DARU, Journal of Pharmaceutical Sciences
Volume:16 Issue: 2, Summer 2008

Abstract: Several di-substituted 2-hydroxyacetamides have shown promising anti-mycobacterial activity. In an attempt for further development of these compounds which are easily synthesized, investigation of the relationship between their physicochemical properties and inhibitory activities appeared of interest. Since lipophilicity as a physicochemical parameter plays an important role on biological activity and drug design, the relationship between partition coefficient as a measure of lipophilicity and antimycobacterial activity of the studied compounds was investigated. Partition coefficients of 2-hydroxyacetamides a-n measured by the shake flask (log P), reversed-phase high-performance liquid chromatography (RP-HPLC log k) methods and by theoretical calculation (ClogP) were compared and the relationship between the resulting values and antimycobacterial activities of the studied compounds determined by Alamar Blue Assay was investigated. When all compounds were included in the correlation analyses, no significant relationship between MICs (minimum inhibitory concentrations) and lipophilicity parameters was observed, but HPLC values showed significant correlation with ClogP. The best correlation between MICs and lipophilicity parameters for di-substituted amides g-n which were more active than mono -substituted amides were RP-HPLC based log k and for mono-substituted amides were shake flask log P values which in both cases were not significant. When deviating compounds m and n were excluded from the correlation analyses, for di-substituted amides, correlation between MICs and log k as well as correlation between values of partition coefficient by different methods became significant. Results of this investigation indicates that both ClogP and log k are equally suitable for prediction of partition coefficient.

Abstract: Background and purpose of the study: Verapamil hydrochloride is a calcium channel blocker which is used in the control of supraventricular arrhythmia, hypertension and myocardial infraction. There are considerable inter-individual variations in serum concencentration of verpamil due to variation in the extent of hepatic metabolism. In this study controlled-release buccoadhesive tablets of verapamil hydrochloride (VPH) were prepared in order to achieve constant plasma concentrations, to improve the bioavailability by the avoidance of hepatic first-pass metabolism, and to prevent frequent administration. Tablets containing fixed amount of VPH were prepared by direct compression method using polymers like carbomer (CP), hydroxypropylmethyl cellulose (HPMC) and sodium carboxymethyl cellulose (NaCMC) in various combination and ratios and evaluated for thickness, weight variation, hardness, drug content uniformity, swelling, mucoadhesive strength, drug release and possible interaction between ingredients. All tablets were acceptable with regard to thickness, weight variation, hardness, and drug content. The maximum bioadhesive strength was observed in tablets formulated with a combination of CP-NaCMC followed by CP-HPMC and NaCMC-HPMC. Decreasing the content of CP in CP-HPMC tablets or NaCMC in CP-NaCMC or NaCMC-HPMC systems resulted in decrease in detachment forces. Lower release rates were observed by lowering the content of CP in CP-HPMC containing formulations or NaCMC in tablets which contained CP-NaCMC or NaCMC-HPMC. The release behavior was non-Fickian controlled by a combination of diffusion and chain relaxation mechanisms and best fitted zero-order kinetics. The buccoadhesive VPH tablets containing 53% CP and 13.3% HPMC showed suitable release kinetics (n = 0.78, K0 zero order release = 4.11 mg/h, MDT = 5.66 h) and adhesive properties and did not show any interaction between polymers and drug based on DCS scanning. This buccoadhesive system may be useful for buccal administration of VPH.

Background and purpose of the study: There is great interest for researchers and therapists to study the interactions of phenytoin with other drugs or foods because of its enzyme inducing effects, saturable biodisposition and specific physicochemical properties. There are reports indicating that ascorbic acid (ASC) affects interacting properties of phenytoin. By considering pharmacokinetic aspects, the present study was carried out to evaluate the effect of ASC on single and multiple dose kinetics of phenytoin in rats. Male Wistar rats weighting 200-225 g were randomly divided into 9 groups of 6. In groups 1 to 3, phenytoin was administered orally (p.o.) (30 mg/kg) for a week and saline (5 ml/kg) and ASC (200, 500 mg/kg) were given p.o. one hour before each phenytoin treatment respectively. In groups 4 and 5, animals were treated with saline and ASC (500 mg/kg) for a week and one hour before single dose of phenytoin (30 mg/kg). In groups 6 and 7, single dose of phenytoin was administered p.o. (60 mg/kg) whereas normal saline and ASC (500mg/kg) were administered concurrently intraperitoneally (i.p.). In groups 8 and 9, single dose of phenytoin (60 mg/kg) was administered i.p., whereas other treatments were similar to groups 6 and 7. Blood samples were taken at 0, 1, 2, 3, 4, 6, 8 and 12 hours after phenytoin administration and analyzed by HPLC method. It was found that AUC0-∞, AUC0-t, Cmax, Tmax, and T1/2 didn''t change significantly in the test groups compared to the respected controls. Tmax and T1/2 were only parameters showed a significant increase in groups 3 and 5 compared to control groups. Acidic change in gut lumen and/or renal tubules may explain these interactions. Results of this study indicate that ASC has no significant interaction with phenytoin bioavailability.

