Zenab Attari

Enhanced ex vivo intestinal absorption of olmesartan medoxomil nanosuspension: Preparation by combinative technology

The purpose of this study was to develop nanosuspension based on combinative technology to enhance the intestinal absorption of Olmesartan medoxomil (OLM), a potent antihypertensive agent with limited oral bioavailability. Two combinative approaches were employed and then characterized. In vitro intestinal absorption of OLM nanosuspension and plain OLM was studied using non-everted rat intestinal sac model. Optimal OLM nanosuspension was prepared by a combination of ball milling and probe sonication using stabilizer, Poloxamer 407. The formula exhibited particle size of 469.9 nm and zeta potential of −19.1 mV, which was subjected to ex vivo studies. The flux and apparent permeability coefficient in intestine from OLM nanosuspension was higher than the plain drug, thereby suggesting better drug delivery.

Formulation and characterisation of nanosuspensions of BCS class II and IV drugs by combinative method

Drug nanocrystals are known to increase the solubility of Biopharmaceutics Classification System (BCS) class II and IV drugs. SmartCrystals are the second generation nanocrystals with particle size of less than 100 nm and increased the stability and solubility of drug and drug product. The combinative methods adopted for the preparation of SmartCrystals are reported to shorten the processing time to reduce the particle size of the drug. This study was carried out with the aim to prepare nanosuspensions of aprepitant and ibuprofen using two pretreatment methods, precipitation and ball milling in a combination of high-pressure homogenisation (HPH). Ball milling and precipitation resulted in nanosuspensions having a particle size less than 1 µ, which were subjected to high HPH. HPH further led to a reduction in the particle size. However, the precipitation method failed to reduce the size of ibuprofen particles to 1 µ.

Subacute Toxicity Profile of Lacidipine Nanoformulation in Wistar Rats

The present study was aimed at investigating the safety of Lacidipine (LCDP) loaded nanostructured lipid carriers (NLCs) in Wistar rats. NLCs were formulated using ultrasound dispersion technique. Animals were orally treated once daily with NLCs containing 0.140 mg, 0.350 mg, and 0.875 mg of LCDP as low, medium, and high dose per kg body weight, respectively, during 28 days along with blank formulation and pure LCDP. Control rats were fed with water. Animals were observed throughout experiment period and their body weight was recorded once weekly. Overnight fasted rats were sacrificed on the 29th day. Study revealed no signs or symptoms of toxicity or morbidity. No significant changes in the body weight were observed between treated and control group. Significant increase in left testis weight and liver weight was observed in male and female rats, respectively. Haematological estimation revealed significant decrease in haemoglobin count in male rats while female rats showed significant increase in granulocyte count. All the serum clinical parameters were within the normal range and no gross histopathological changes were observed. No delayed effect was noted in satellite group. The results indicate that developed LCDP loaded NLCs are safe when administered orally in rats.

Preclinical efficacy of a gastro-sparing novel thiazolidin-4-one in alleviating secondary lesions of polyarthritis: A multi-parametric approach.

The promising role of thiazolidin-4-ones (TZOs) against inflammatory conditions has been reported. From our lab, one of the TZO derivatives, compound 4C, exerted anti-inflammatory potential via inhibition of locally released cytokines and prostaglandin. In continuance, a detailed study was undertaken for the preclinical profiling of this promising TZO derivative against polyarthritis in rats, along with assessment of risk associated with the treatment. Male Sprague-Dawley rats were used for the adjuvant-induced arthritis (AIA) model. Based on the development of secondary lesion, the animals were randomized into different treatment groups. To establish the efficacy of the test compound, parameters such as inflammation, pain, disease progression, cytokines and prostaglandin (PG)-E2 levels and complete blood cell profile were recorded along with radiological and histological examinations of joints. The study also focused on evaluating the side effect of test compound on gastric, liver, renal, blood and cardiovascular components. Compound 4C exerted promising therapeutic effect against secondary lesions in polyarthritis in rats. It limited the progression of chronic inflammation and associated pain in rats. Modulation of cytokine signalling and arachidonate metabolism by 4C was evident from inhibition of interleukin (IL)-6, tumor necrosis factor (TNF)-α and PGE2 generation in AIA rats. Comparatively, compound 4C was safer than diclofenac to cause gastric, liver, renal, blood and cardiovascular toxicities. These finding supports the efficacy and safety profile of 4C, a TZO derivative in limiting the progression of arthritis when administered orally.

