VALSTAT program has been developed using C++ in order to perform quantitative structure activity relationship analysis using stepwise multiple regression analysis. It is attempted to design and write program to select the better model for regression analysis and various quantitative structure activity relationship analysis validation methods such as cross-validation, boot strapping, randomization test, outliers, which are not available in the PC-based quantitative structure activity relationship analysis softwares. The program reproducibility and accuracy was validated using few reported series of cyclooxygenase-2 inhibitors.

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Hydrogels are presently under investigation as a delivery system for bioactive molecules, because of their similar physical properties as that of living tissue, which is due to their high water content, soft and rubbery consistency, and low interfacial tension with water or biological fluids. Anionic hydrogels are used in the design of intelligent controlled release devices for site-specific drug delivery of therapeutic proteins to the large intestine, where the biological activity of the proteins are prolonged, and cationic hydrogels are studied for the development of self-regulated insulin delivery system, which releases the insulin in response to changing glucose concentration. The different methods of preparation of hydrogels, novel methods of crosslinking used in the preparation of hydrogels, the mechanism of water transport through the ionic hydrogels, and the release mechanism of the solute from the hydrogels, are discussed in the present article.

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A series of 2-Substituted (1,3,4) thiadiazolo quinazolines were synthesized by the cyclocondensation of 3-amino-2-mercapto quinazolin-4(3H)-ones with various one-carbon donors and screened for their CNS activities (analgesic, anti-inflammatory, sedative-hypnotic and anticonvulsant). Compound III showed good CNS depressant activity, and it is comparable with the reference standard diazepam. While all the test compounds offered significant protection against strychnine-induced and hypoxic induced convulsion, compound III exhibited equivalent activity with the standard diazepam at the dose tested, and it was found to be significant when compared to control.

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In the present investigation, an attempt has been made to increase therapeutic efficacy, reduce frequency of administration, and improve patient compliance, by developing sustained release matrix tablets of diclofenac sodium. Sustained release matrix tablets of diclofenac sodium, were developed by using different drug: polymer ratios, such as F1 (1:0.12), F2 (1:0.16), F3 (1:0.20), F4 (1:0.24) and F5 (1:0.28). Xanthan gum was used as matrix former, and microcrystalline cellulose as diluent. All the lubricated formulations were compressed using 8 mm flat faced punches. Compressed tablets were evaluated for uniformity of weight, content of active ingredient, friability, hardness, thickness, in vitro dissolution using basket method, and swelling index. All the formulations showed compliance with pharmacopoeial standards. Among different formulations, F1 showed sustained release of drug for 12 hours with 89.67% release. The effect of other parameters like addition of release modifier (PEG 6000), gum concentration, pH of dissolution medium, rotation speed and dissolution by paddle method, were also studied. Selected formulation (F1) was subjected to stability studies for three months at 0-4°, room temperature (28°), and 45° with RH 75±5%, and showed stability with respect to release pattern. The kinetic treatment showed that the release of drug follows zero order kinetic (R ² = 0.9758). Korsmeyer and Peppas equation gave value of n = 0.9409 which was close to one, indicating that the drug was released by zero order kinetic. Thus, Xanthan gum can be used as an effective matrix former, to extend the release of diclofenac sodium.

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This study concerns the evaluation of natural gum copal and gum damar as novel sustained release matrix forming materials in tablet formulation. Along with the physicochemical properties, gum copal and gum damar were characterized for molecular weight, polydispersity index and glass transition temperature. Matrix tablets were prepared by wet granulation technique using isopropyl alcohol as a granulating agent. Diclofenac sodium was used as a model drug. Tablet weight (250 mg) and diameter (9 mm) was kept constant. Tablets were evaluated for pharmacotechnical properties, drug content uniformity and in vitro drug release kinetics. Effect of gum concentration (10, 20 and 30% w/w with respect to total tablet weight) on in vitro drug release profile was examined. Both the gums produced matrix tablets with good strength and acceptable pharmacotechnical properties. Matrix tablets with 30% w/w gum copal and gum damar showed sustained drug delivery beyond 10 h. Drug release from gum copal matrix tablets followed zero order kinetics while gum damar (10 and 20% w/w) was found suitable to formulate the insoluble plastic matrix that releases the drug by diffusion. It is concluded that both gums possess substantial matrix forming property that could be used for sustained drug delivery.