Abstract: Bakground and purpose of the study: Hydroxypyridin-4-ones, a group of iron chelators have shown promise as potential compounds for the treatment of iron overload by the oral route. Their selectivity and high complex formation constant with iron makes them good candidates for iron determination. In this study the use of N-ethyl-2-methyl-3-hydroxy-pyridin-4-on (EMHP), a strong and selective ferric chelator, as a new ligand for measurement of µmolar concentrations of iron in aqueous solutions and biological fluids was investigated. This measurement is based on the color reaction of Fe3+ with EMHP. After mixing serum sample and reagent, and incubating at room temperature, the absorbance of the resulting complex was measured at lmax. The effect of analytical variables, such as the amount and the kind of the reagents, pH, ratio of EMHP/Fe (III) and presence of other ions in determination of iron were studied. The results showed that the optimum wavelength for the measurement was 456 nm. Formation of the complex was completed in less than 20 min and it was stable up to 24 hrs. Molar ratio of 6-10 EMHP/Fe (III) and pH = 5 were the optimum conditions for complex formation and determination of Fe (III). The detection limit was 2.5×10-6 M of Fe (III) in serum or plasma. Ions commonly associated with iron did not interfere in the present method. This method which is simple and reproducible was found sensitive for determination of Fe (III) in several real samples at micromolar levels.

Abstract: Antioxidants are vital substances which possess the ability to protect the body from damages caused by free radical-induced oxidative stress. A variety of free radical scavenging antioxidants are found in dietary sources like fruits, vegetables and tea. The purpose of this study was to evaluate the antioxidant activity of methanolic extracts of 24 selected plant materials (seeds or fruits), which are used by Iranian people as folk remedies and/or food supplements. The antioxidant activity was evaluated against linoleic acid peroxidation using 1,3-diethyl-2-thiobarbituric acid as reagent. At the same time the phenolic content of the extracts was determined using Folin-Ciocalteau reagent to evaluate their contribution to total antioxidant activity. The antioxidant activity expressed as IC50 ranged from 1.25 mg/ml in cucumber to 167.29 mg/ml in cardamom. Phenolic contents, expressed as gallic acid equivalents, varied from 21.76 mg/100g of the dried weight in linseed to 919.12 mg/100 g of the dried weight in Bishop''s weed. No significant correlation was observed between antioxidant activity and phenolic content in the studied plant materials. The results of this study showed that there is no significant correlation between antioxidant activity and phenolic content of the studied plant materials and phenolic content could not be a good indicator of antioxidant capacity.

Abstract: Background and the purpose of study: Anethum graveolens L. (Umbilliferae) is used in Iranian folk medicine as an anti-hypercholesterolaemic plant. The present study was carried out to determine the effect of Anethum graveolens extract (AGE) on serum lipoproteins in hypercholesterolaemic rats and also to determine its mechanism of action to some extant on liver hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase activity. The changes in serum triglyceride (TG), total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C) and low density lipoprotein-cholesterol (LDL-C) were measured using enzymatic kits. Hepatic HMG-CoA reductase activity was indirectly measured by the HMG CoA/mevalonate ratio. The amount of total phenolic and flavonoid compounds were also determined by common colorimetric methods. Keeping the rats on a high-fat diet for 7 consecutive days increased the serum TC, TG and LDL-C levels significantly. However, the HDL-C level decreased relative to normal rats. Treatment of hyperlipidaemic rats with AGE (single daily dose of 1 ml, equivalent to 500 mg of the plant powder) and high-fat diet for up to 10 and/or 30 days reversed the serum lipid levels compared to rats which were fed only high-fat diet. In addition, our data indicated significant increase in HMG-CoA/mevalonate ratio as compared to rats which were fed high-fat diet after treatment with AGE for 30 days, indicating a decrease in the enzyme activity. Experiments showed that AGE has the phenolic and flavonoid content of 105.2 mg of gallic acid equivalents/g of the dried extract and 58.2 mg of catechin equivalents/g of the dried extract, respectively. The cumulative results clearly indicate that A. graveolens possesses potent hypocholesterolaemic effects in rats probably mediated through the suppression of endogenous cholesterol biosynthesis by inhibition of the activity of HMG-CoA reductase.

