simple and specific stability- indicating RP-HPLC method for routine assay of adefovir dipivoxil in bulk and tablet dosage form

A simple and reliable stability-indicating RP-HPLC method was developed and validated for analysis of adefovir dipivoxil [ADV].The chromatographic separation was performed on a C[18] column using a mixture of acetonitrile-citrate buffer [10 mM at pH 5.2] 36:64 [%v/v] as mobile phase, at a flow rate of 1.5 mL/min. Detection was carried out at 260 nm and a sharp peak was obtained for ADV at a retention time of 5.8 +/- 0.01 min. No interferences were observed from its stress degradation products. The method was validated according to the international guidelines. Linear regression analysis of data for the calibration plot showed a linear relationship between peak area and concentration over the range of 0.5-16 micro g/mL; the regression coefficient was 0.9999 and the linear regression equation was y = 24844x-2941.3. The detection [LOD] and quantification [LOQ] limits were 0.12 and 0.35 micro g/mL, respectively. The results proved the method was fast [analysis time less than 7 min], precise, reproducible, and accurate for analysis of ADV over a wide range of concentration. The proposed specific method was used for routine quantification of ADV in pharmaceutical bulk and a tablet dosage form

Design, synthesis and biological evaluation of4-[imidazolylmethyl]-2-[4-methylsulfonyl phenyl]-quinoline derivatives as selective COX-2 inhibitors and in-vitro anti-breast cancer agents

A new group of 4-[Imidazolylmethyl] quinoline derivatives possessing a methylsulfonyl COX-2 pharmacophore at the para position of the C-2 phenyl ring were designed and synthesized as selective COX-2 inhibitors and in-vitro anti breast cancer agents. In-vitro COX-1 and COX-2 inhibition studies showed that all the compounds were potent and selective inhibitors of the COX-2 isozyme with IC[50] values in the potent range 0.063-0.090 microM, and COX-2 selectivity indexes in the 179.9 to 547.6 range. Molecular modeling studies indicated that the methylsulfonyl substituent can be inserted into the secondary pocket of COX-2 active site for interactions with Arg[513]. Cytotoxicity of quinolines 9a-e against human breast cancer MCF-7 and T47D cell lines were also evaluated. All the compounds 9a-e were more cytotoxic against MCF-7 cells in comparison with those of T47D which express aromatase mRNA less than MCF-7 cells. The data showed that the increase of lipophilic properties of substituents on the C-7 and C-8 quinoline ring increased their cytotoxicity on MCF-7cells and COX-2 inhibitory activity. Among the quinolines 9a-e, 4-[[1H-Imidazol-1-yl]methyl] 7,8,9,10-tetrahydro-2-[4-methylsulfonylphenyl]-benzo[h]quinoline [9d]was identified as the most potent and selective COX-2 inhibitor as well as the most cytotoxic agent against MCF-7 cells

Design, synthesis and cytotoxicity evaluation of new 1,2-diaryl-4, 5, 6, 7-tetrahydro-1H-benzo[d] imidazolesas tubulin inhibitors

A new series of 1,2-diaryl-4,5,6,7-tetrahydro-1H-benzo[d]imidazoles, possessing trimethoxyphenyl pharmacophore, were synthesized to evaluate their biological activities as tubulin inhibitors. Cytotoxic activity of the synthesized compounds 7a-f was assessed against several human cancer cell lines, including MCF-7 [breast cancer cell], HEPG2 [liver hepatocellular cells], A549 [adenocarcinomic human alveolar basal epithelial cells], T47D [Human ductal breast epithelial tumor cell line] and fibroblast. According to our results, HEPG2 seems to be the most sensitive, while MCF7 was the most resistant cell line to the compounds. All the compounds expect 7b, possessed satisfactory activity against HEPG2 with mean IC[50] values ranging from 15.60 to 43.81 micro M

In-silico investigation of tubulin binding modes of a series of novel antiproliferative spiroisoxazoline compounds using docking studies

Interference with microtubule polymerization results in cell cycle arrest leading to cell death. Colchicine is a well-known microtubule polymerization inhibitor which does so by binding to a specific site on tubulin. A set of 3, 4-bis [substituted phenyl]-4H-spiro [indene-2, 5-isoxazol]-1[3H]-one derivatives with known antiproliferative activities were evaluated for their tubulin binding modes. 3D structures of the derivatives were docked into the colchicine binding site of tubulin using GOLD 5.0 program under flexible ligand and semi-flexible receptor condition. The spiroisoxazoline derivatives bind tubulin in a similar manner to colchicine by establishing at least a hydrogen bonding to Cys[241] as well as hydrophobic interactions with Leu[255], Ile[378] and Lys[254] and few other residues at the binding pocket. It can be concluded that the spiroisoxazoline core structure common to the studied derivatives is a suitable scaffold for placing the antitubulin pharmacophoric groups in appropriate spatial positions required for tubulin binding activity