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Ultraviolet absorption spectrophotometric method for the estimation of poorly water soluble drugs like nalidixic acid, norfloxacin, tinidazole, and metronidazole in pharmaceutical formulations, has been developed. Aqueous solubilities of these selected model drugs were enhanced to a great extent (5 to 98 fold) in 2.0 M sodium benzoate, and in 2.0 M niacinamide solutions. The primary objective of the present investigation was to employ these hydrotropic solutions to extract the drugs from their dosage forms, precluding the use of costlier organic solvents. The selected lmax for nalidixic acid, norfloxacin, tinidazole, and metronidazole, were 330 nm, 324 nm, 318 nm and 320 nm, respectively. Sodium benzoate and niacinamide did not show any absorbance above 300 nm, and therefore, no interference in the estimation was seen. The results of analysis have been validated statistically, and by recovery studies. The proposed methods are new, simple, economic, accurate, safe, and precise.

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A simple, precise, accurate, and rapid HPLC method has been developed, and validated for the determination of atorvastatin and amlodipine simultaneously, in combined tablet dosage form. The mobile phase used was a mixture of acetonitrile and 0.03M phosphate buffer pH 2.9 (55:45% v/v). The detection of atorvastatin and amlodipine was carried out on dual g absorbance detector at 240 nm and 362 nm, respectively. Results of the analysis were validated statistically, and by recovery studies. The proposed method can be successfully used to determine the drug contents of marketed formulation.

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There has been keen interest in the development of a novel drug delivery system. Novel drug delivery system aims to deliver the drug at a rate directed by the needs of the body during the period of treatment, and channel the active entity to the site of action. At present, no available drug delivery system behaves ideally achieving all the lofty goals, but sincere attempts have been made to achieve them through novel approaches in drug delivery. A number of novel drug delivery systems have emerged encompassing various routes of administration, to achieve controlled and targeted drug delivery. Encapsulation of the drug in vesicular structures is one such system, which can be predicted to prolong the existence of the drug in systemic circulation, and reduce the toxicity, if selective uptake can be achieved. Consequently a number of vesicular drug delivery systems such as liposomes, niosomes, transfersomes, and pharmacosomes were developed. Advances have since been made in the area of vesicular drug delivery, leading to the development of systems that allow drug targeting, and the sustained or controlled release of conventional medicines. The focus of this review is to bring out the application, advantages, and drawbacks of vesicular systems.

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Monolithic matrix tablets of ambroxol hydrochloride were formulated as sustained release tablets employing hydroxypropyl methylcellulose polymer, and the sustained release behaviour of the fabricated tablets was investigated. Sustained release matrix tablets containing 75 mg ambroxol hydrochloride were developed using different drug polymer ratios of hydroxypropyl methylcellulose. Tablets were prepared by direct compression. Formulation was optimized on the basis of acceptable tablet properties and in vitro drug release. The resulting formulation produced robust tablets with optimum hardness, consistent weight uniformity and low friability. All tablets but one exhibited gradual and near-completion sustained release for ambroxol hydrochloride, and 98-101% released at the end of 12 h. The results of dissolution studies indicated that formulation F-V (drug to polymer 1:1.47), the most successful of the study, exhibited drug release pattern very close to theoretical release profile. A decrease in release kinetics of the drug was observed on increasing polymer ratio. Applying exponential equation, all the formulation tablets (except F-V) showed diffusion-dominated drug release. The mechanism of drug release from F-V was diffusion coupled with erosion (anomalous).

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The small and simple benzothiazole nucleus is present in compounds involved in research aimed at evaluating new products that possess interesting biological activities, such as antitumor, antimicrobial, anthelmintic, antileishmanial, anticonvulsant and antiinflammatory. The present review focuses on the benzothiazoles with potential activities that are now in development.

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Two simple, rapid, accurate and economical methods have been developed for the estimation of gatifloxacin and ornidazole in the mixture. Gatifloxacin has absorbance maxima at 286.2 nm and ornidazole has absorbance maxima at 319 nm in distilled water. The linearity was observed in the concentration range of 2-14 μg/ml for gatifloxacin and 2-20 μg/ml for ornidazole. First method is based on the simultaneous equations and second method is based on Q-absorbance ratio. Absorbances at isoabsorptive point 299.2nm and at the λ-max of ornidazole. These methods were validated statistically. The recovery studies confirmed the accuracy of the proposed methods.

