Modified guar gum was used as a matrixing agent to develop sustained-release tablets of diltiazem hydrochloride. Modified guar gum was a combination of guar gum and lactic, citric, or tartaric acid. The lactic acid modified guar gum exhibited improved swelling characteristics at pH 1.2 and 7 as compared to that of the untreated guar gum. Seven formulations were prepared according to the simplex lattice design. The amount of modified guar gum, untreated guar gum, and dicalcium phosphate dihydrate were chosen as independent variables. The time required for 80% drug dissolution (t80) in distilled water was selected as the dependent variable and a response equation with interaction terms was generated. A mathematical model was evolved to describe the dissolution profile using log time as an additional independent variable. The kinetics of drug release is explained by Korsemeyer and Peppas model.

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Different topical formulations containing ciprofloxacin and tinidazole in lanolin petrolatum base, emulsion (water washable) base and PEG (water soluble) base were prepared and evaluated for drug release in phosphate buffer (pH 6.0). Antimicrobial activity of these formulations were compared against marked formulation containing 1% w/w silver sulfadiazine USP. It was found that release of ciprofloxacin and tinidazole from the PEG base was maximum through sigma membrane in phosphate buffer (pH 6.0) and also observed that the release of tinidazole was more than that of ciprofloxacin. The formulations exhibited significant antimicrobial activity both against aerobic and anaerobic bacteria compared to the marketed formulation. The antimicrobial activity of formulation containing PEG was found to be higher than other formulations.

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A simple spectrophotometric method in visible region is described for estimation of amlodipine besylate and benidipine hydrochloride from their respective tablet formulations. The developed method is based on formulation of coloured chloroform extractable complex of drug with rhodizonic acid. Extracted complex of amlodipine besylate showed absorbance maxima at 450 nm while complex of benidipine hydrochloride showed absorbance maxima at 497.5 nm. Beer’s law is obeyed in the concentration range of (0.1-1.5 mg/ml) for both the drugs. Results of analysis were validated statistically and by recovery studies.

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Mechanism of interaction of metronidazole with bovine serum albumin has been reported. Association constant for drug -protein binding showed that the interactions are non-covalent in nature and there are two independent binding sites. The reaction was found to be first order with rate constant 1.832 S-1 and activation energy 13.194 KJ mol-1. The drug does not compete with hydrophobic probe, 8-anilino-1-naphthalene sulphonic acid sodium salt (ANS) for hydrophobic sites on the surface. The decrease in critical micellar concentration (CMC) of cationic surfactant, cetyltrimethylammonium bromide (CTAB) in the presence of metronidazole showed that the drug does not have predominantly hydrophobic character and is not solubilized inside the micelle. Reduction in surface tension of the solvent suggested that the drug has a weakly hydrophobic character. Stern-Volmer analysis of fluorescence quenching data showed that both tryptophan residues of BSA are involved in the drug-protein interaction. The high magnitude of the rate constant for quenching, kq, (1013M-1S-1) could be attributed to increase in the encounter radii of tryptophan-metronidazole due to hydrogen bonding interaction between BSA and drug. Thermodynamic parameters, obtained from data at different temperatures, showed that the binding of metronidazole to BSA involves the formation of both hydrogen and hydrophobic bonds. However, much smaller magnitude of ΔS° value showed that the hydrogen bond formation interaction predominates.

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Chemical investigation of Hygrophila spinosa root exhibited the presence of a greasy mass, lupeol and lupenone in petroleum ether extract. Crude petroleum ether extract, when administered (i.p) to mice, potentiated the sedative-hypnotic action of chlorpromazine, diazepam, pentobarbitone, chlordiazepoxide and protected against strychine-induced convulsions.

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N-hydroxy methyl derivative of 2(4-isobutyl phenyl) propionamide was synthesised and condensed with seven different active hydrogen containing compounds (antipyrine, pyrrolidine, piperidine, phthalimide, morpholine, piperazine and hydrazine). These compounds were characterised by their analytical and spectral data. The antiinflammatory activity of the synthesised compounds was evaluated by carrageenan-induced rat paw oedema method and the compounds with pyrrolidine, phthalimide and hydrazine showed potent antiinflammatory activity.

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Immunization against infectious diseases has saved innumerable lives and contributed to today's increased life expectancy. In spite of these impressive results, there is still considerable potential for improved vaccines. New strategies to achieve safe and effective immunization are under investigation. Many vaccination guidelines call for multiple dosing schedules. Reduction of injection frequency, by having controlled release, peroral or nasal vaccine delivery systems could lead to better immunological protection of the population and might facilitate in eradication of some infectious pathogens. Some aspects of safety are closely related to the route of administration, such as granuloma formation or allergic reaction at the injection site and storage conditions. Serious failures of smallpox and measles immunizations have resulted from inadequate refrigeration. New vaccine delivery systems have shown to possess greater effectiveness, improved adjuvanticity, in vitro and in vivo stabilization of antigens, safety from risk of infections and side effects. Furthermore, results obtained by delivering the new subunit vaccines against diseases such as Hepatitis B, HIV, malaria by novel delivery systems have shown encouraging results. Biodegradable micropheres made up of PLGA, liposomes, nanoparticles, immunostimulating complexes and nonionic surfactant vesicles have been reviewed here and these have found to be promising modes of vaccine delivery.