QSAR study on anti-HIV-1 activity of 4-Oxo-1,4-dihydroquinoline and 4-Oxo-4H-pyrido[1,2-a]pyrimidine derivatives using SW-MLR, artificial neural network and filtering methods

Predictive quantitative structure-activity relationship was performed on the novel4-oxo-1,4-dihydroquinoline and 4-oxo-4H-pyrido[1,2-a]pyrimidine derivatives to explore relationship between the structure of synthesized compounds and their anti-HIV-1 activities. In this way, the suitable set of the molecular descriptors was calculated and the important descriptors using the variable selections of the stepwise technique were selected. Multiple linear regression [MLR] and artificial neural network [ANN] as nonlinear system were used for constructing QSAR models. The predictive quality of the quantitative structure-activity relationship models was tested for an external set of five compounds, randomly chosen out of 25 compounds. The findings exhibited that stepwise-ANN model was more efficient at prediction activity of both training and test sets with high statistical qualities. Based on QSAR models results, electronegativity, the atomic masses, the atomic van der Waals volumes, the molecular symmetry and polarizability were found to be important factors controlling the anti-HIV-1 activity

Search for the pharmacophore of histone deacetylase inhibitors using pharmacophore query and docking study

Histone deacetylase inhibitors have gained a great deal of attention recently for the treatment of cancers and inflammatory diseases. So design of new inhibitors is of great importance in pharmaceutical industries and labs. Creating pharmacophor models in order to design new molecules or search a library for finding lead compounds is of great interest. This approach reduces the overall cost associated with the discovery and development of a new drug. Here we elaborated an exact pharmacophore model for histone deacetylase inhibitors by using pharmacophore query and docking study. The data set used for the modelling exercise comprised of 383 molecules collated from the original literature. These molecules were used to crating the model and docking study was held with Zolinza, the recently FDA approved drug as potent histone deacetylase inhibitor. Our model consists of 5 features: Hydrogen bond donors, Hydrogen bond acceptors, H-bond donor/acceptors, Aromatic ring centers, and hydrophobic centers. With the aid of this pharmacophore model and docking result, 3D searches in large databases can be performed, leading to a significant enrichment of active analogs

Design, synthesis and biological evaluation of 5-Oxo-1,4,5,6,7,8 hexahydroquinoline derivatives as selective cyclooxygenase-2 inhibitors

A group of regioisomeric 5-oxo-1,4,5,6,7,8 hexahydroquinoline derivatives possessing a COX-2 SO[2]Me pharmacophore at the para position of the C-2 or C-4 phenyl ring, in conjunction with a C-4 or C-2 phenyl [4-H] or substituted-phenyl ring [4-F,4-Cl,4-Br,4-OMe,4-Me, 4-NO[2]], were designed for evaluation as selective cyclooxygenase-2 [COX-2] inhibitors. These target 5-oxo-1,4,5,6,7,8 hexahydroquinolines were synthesized via a Hansch condensation reaction. In vitro COX-1/COX-2 isozyme inhibition structure-activity studies identified 7,8-dihydro-7,7-dimethyl-2-[4-methoxyphenyl]-4-[4-[methylsulfonyl]phenyl]quinolin-5[1H,4H,6H]-one [9c] as a potent COX-2 inhibitor [IC[50] = 0.17 M] with a high COX-2 selectivity index [S.I. = 97.6] comparable to the reference drug celecoxib [COX-2 IC[50] = 0.05 mM; COX-2 S.I= 405]. A molecular modeling study where 9c was docked in active site of COX-2 showed that the p-SO[2]Me substituent on the C-2 phenyl ring is inserted into the secondary COX-2 binding site. The structure activity data acquired indicate that the position of the COX-2 SO[2]Me pharmacophore and type of substituent are important for COX-2 inhibitory activity

Design, synthesis and cytotoxicity evaluation of new 2-aryl-5, 6-dihydropyrrolo[2, 1-a]isoquinoline derivatives as topoisomerase inhibitors