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A simple, precise, accurate and rapid high-performance thin-layer chromatographic method has been developed and validated for the estimation of atorvastatin calcium and ezetimibe simultaneously in combined dosage forms. The stationary phase used was precoated silica gel 60F ₂₅₄ . The mobile phase used was a mixture of chloroform: benzene: methanol: acetic acid (6.0:3.0:1.0:0.1 v/v/v/v). The detection of spots was carried out at 250 nm. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found to be linear between 0.8 and 4.0 µg/spot for atorvastatin calcium and 0.1 and 1.0 µg/spot for ezetimibe. The limit of detection and the limit of quantification for atorvastatin calcium were found to be 170 ng/spot and 570 ng/spot respectively, and for ezetimibe, 20 ng/spot and 70 ng/spot respectively. The proposed method can be successfully used to determine the drug content of marketed formulation.

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Many plants used in Saurashtra folk medicine have been reported to exhibit high antibacterial and antioxidant activities. In the present study, some parts of five plants, Guazuma ulmifolia L., Manilkara zapota L., Melia azedarach L., Syzygium cumini L. and Wrightia tomentosa R.& S., were evaluated for their antibacterial activity, total phenol content, flavonoid content, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity and phytochemical analysis, using successive extraction by cold percolation method with petroleum ether, ethyl acetate, methanol and water. In vitro antibacterial activity was evaluated against five bacterial strains viz. Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhimurium and Enterobacter aerogenes by agar well diffusion method. Among the plants screened, W. tomentosa leaf and fruit showed the best antibacterial activity. The Gram-positive bacteria were more susceptible than Gram-negative bacteria. Methanol extract of M. zapota showed the best 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity. Highest total phenol content was shown by M. zapota and S. cumini in methanol extract, while highest flavonoid content was shown by W. tomentosa stem in petroleum ether extract and ethyl acetate extract. In all the plants, cardiac glycosides and triterpenes were more as compared to other phytoconstituents.

[ABSTRACT]  [FULL TEXT]  [PDF] [CITATIONS]  [PubMed]

Recently, fast-dissolving drug delivery systems have started gaining popularity and acceptance as new drug delivery systems, because they are easy to administer and lead to better patient compliance. Usually, elderly people experience difficulty in swallowing the conventional dosage forms (tablets, capsules, solutions and suspensions) because of tremors of extremities and dysphagia. Fast dissolving drug delivery systems may offer a solution for these problems. Fast dissolving drug delivery can be achieved by various techniques like direct compression, wet granulation, compression moulding, volatilization and freeze-drying. They involve different mechanisms like use of high amounts of hydrophilic disintegrating agents of effervescent combinations, which allow the dosage forms to disintegrate quickly in the patient's mouth on contact with saliva. There are more than fifteen fast-dissolving products in the market worldwide.

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Ethanol extract of Piper longum fruits and five different crude fractions, petroleum ether (40-60°), solvent ether, ethyl acetate, butanol and butanone were subjected to preliminary qualitative chemical investigations. The ethanolic extract and all other fractions were screened orally for hepatoprotective activity in adult Wistar rats. The ethanolic extract and butanol fraction have shown significant activity, lowering the serum enzymes glutamic oxaloacetic transaminase and glutamic pyruvic transaminase in rats treated with carbon tetrachloride when compared to control and Liv-52-treated rats.

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Zidovudine is a potent antiviral agent acting on acquired immunodeficiency virus. Orally administered zidovudine, however has strong side effects. Therefore an adequate zero order delivery of zidovudine is desired to maintain expected anti-AIDS effect. In the present study we encapsulated the zidovudine, in recently developed novel vesicular carrier ethosomes, for its enhanced transdermal delivery and results were compared with liposomes. Ethosomes of zidovudine were prepared and characterized in vitro and in vivo. The effect of different formulation variables on skin permeation of zidovudine was studied using locally fabricated Keshry-Chien type of diffusion cell. To understand the mechanism of better skin permeation of ethosomes, vesicle skin interaction study was carried out. To confirm the better skin permeability of ethosomes, fluorescence microscopy using rhodamine 123 as fluorescence probe was performed. Results were compared with those obtained after administration of liposomes and hydroethanolic and ethanolic solution of drug. The optimized ethosomal formulation showed transdermal flux 78.5±2.5 μg/cm2/h across the rat skin as compared to 5.2±0.5μg/cm2/h for control hydroethanolic solution of drug, and 7.2±0.6 μg/cm2/h for ethanolic drug solution. Vesicle skin interaction study showed that ethosomes affected the ultrastructure of the stratum corneum, distinct regions with lamellar stacks derived from the vesicle were observed in intercellular spaces of the stratum corneum. These lamellar stacks disrupted the organization of the skin bilayers leading to increased skin permeability. This was further confirmed by fluorescence microscopy. Finally, it can be concluded from the study that complex lipid molecule, ethosomes can increase the transdermal flux, prolong the release and present an attractive route for the sustained delivery of zidovudine. Our results indicate that the ethosomal system may be a promising candidate for transdermal delivery of number of problematic drug molecules.