Reversed-phase hplc method for determination of temozolomide in rat plasma and brain: simple, sensitive and robust method

A simple and sensitive HPLC method was developed and validated to detect an anti-glioma drug (temozolomide) in rat plasma and brain. The drug and internal standard (metronidazole) were eluted at proper retention times using BDS C18 column and selected mobile phase (ammonium formate – acetonitrile). The proposed method showed specificity and linearity with R2 values of 0.9964 and 0.9978 in plasma and brain, respectively. Other parameters such as intraday and interday precision were found to be within acceptable limits. The LOD and LOQ were 84 and 255 ng/mL, respectively. The drug recovery from the spiked plasma varied from 43 to 52%. Furthermore, stability of the method was evaluated and it was found that the drug exhibited good stability except at room temperature. The percentage recovery at room temperature after 24 h was within 69 – 73%; however, the drug was stable up to 15 days at –70°C.

Endothelium Dependent and Independent Mechanisms of Vasorelaxant Activity of Synthesized 2,5-disubstituted-1,3,4-oxadiazole Derivatives in Rat Thoracic Aorta – Ex vivo and Molecular Docking Studies

Background: Vasoconstriction is a major pathological feature of cardiovascular diseases involving endothelium dependent and independent mechanisms. Oxadiazole moiety appeared to be effective in various pathologies.Objective: The aim of the study was to synthesize and evaluate the mechanism of vasorelaxation exhibited by synthesized oxadiazole derivatives.Method: The 2,5-disubstituted-1,3,4-oxadiazole derivatives were synthesized by an efficient and simple method. The derivatives were investigated for their ex-vivo vasorelaxant action on intact/denuded endothelium rat aortic rings precontracted with norepinephrine/ phenylephrine/KCl.Results: The contractions induced in the aortic rings by the addition of cumulative concentrations of norepinephrine,phenylephrine, KCl and calcium were significantly antagonized by a derivative, OXD-Z2. In another experiment, verapamil pretreatment inhibited phenylephrine and Ca2+-induced aortic contractions and OXD-Z2 did not alter verapamilinduced inhibition. This indicated the role of L-type Ca2+-channels in the OXD-Z2-induced vasorelaxation via inhibition of calcium influx. Further, atropine (muscarinic receptor antagonist), L-NAME (NO synthase inhibitor) and methylene blue (non-selective cGMP inhibitor) inhibited OXD-Z2-induced relaxation in other sets of experiments. These results indicate that OXD-Z2 also mediates vasorelaxation through NO release by muscarinic receptor activation. In addition, the molecular docking studies showed that OXD-Z2 interacts with L-type Ca2+-channel, muscarinic (M2) receptor and eNOS.Conclusion: Thus, it is deduced from the above findings that the vasorelaxant activity of OXD-Z2 involves muscarinic receptor-mediated nitric oxide release in addition to direct inhibition of L-type Ca2+-channels.

Acyclovir Entrapped N-Trimethyl Chitosan Nanoparticles for Oral Bioavailability Enhancement

Objective: The aim of the study was to evaluate a nanoparticulate system composed of Ntrimethyl chitosan (TMC) for improving the oral bioavailability of Acyclovir (ACV). Methods: TMC was prepared by methylation of chitosan and characterized by H-NMR spectroscopy. The ionic gelation method was used to prepare ACV loaded TMC nanoparticles. Non-everted sac technique was used to assess ex vivo permeation in rats. A pharmacokinetic study of the optimized formulation was carried out in male Wistar rats in comparison with ACV alone. Results: Ex vivo studies exhibited a significant rise in the permeation of ACV from the rat intestinal membrane when formulated as nanoparticles. The results showed an increase in plasma concentration of ACV from the nanoformulation and significant difference (p < 0.05) in pharmacokinetic parameters as compared to pure drug, ACV. Conclusion: The results suggest that higher oral delivery of ACV can be achieved by combining the benefits of both TMC and nanoparticles.