at room temperature was 98.06% and 100.79% respectively while under refrigerated conditions stability was 98.19% and 96.59% respectively. Freeze-thaw stability for sitagliptin was performed with low & high QC and shown as 98.26% for and 97.45% respectively. The limits of detection and quantification were 8.592 ng/ml and 28.641 ng/ml respectively. Conclusion: A simple, sensitive and accurate method was developed for bio analytical estimation of sitagliptin in human plasma using liquid-liquid extraction technique. The validation results of linearity, accuracy, precision, stability, selectivity, ruggedness, LOD and LOQ were good under acceptable limit and can be applied for pharmacokinetic studies.

Role of drugs in the prevention and amelioration of radiation induced toxic effects

As the use of radiation technology for nuclear warfare or for the benefits of mankind (e.g. in radiotherapy or radio-diagnosis) is increasing tremendously, the risk of associated side effects is becoming a cause of concern. These effects, ranging from nausea/vomiting to death, may result from accidental or deliberate exposure and begin in seconds. Through this review paper, efforts have been done to critically review different compounds which have been investigated as radioprotectors and radiation mitigators. Radioprotectors are compounds which are administered just before or at the time of irradiation so as to minimize the radiation induced damage to normal tissues. And radiation mitigators are the compounds which can even minimize or ameliorate post irradiaion-toxicity provided they are administered before the onset of toxic symptoms. A variety of agents have been investigated for their preventive and ameliorative potential against radiation induced toxic effects. This review article has focused on various aspects of the promising representative agents belonging to different classes of radioprotectors and mitigators. Many compounds have shown promising results, but till date only amifostine and palifermin are clinically approved by FDA. To fill this void in pharmacological armamentarium, focus should be shifted towards novel approaches.

Effect of goat milk on hepatotoxicity induced by antitubercular drugs in rats

Aim of the present study was to assess the hepatoprotective activity of goat milk on antitubercular drug-induced hepatotoxicity in rats. Hepatotoxicity was induced in rats using a combination of isoniazid, rifampicin, and pyrazinamide given orally as a suspension for 30 days. Treatment groups received goat milk along with antitubercular drugs. Liver damage was assessed using biochemical and histological parameters. Administration of goat milk (20 mL/kg) along with antitubercular drugs (Group III) reversed the levels of serum alanine aminotransferase (82 ± 25.1 vs. 128.8 ± 8.9 units/L) and aspartate aminotransferase (174.7 ± 31.5 vs. 296.4 ± 56.4 units/L, p < 0.01) compared with antitubercular drug treatment Group II. There was a significant decrease in serum alanine aminotransferase (41.8 ± 4.1 vs. 128.8 ± 8.9 units/L, p < 0.01) and aspartate aminotransferase (128.8 ± 8.54 vs. 296.4 ± 56.4 units/L, p < 0.001) levels in Group IV (goat milk 40 mL/kg) compared with antitubercular drug treatment Group II. Goat milk (20 mL/kg and 40 mL/kg) was effective in reversing the rise in malondialdehyde level compared with the antitubercular drug suspension groups (58.5 ± 2 vs. 89.88 ± 2.42 μmol/mL of tissue homogenate, p < 0.001 and 69.7 ± 0.78 vs. 89.88 ± 2.42 μmol/mL of tissue homogenate, p < 0.001, respectively). Similarly, both doses of milk significantly prevented a fall in superoxide dismutase level (6.23 ± 0.29 vs. 3.1 ± 0.288 units/mL, p < 0.001 and 7.8 ± 0.392 vs. 3.1 ± 0.288 units/mL, p < 0.001) compared with the group receiving antitubercular drugs alone. Histological examination indicated that goat milk reduced inflammation and necrotic changes in hepatocytes in the treatment groups. The results indicated that goat milk prevented the antitubercular drug-induced hepatotoxicity and is an effective hepatoprotective agent.