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A series of (Z)-4,5-dihydro-4-[(substituted phenyl)methylene]-5-oxo-2-phenyl-1H-imidazole-1-acetic acids (1-11) and a few of (Z)-4,5-dihydro-4-[(substituted phenyl)methylene]-2-methyl-5-oxo-1H-imidazole-1- acetic acids (12-14) were synthesized and evaluated for antiinflammatory activity. Ten compounds showed significant antiinflammatory activity. Compound 2 exhibited activity comparable to phenylbutazone. It also showed significant antiarthritic activity and was less ulcerogenic than phenylbutazone. Five compounds exhibited significant analgesic activity. Several compounds showed good activity in scavenging the stable free radical DPPH. QSAR studies suggested that none of the physicochemical parameters studied showed good correlation to the antiinflammatory activity.

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Previously, a series of 21 N10-substituted phenoxazines were examined for reversing vinca alkaloid resistance against MDR KBChR-8-5 and GC3/cl cells. Within the series, there are compounds that inhibit efflux (verapamil-like activity), whereas others markedly increased vinca alkaloid accumulation without having detectable inhibitory activity of the efflux component. It has been shown that MDR modulators that inhibit photoaffinity labeling of P-gp were generally the most potent MDR reversers. To show whether this observation is true, P-gp rich membrane fractions from KB-V1 cells were isolated and the interaction of [3H] azidopine with membrane fractions in the presence of 25, 50 and 100 mM concentration of each of the twenty N10 -substituted phenoxazines was undertaken and the extent of competition was compared to a standard modulator, verapamil. Examination of the competition data showed that only two modulators 4 and 6 exhibited the maximum competition (>50%) and the remaining modulators were found to exhibit the inhibition of the photolabeling by less than 45%. However, modulators 12, 14 and 19 failed to compete for azidopine 1abeling. Within the series of compounds examined, the competition of phenoxazines for [3H] azidopine binding to P-gp follows the order: propyl>butyl>acetyl series. It has been found that, from among the compounds examined, three of them interact strongly (>50%), six marginally (<45%) and remaining failed to interact with P-gp, indicating that there may be multiple mechanisms for MDR.

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Three copolymers of methacrylic acid and 2-ethylhexyl acrylate in the ratios 30:70, 40:60, and 50:50 were synthesized by emulsion polymerization technique in our laboratory. The following acute toxicity and biological reactivity tests were carried out on these polymers : (a) Systemic Injection Test, (b) Intracutaneous Test, (c) Dermal Irritation Test, (d) Implantation Test, (e) RBC Haemolysis Test, (f) Agar Diffusion Test, (g) Direct Contact Test and (h) Elution Test. The results revealed that the copolymers are devoid of any acute toxicity and biological reactivity.

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The transdermal films of terbutaline sulphate were formulated using the hydroxy propyl methyl cellulose for achieving controlled release of the drug for the treatment of asthma. The films were subjected to in vitro diffusion studies using a static diffusion cell of Keshary-Chein type at two different temperatures such as 37° and 40° to observe the effect of the temperature on the diffusion of the drug and to calculate the molar enthalpy of diffusion. The drug release increased with increasing temperature. It appears that the process being endothermic, it can be spontaneous only if it proceeds towards maximum randomness. Therefore, the entropy change associated with changes in the state and free energy were determined.

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A simple, fast and precise extractive spectrophotometric method for estimation of fluoxetine hydrochloride from pharmaceutical formulations has been proposed. It is based on extraction of colored complex formed between fluoxetine hydrochloride and bromothymol blue in chloroform. This yellow complex has an absorption maxima at 412 nm with molar extinction coefficient 13.6 X 103 1 mol-1 cm-1. The system obeys Beer’s law in the range of 1.5-20.0 mg/ml of fluoxetine hydrochloride. The proposed method gave reproducible results for determination of fluoxetine hydrochloride from pharmaceutical formulations.

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HPLC method for the estimation of a new spermicidal and anti HIV agent, 1-(4-methoxy phenyl), 5-piperidino penta-1,4-diene-3-one. Tartarate [CDRI compound 87/132] in bulk samples and formulations is described. The calibration curve was linear in the range of 50-500 mg/ml. This method was used for the estimation of this compound in its formulations.

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A simple and convenient titrimetric method for the determination of sulpha drugs in pure form, at milligram level, is developed using potassium ditelluratocuprate (III) in alkaline medium. The response of the titration is observed to be precisive between 1-10 mg drug sample within ± 0.5%.

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New substituted 2-amino-4-(4-chlorophenyl) thiazole-5-acetic acids (6a-k) and esters (7a-l) were prepared by condensaton of thioureas with methyl 3-bromo-3-(4-chlorobenzoyl) propionate. The compounds showed good anti-inflammatory (55-80%, ibuprofen 85%) and analgesic (40-58%, aspirin 57%) activities.

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The compound N1-3’-acetyl-4’5’-dihydro-2’-furanyl-N4-(6-methoxy, 8-quinolinyl)-1,4-pentane diamine [80/53] (I), an anti-relapse antimalarial compound, is now under phase II clinical trials. It was observed that the compound is less stable in acidic medium. Therefore, the present investigation was taken up to study the effect of b-and g-cyclodextrins on the stability of the above compound. The solution of I as well as its cyclodextrin complexes were prepared in acetate buffers of different pH. The order of reaction and degradation rate constant at 30±2° were computed by least square linear regression. The I : b cyclodextrin (1:2) complex showed the best stability of I.

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