Abstract: Free radicals derived from molecular oxygen have been reported to be responsible for changes in motility and mucosal damages observed in intestinal Ischemia-Reperfusion (I/R) injury. Melatonin has been considered as an antioxidant that prevents injuries resulting from Ischemia/Reperfusion in various tissues. This study was designed to determine the effects of melatonin at a dose dependent manner in intestinal I/R damages by contractile responses of Malondialdehyde (MDA), a product of lipid peroxidation in rats. A total of 36 young male Wistar - Albino rats (80 - 120 g) were divided equally in to 6 groups and subjected to different concentration of melatonin (10, 20, 30 mg/Kg). Group 1 was control, group 2 was sham that were subjected to surgical process for Superior Mesenteric Artery (SMA) dissection. Groups 3, 4, 5 and 6 were I/R that were given melatonin at 0, 10, 20 and 30 mg/kg respectively. After laparatomy, a microvascular traumatic clip was placed across the SMA under general anesthesia, and following ischemia for 30 minutes it was removed. The first dose of melatonin was administrated before, and the second dose was administrated just after reperfusion, and the third dose was administrated on the second day, all by intramuscular route. On the third day of the experiment all rats were killed, and their bowels were removed. The levels of tissue malondialdehyde were found to be significantly lower in group 4 compared to group 3 (P < 0.05).There was significant differences in histopathological patterns of group 4 compared with group 3 (P < 0.01). MDA levels, in groups 5 and 6, showed no significant changes in comparison to I/R group. These results showed that Melatonin at dose of 10 mg/Kg has antioxidant effects and prevents rat intestinal ischemia - reperfusion damages.

Abstract: Evaluation of bioactivity of recombinant erythropoietin is essential for pharmaceutical industry, quality control authorities and researchers. The purpose of this study was to compare real time RT-PCR and flow cytometry for the assay of biological activity of recombinant erythropoietin. Three concentrations of recombinant erythropoietin BRP (80, 40 and 20 IU/ml) were injected subcutaneously to mice. After 4 days the blood was collected and used for reticulocyte counts by flow cytometry and also for the RNA extraction. Real time RT-PCR amplification was carried out for β-globin. Results and There was a significant correlation between the total RNA amounts (R2= 0.9995), relative quantity of β-globin mRNA (R2= 0.984) and reticulocyte counts (R2= 0.9742) with rhEpo concentrations. Total RNA and quantitative RT-PCR showed significant dose dependent results as well the reticulocyte counts by flow cytometry for the biological activity assay of rhEpo and so these methods could be considered as alternatives for flow cytometry.

Abstract: Background and the purpose of the stud:, Lipocalin 2 (Lcn2, NGAL) is a member of the lipocalin super family which has been known as an early marker for ischemic acute renal injury and cisplatin nephrortoxicity. In this study the ability of Lcn2 to prevent cisplatin-induced toxicity was studied. Lcn2 cDNA was isolated from Hep G2 cell line and cloned to pcDNA3.1(+) vector. The construct was trasnfected to CHO cell line. Stable clones were generated and the expression of Lcn2 was determined by RT-PCR and ELISA. Lcn2 gene in A549 cell line was also down-regulated with the siRNA. CHO and A549 cells were exposed to cisplatin and cell proliferation was determined by MTT assay. Cell proliferation was higher in CHO expressing Lcn2 at doses of 75, 150, and 200 μg/ml of cisplatin after 48 h compared with control. Cisplatin toxicity increased significantly in A549 cells following treatment with Lcn2 siRNA. Major findings of this study revealed that Lcn2 acts as a cytoprotective factor against cisplatin toxicity and suggests that Lcn2 might have the potential application to ameliorate the cisplatin toxicity.

Abstract: Background and purpose of the study: There are considerable efforts to identify naturally occurring substances as new drugs in cancer therapy. Many components from dietary or medicinal plants have been identified that possess substantial chemopreventive properties. Iran has unique plant varieties yet to be studied for anticancer components. Therefore, anticancer effects and cell cycle alterations caused by Astrodaucus persicus (Boiss.) Drude, an Iranian species of family of Umbelliferae, in human breast cancer T47D cells was investigated. The T47D cells were seeded in 96-well culture plates in the presence and absence of different concentrations of either aerial or root extracts of A. persicus to determine their anticancer effects in comparison to doxorubicin using MTT assay. The changes in the cell cycle pattern of T47D cells using DAPI reagent in flow cytometric analysis was also studied. Both extracts of A. persicus showed strong antiproliferative effects on T47D cells when compared to RPMI control and doxorubicin. The cytotoxicity of the root extract was greater than aerial extract of A. persicus. Both extracts showed pattern of cell cycle relatively similar to RPMI and significantly different from doxorubicin. These data are first report on potential anticancer activity of A. persicus extracts and its possible mechanism of action on cancer cell proliferation.