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In the present study, a novel series of 2-methyl-qninazolin-4(3H)-ones were synthesized and characterized by IR, 1H-NhlR, 13C-NMR and mass spectral analysis. The synthesized compounds were screened for analgesic (100, 200 and 400 mg/kg), antiinflammatory (200 and 400 mg/kg), antibacterial (Bacillus subtilis, Bacillus cereus, Staphylococcus epidermidis, Micrococcus Iufeus and Escherichia coli) and antifungal (Candida albicans and Aspergillus niger) activities. The minimum inhibitory concentrations of the compounds were also ascertained by agar dilution method. Graded dose response was observed with the compounds. 6,8-dibromo-2-methyl-3-(4'-morpholino-phenyl)- 4(3H)-one (2) exhibited the highest analgesic and antiinflammatory activity. 6-Bromo-2-methyl- 3-(4'-morpholino-phenyl)-quinazolin-4-(3H)-one (1) was found to exhibit the highest antimicrobial activity. All the compounds exhibited significant activity against the bacteria and fungi tested.

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Ethyl cellulose microspheres of glipizide were prepared by an industrially feasible emulsion-solvent evaporation technique and the microspheres were investigated. The microspheres are spherical, discrete and free-flowing. Encapsulation efficiency was in the range of 81-91%. Glipizide release from the microspheres was slow and diffusion controlled and extended over a period of 10 d and depended on core:coat ratio, wall thickness and size of the microspheres. Good linear relationships were observed between percent coat, wall thickness and release rate of the microspheres. In the in vivo, the microspheres produced a sustained hypoglycemic effect over 6 d in normal rabbits. These microspheres were found suitable for parenteral controlled release.

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A simple, sensitive HPTLC method was developed for the analysis of atorvastatin calcium in its commercial single component tablet formulations (10 mg/tablet). The stationary phase was precoated silica gel 60 F254. The mobile phase used was a mixture of benzene: methanol, (7:3 v/v). Combination of benzene: methanol offered optimum migration (RF=0.46±0.02). Detection of the spots was carried out at 281 nm. The method was validated in terms of linearity (200-600 ng/spots), precision (intra-day variation: 0.25 to 1.01%, inter-day variation: 0.21 to 0.88%), accuracy (99.2±0.48) and specificity. The limit of detection and limit of quantification for atorvastatin calcium were found to be 40 ng/spot and 200 ng/spot, respectively. The proposed method was successfully applied to determine atorvastatin calcium content of 10 individual tablet units o f two market formulations, after extracting atorvastatin calcium with methanol. Both the formulation complied with the USP specifications (RSD less than or equal to 6 %) of the content uniformity test. The proposed HPTLC method can analyse ten or formulation units simultaneously on a single plate and provides a faster and cost-effective quality control tool for routine analysis of atorvastatin calcium tablet formulation.

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Three simple and sensitive spectrophotometric methods (I, II, and III) in the visible region have been developed for the quantitative estimation of nitazoxanide in bulk drug and pharmaceutical formulations. These methods are based on the reaction of reduced nitazoxanide with p-dimethylaminobenzaldehyde, p-dimethylaminocinnamaldehyde and vanillin in acidic conditions to form pink, orange red, and orange yellow coloured chromogens with absorption maxima at 559 nm, 534.5 nm, and 475 nm respectively. The reduction of nitazoxanide was carried out with zinc granules and 5 N hydrochloric acid at room temperature in methanol. Beer's law is obeyed in the concentration range of 5-25 mg/ml, 5-25 mg/ml, and 10-50 mg/ml respectively. The results of analysis have been validated statistically and by recovery studies. The methods were found to be accurate, precise, rapid, and economic. The results are comparable with those obtained with visible spectrophotometric method in methanol at 402 nm.