Two set of 2-aryl-5, 6-dihydropyrrolo [2,1-a] isoquinolines were designed and synthesized to evaluate their biological activities as topoisomerase inhibitors. Cytotoxic activity of the synthesized compounds 4a-e and 7a-d was assessed against several human cancer cell lines, including MCF-7 [breast cancer cell], HepG2 [liver hepatocellular cells], A549 [adenocarcinomic human alveolar basal epithelial cells], T47D [Human ductal breast epithelial tumor cell line] and Hela [Human cervix cancer]. According to our results, HepG2 seems to be the most sensitive cell line for these compounds with mean IC[50] values ranging from 4.25 to 70.05 micro M. Our results indicated that compound 7b exhibited the best potency against the tested cell lines. These results also suggest that pyrroloisoquinoline moiety constitutes a suitable scaffold to design new anti-proliferative agents

Occurrence of deoxynivalenol in foods for human consumption from Tehran, Iran

The occurrence of deoxynivalenol [DON] in retail foods in Tehran [Iran] was determined using high-performance liquid chromatography technique and immunoaffinity column as the clean-up step. A method was validated for analysis of DON in rice, bread, puffed corn snack and wheat flour. The average recoveries and precision [RSD] for DON in different foods ranged 84.2-93.1% and 2.9-12.0%, respectively. A survey of DON was performed on the 72 samples of rice, bread, puffed corn snack, and wheat flour collected from Tehran retail market. The data showed that 10 samples [13.9%] out of 72 samples were contaminated with DON with the maximum level of 368.7 ng/g. The samples had contamination level lower than the maximum tolerated level of DON in foods in Iran. The total intake of DON was under the provisional maximum tolerable daily intake set for DON by the JECFA

Cytotoxicity of selected novel chalcone derivatives on human breast, lung and hepatic carcinoma cell lines

Cancer is considered as a challenging deathly disease and discovering or synthesis of new cytotoxic agents is a worldwide attempt. In this study, a group of recently synthesized chalcones, with the structure of 1,3-diarylprop-2-en-1-one having differesnt COX-1 and/or COX-2 selectivities, have been examined on human hepatocarcinoma [HepG2], lung carcinoma [A549], and breast adenocarcinoma [MCF-7] cell line, using Sulforhodamine B [SRB] assay. Briefly, cells were treated with 1-100 microM of each compound for 72, 96 and 168 hours. In each case, a control row was set with the exposure of cells to compounds-free solvents. Median lethal concentration [LC50] values [compared to controls] were calculated using regression fitness analysis on GraphPad Prism® software. Our results show that the subgroup possessing p-azido COX-2 pharmacophore seems to be more cytotoxic, while the cells seem to show more acquired resistance to them and the subgroup possessing a p-MeSO2NH COX-2 pharmacophore is less cytotoxic, while the cells also acquire less resistance to them. In conclusion, considering the diversity in COX-1 or COX-2 inhibition among these compounds in each group, and also revealing no correlation between COX inhibition selectivity and cell death, it seems that selective inhibition of each isoenzyme doesn't cause substantial effect on toxicity potency. Further studies to determine the main mechanism[s] for these compounds induced cell death are encouraged

Rapid high performance liquid chromatographic method for determination of clarithromycin in human plasma Using amperometric detection: application in pharmacokinetic and bioequivalence studies

A rapid, sensitive and reproducible HPLC method using amperometric detector was developed and validated for the analysis of clarithromycin in human plasma. The separation was achieved on a monolithic silica column [MZ- C8 125×4.0 mm] using acetonitrile- methanol-potassium dihydrogen phosphate buffer [40:6:54,v/v], with pH of 7.5, as the mobile phase at a flow rate of 1.5 mL/min. The assay enables the measurement of clarithromycin for therapeutic drug monitoring with a minimum quantification limit of 20 ng/mL. The method involves simple, protein precipitation procedure and analytical recovery was complete. The calibration curve was linear over the concentration range of 0.1-6 [micro]g/mL. The coefficients of variation for inter-day and intra-day assay were found to be less than 6%. This method was used in bioequivalency and pharmacokinetic studies of the test [generic] product 2 × 500 mg clarithromycin tablets, with respect to the reference product

Improvement of capillary electrophoretic enantioseparation of fluoxetine by a cationic additive