Dual inhibition: a novel promising pharmacological approach for different disease conditions

To overcome the problems associated with polypharmacy, which include medication non compliance, adverse drug reactions, drug-drug interactions and increased pill-burden, various strategies, such as sustained-release drugs and fixed-dose combination regimens (polypills), have been developed. Out of these, a novel and very much promising approach is the use of dual-action drugs. Amongst the dual-action drugs, there is a class of compounds known as dual inhibitors, which possess the dual inhibitory activity. The most common examples of dual inhibitors are rivastigmine, ladostigil, asenapine, phenserine, amitriptyline, clomipramine, doxepin and desipramine. This review article focuses on the conventional drugs used in different diseases which possess dual inhibition activity as well as those which are still in the preclinical/clinical phase.

Bacteria in cancer therapy: a novel experimental strategy

Resistance to conventional anticancer therapies in patients with advanced solid tumors has prompted the need of alternative cancer therapies. Moreover, the success of novel cancer therapies depends on their selectivity for cancer cells with limited toxicity to normal tissues. Several decades after Coley's work a variety of natural and genetically modified non-pathogenic bacterial species are being explored as potential antitumor agents, either to provide direct tumoricidal effects or to deliver tumoricidal molecules. Live, attenuated or genetically modified non-pathogenic bacterial species are capable of multiplying selectively in tumors and inhibiting their growth. Due to their selectivity for tumor tissues, these bacteria and their spores also serve as ideal vectors for delivering therapeutic proteins to tumors. Bacterial toxins too have emerged as promising cancer treatment strategy. The most potential and promising strategy is bacteria based gene-directed enzyme prodrug therapy. Although it has shown successful results in vivo yet further investigation about the targeting mechanisms of the bacteria are required to make it a complete therapeutic approach in cancer treatment.

Lacosamide, a newer antiepileptic

Lacosamide (LCM) is a newer antiepileptic drug with a dual mode of action. It selectively enhances slow inactivation of voltage-gated sodium channels without affecting fast inactivation, and modulates collapsing response mediator protein 2 (CRMP-2). It has a high oral bioavailability of approximately 100%. It has shown potent and broad neuroprotective effects in vitro and in vivo animal models making it a potential candidate for long term treatment of epilepsy. In addition to this, it has demonstrated analgesic activity in various animal models. Apart from this, LCM has demonstrated potent effects in animal models for a variety of CNS disorders like schizophrenia and stress induced anxiety. Various safety pharmacology and toxicology studies have shown that LCM is well tolerated. Clinical trials have also suggested that LCM is a safe, effective, and well tolerated adjunctive treatment for reduction of seizure frequency in patients with highly refractory, partial seizures. Other potential indications of LCM are being investigated.

Pharmacokinetic and toxicological profile of artemisinin compounds: an update

Artemisinin has been used effectively in malaria treatment. With the emerging resistance to malaria, the optimum and judicial use of the drug has become important. The drug metabolism and toxicology can have an impact on the therapeutic profile and clinical use of this antimalarial agent. In this review, we discuss the pharmacokinetics and toxicological aspects of artemisinin and its therapeutic implications. Artemisinins have several dosing routes including oral, intramuscular, intravenous and rectal. With repeated dosing, artemisinin has propensity for autoinduction, leading to decreased plasma levels on repeated dosing. Combination with other antimalarials in most cases did not influence the pharmacokinetics of artemisinins. Interactions with cytochrome P(450) inhibitors are known but these neither affect the efficacy nor the toxicity of the respective derivative. Artemisinins are generally regarded to be of low toxicity. Two major problems associated with them are neurotoxicity and reproductive toxicity. But the extent of this neurotoxicity is dependent on the nature of the compound, on the route of administration, and on the nature of the formulation. Moreover, it occurs in humans at very high doses. However, as a matter of precaution, the use of artemisinins in the first trimester of pregnancy has been contraindicated.