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Fast dissolving tablets of diclofenac sodium were prepared using direct compression after incorporating superdisintegrants such as cross linked carboxymethylcellulose, sodium starch glycolate and cross linked povidone in different concentrations. All the formulations were evaluated for the influence of disintegrants and their concentrations on the characteristics of fast dissolving tablet mainly in terms of disintegration time and dissolution rate. Tablets containing cross-linked carboxymethylcellulose showed better disintegrating character along with rapid release (90% drug release in 10 min.). No appreciable difference was found between the formulations containing other two superdisintegrants. The concentration of the superdisintegrants had also an effect on disintegration time and in vitro dissolution. There seems to be a trend towards use of higher level of disintegrants producing rapid disintegration and faster dissolution. The resulting tablets were also evaluated for its hardness and friability and were found to be independent of disintegrant concentration.

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Naphtho[2,1-b]furyl-2-carboxyhydrazide 1 has been condensed with various substituted acetophenones to obtain corresponding carboxy hydrazones 2, which on treatment with Vilsmeier-Haack reagent resulted in the formation of 2-[3-phenyl-4-formyl -1-carbonyl]naphtho[2,1-blfuran pyrazole derivatives 3a-f. The compound 1 has been converted into N-aroyl-N'-(naphtho[2,1-b]furan- 2-carbonyl)hydrazine 4a-c, which on cyclization with phosphorous oxychloride produced 2-[5- aroyl-1,3,4-oxadiazol-2-yl]naphtho[2,1-b]furans 5a-c. The compound 6 has been synthesized by the condensation of 1 with ethyl acetoacetate. Various naphtho[2,1-b]furan-2-[N'-(substituted benzopyran-2'-one-3'-carbonyl)]hydrazides 8a-d, have been prepared from compound 1 via compound 7.The compounds 8a-d have also been synthesized by direct condensation of 1 with 6- substituted coumarins. All newly synthesized compounds have been characterized by elemental analysis and spectral data and screened for antimicrobial, anthelmintic, antiinflammatory, analgesic and diuretic activities.

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Learning is a continual process and our brain keeps track of events taking place in our lives, consciously or subconsciously. The capacities of learning, understanding and memory are all crucial for one's growth. Scientists are trying their level best to find out the root cause of Alzheimer's disease. We have endeavored to throw light on neurochemical mechanisms of learning and memory. The implication of cholinergic system, adrenergic system, dopaminergic system, serotonergic system, GABA-ergic system, benzodiazepine-receptors, NMDA, neuropeptides, histamine, insulin, estrogens, nitric oxide, oxygen free-radicals and platelet activating factor have all been discussed in the updated review article. Future drugs and new strategies for prevention of Alzheimer's disease have also been incorporated at the end.

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The title compounds 2-mercapto-3-(substitutedmethylamino) quinazolin-4(3H)-ones were synthesized by condensing the active hydrogen atom of 3-amino group of 3-amino-2-mercapto quinazolin- 4(3H)-one with formaldehyde and the desired amines. Investigation of antimicrobial activity of the compounds was performed by agar dilution method against 6 pathogenic bacteria, 3 pathogenic fungi and antiHlV activity against replication of HIV-1 (IIIB) and HIV-2 (ROD) in MT-4 cells. The compounds exhibited significant antibacterial and antifungal activities.

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Mucoadhesive chitosan microspheres of amlodipine besylate were prepared for nasal administration with the aim of avoiding the first pass effect. A series of batches of microspheres were prepared by simple emulsification crosslinking method to optimize parameters like external phase (mixture of heavy and light liquid paraffin in the ratio of 1:1), stirring rate (1200 rpm), dioctyl sodium sulfosuccinate concentration (0.2% w/v), Chitosan:drug ratio (2:1), volume of crosslinking agent (glutaraldehyde, 1 ml) and time of crosslinking (3 h). The microspheres were evaluated for physical characteristics such as particle size, particle shape and surface morphology by scanning electron microscopy, drug entrapment efficiency, in vitro mucoadhesion, and in vitro drug release characteristics. The microspheres had a mean particle size of 36.47 + 3.39 mm, suitable for nasal administration. Electron microscopy revealed that microspheres were spherical with nearly smooth surface morphology. Application of in vitro drug release data to various kinetic equations indicated matrix diffusion controlled drug release from chitosan microspheres.

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