One of the problems encountered in CE separations of basic compounds is the adsorption of analytes in negatively charged capillary wall which could lead to poor repeatability of migration time and peak area. Additionally, separation of enantiomers of chiral of basic drugs is commonly carried out in low pH buffer which contributes to strong ionic interaction of the cationic drug ions with negatively charged chiral selectors. The two phenomena results in poor enantioseparations. To overcome the problems associated with chiral separations of basic drugs by CE, the effect of guanidine [GU] on the improvement of chiral separation of a model basic drug, fluoxetine [FLX], was investigated. In the present study, GU was used as a cationic additive to the running buffer containing a chiral selector, sulfated beta cyclodextrine. Better results obtained with GU as the buffer additive in enantioseparation of FLX

Analysis of aflatoxin B1 in Iranian foods using HPLC and a monolithic column and estimation of its dietary intake

A high performance liquid chromatographic method was developed for determination of aflatoxin B1 [AFB1] in foods using a monolithic column with sample clean up on an immunoaffinity column. The method was validated for analysis of AFB1 in rice, bread, puffed corn snack, wheat flour and peanut samples. The average recoveries for AFB1 in different foods ranged from 94.4 to 102.5% with the coefficient of variation lower than 10% for all foods. Limit of detection was 0.01 ng/g. A survey of AFB1 was performed on 90 samples collected from Tehran retail market in June 2005. The results showed that none of the bread and wheat flour samples were contaminated with AFB1. The mean AFB1 levels in rice, puffed corn snack and peanut samples were 4.17, 0.11, and 1.97 ng/g, respectively. The level of contamination of 3 samples [one rice sample and two peanuts samples] to AFB1 was found to be higher than 5 ng/g. Although all food samples had mean concentration of AFB1 below the maximum tolerated level in Iran, the mean intake of AFB1 from rice was estimated 3.49 times higher than the guidance value of 1 ng AFB1/Kg body weight/day. Therefore, it is strongly recommended to monitor AFB1 in foods, especially in rice, in Iran. This is the first study on exposure assessment of Iranian population to AFB1

Evaluation of anti-nociceptive and anti-inflammatory activities of novel chalcone derivatives

Chalcone [1, 3-diarylprop-2-en-1-one] derivatives have been introduced as selective cyclooxygenase-2 inhibitors. In the present study, anti-nociceptive and anti-inflammatory effects of eight novel compounds were evaluated in male mice and Wistar rats by using the writhing and formalin-induced paw edema tests respectively. The activities of the compounds were compared with celecoxib as a reference drug. Then, novel compounds were divided into two regioisomeric groups based on the position of the methyl sulfonyl substitution. Compounds with substituents such as: 1] H, 2] Me, 3] F and 4] Cl at para position of the phenyl ring of [E]-3-[4-Methanesulfonylphenyl]-1-phenylprop-2-en-1-one were selected in the first group. The regioisomer compounds with 5] H, 6] Me, 7] F and 8] OMe substitutions at C-4 of phenyl ring of [E]-1-[4-Methanesulfonylphenyl]-3-phenylprop-2-en-1-one were chosen as second group. All compounds showed dose-dependent anti-nociceptive activity in writhing test. Interestingly, the potency of anti-nociceptive effect of compounds 1, 2, 5 and 6 were significantly higher than celecoxib. The regioisomeric compounds 1 and 5 with high anti-nociceptive effects, showed a significant dose-dependent anti-inflammatory activity in the paw edema test as well. The results showed that compounds with no substituent or small size substituents at para position of the phenyl ring are the most potent compound in writhing test. Our results revealed that the introduction of a bulky group such as methoxy or chlorine at the vicinal aromatic chain of the derivatives decreases the anti-inflammatory/anti-nociceptive effects. The comparison of estimated ED[50] of each pair of the regioisomeric compounds indicates that the relative position of SO[2]Me to carbonyl moiety did not affect the potency

Physical and chemical stability of mycophenolate mofetil [MMF] suspension prepared at the hospital

To evaluate the physical and chemical stability of a suspension of mycophenolate mofetil [MMF] prepared in the hospital from commercially available MMF capsules and tablets. Extemporaneous pharmacy was used as a feasible method in this experimental study to prepare suspension form of MMF. Suspension formulations were prepared from both tablets and capsules forms of MMF. Thereafter the stability parameters such as pH, microbial control, thermal and physical stability and particle sizes were evaluated. The amount of MMF, in the suspension was measured at various time points by HPLC. The HPLC method showed that concentration of suspensions prepared from tablets and capsules were 49 mg/mL and 50 mg/mL at time 0, respectively. The effective amount of suspensions prepared from capsules was 101% at time 0, 100% after 7 days, 98% after 14 days, and less than 70% after 28 days. According to the obtained results in this study, capsule-based suspension was stable for as long as 14 days at 5°C. This formulation appears to be clinically acceptable and provides a convenient dosage form for pediatric patients and for adults during the early postoperative period

Exposure assessment of the Tehran population [Iran] to zearalenone mycotoxin

Zearalenone [ZEA] mycotoxin is a potent estrogenic metabolite. It is the primary toxin causing infertility, abortion or other breeding problems. A HPLC method was validated for ZEA in foods using a monolithic column with sample clean-up on an immunoaffinity column. A certified reference material [CRM] from FAPAS [UK] was analyzed. A survey of ZEA was performed on the 72 samples of rice, bread, puffed corn snack and wheat flour collected from Tehran retail market. The average recovery and coefficient of variation in different foods ranged 92.7-107.1 and 4.9-13.8%, respectively. The amount of ZEA in corn CRM was in the acceptable range of FAPAS. The limit of quantification was 3 ng/g for rice, bread and wheat flour and 2.7 ng/g for puffed corn snack. The retention time of zearalenone was 2.6 min. All samples had contamination level lower than the maximum tolerated level of ZEA in foods in Iran. The mean intake of ZEA from all samples was much lower than the tolerable daily intake estimated by JECFA. This is the first survey on ZEA contamination in bread and rice in Iran as well as the first study on exposure assessment of Tehran population to ZEA

pharmacological effects of odonthobuthus doriae scorpion venom and its extracted fractions on neuro-muscular transmission

The effect of Odonthobuthos doriae [O.d] scorpion venom at 0/3, 1 and 3, 10 microg/ml concentrations were investigated on nerve-muscle transmission, using the Twitch tension technique. A concentration of 0.3 microg/ml caused a small change in the twitch height in response to indirect muscle stimulation, but higher concentrations [1, 3, 10 microg/ml] caused a transient augmentation in twitch response followed by a large contracture in the chick biventer cervices [CBC] preparation. This effect could be defined as a complex action of the venom, predominately presynaptic, in which its' effects on postjunctional synapses is also maintained. In order to find out which bioactive fraction could explain the venom effects, the soluble crude venom was partially separated by the gel filtration method, using a Sephadex G50 column, and four fractions were separated. Two of the four purified fractions [O.d F[3], O.d F[4]] were characterized as toxic and their LD[50] values were lower than the crude venom. Unlike the O.d Fj and O.d F[2] fractions, O.d F[3] and O.d F[4] fractions caused a significant block in the twitch and contracture, in comparison to the control sample. in conclusion, fractions O.d F[3] and O.d F[4] are supposed to be as the biological active components of the O.d. venom

Design and synthesis of new imidazole derivatives of captopril

A new series of alkylthio imidazole analogues of captopril, an ACE inhibitor used in the treatment of hypertension, was designed and synthesized in order to obtain agents more active than captopril with less side effects. All the compounds thus prepared were purified and characterized by IR, NMR and Mass analytical instruments

Survey of fumonisin B1 contamination of corn in northern Iran during 2000

Fumonisin B1 [FB1] is the most abundant of the fumonisin mycotoxins, mainly produced in corn by fungi of the genus Fusarium. FB1 has been shown to be hepatocarcinogenic and nephrocarcinogenic in animals. Contamination of corn with FB1 was assayed in samples collected from Mazandaran Province, situated on the Caspian littoral of Iran, in September 2000. In this survey, 38 corn samples were analyzed using HPLC, and all except one showed high levels of FB1 contamination ranged between 1.19 and 12.95 mg/kg. These results confirm the relatively high levels of FB1 contamination in corn of Mazandaran Province

Separation of somatropin and its degradation products by high-performance liquid chromatography using a reversed-phase polymeric column

The accurate prediction of protein stability is one of the most challenging goals in protein formulation and delivery. In this study, a gradient RP-HPLC method is described for the separation of human growth hormone [hGH] variants as deamidated and oxidized forms. The methodology employed a polymeric poly [styrene-co-divinylbenzene] column and a 1mL/min flow rate of a linear gradient of 0.1% v/v TFA/acetonitrile and TFA/Water [pH=2.0] mixture as the mobile phase. The overall run time of this method was 12 min and the average retention times were about 8.7 min for the native somatropin, 7.2 min for the deamidated form and 1.6 and 5.3 min for oxidized variants. The method was also validated in terms of selectivity, linearity, intra- and inter-day variations. In conclusion the method was found to have the potential for being applied as an initial and rapid evaluation method for assessing the quality and quantity of hGH during downstream processing, formulation and storage