Nicotine is one of the highly toxic and addictive chemicals, belonging to tobacco alkaloids. In the present work, a HPTLC method was developed for the estimation of nicotine in different brands of Gutkha available in local market. Diethyl ether extracts of standard nicotine and the sample solutions were spotted on pre-coated TLC Silica gel G60 F254 plated and developed using chioroform: methanol: ammonia (60:5:1 v/v) as mobile phase. Densitometric scanning was performed at 255 nm. The linearity was found to be in the concentration range of 200-1000 ng/spot with correlation coefficient of 0.996.The method was validated for precision, repeatability and accuracy. Twenty different brands of Gutkha were analysed for the nicotine content and the results were compared with the nicotine content estimated by an UV-Spectrophotometric method. The content of nicotine in different brands of Gutkha was found to be in the range of 0.1 to 0.5% w/w.

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Diclofenac sodium-pectin complexes were prepared by physical mixture and solvent deposition techniques. Microcapsules of drug and drug-pectin complex were prepared by coacervation phase separation method using ethylcellulose as coating material. The stability of the drug in the formulations were confirmed by TLC and IR studies. Different sizes in a batch of dried microcapsules were separated by sieving. Scanning electron microscopy revealed the morphology of microcapsules. In vitro release from complexes and mirocapsules in distilled water and mechanism of drug release are identified. The dissolution rate decreased with an increase in the concentration of pectin and ethylcellulose added in complexes and microcapsules respectively. Dissolution data were fitted into a double log plot equation, a Fickian release (n=0.5) was obtained for all the complexes and microcapsules. The data demonstrates that controlled release formulation of diclofenac sodium can be developed using a combination of two techniques like complexation and microencapsulation. The binding of drug to pectin was investigated using equilibrium dialysis. The binding data were expressed in the form of Scatchard plot, which indicated two classes of binding sites.

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Flurbiprofen appears to be more active as an antiinflammatory agent than other NSAID products and is usually well tolerated. Gels have gained more and more importance because the gel-based formulations are better percutaneously absorbed than creams and ointment bases. Therefore, flurbiprofen gel formulations were made with different polymers like carbopol940 (0.6-1.2%) and hydroxy propyl methyl cellulose (HPMC) (1.0-4.0%) containing various permeation enhancers namely sodium lauryl sulphate (SLS) (0.25-1.0%) and dimethyl sulfoxide (DMSO) (5-20%) at different proportions, having 1% concentration of drug. The formulated gels were evaluated for drug content, pH, viscosity and in vitro release through the Sigma membrane. Its physical stability was evaluated by freeze-thaw cycling. Selected formulations were evaluated for its antiinflammatory activity using the carrageenin-induced paw edema in rats. The physical stability study revealed that the carbopol 940 gels were highly stable and the gels with HPMC were physically unstable. The carbopol with 15% of DMSO showed best in vitro release of flurbiprofen. In vivo study for the selected formulation showed significant (P<0.001) antiinflammatory activity in the carrageenin-induced paw edema in rat.

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The in vitro antibacterial activity of Notonia grandiflora (whole plant) has been investigated against Staphylococcus aureus, Shigella shigae, Salmonella typhi, Escherlchia coli, Pseudomouas aeruginosa and Proteus mirablis. The essential oil of the fresh plant at 1:10 dilution showed good activity against S. aureus, S. shigae and P. mirablis almost comparable to the standard antibiotic used. The hexane extract showed good activity and the alcohol extract showed feeble activity against P. mirablis. Friedelin isolated from the hexane extract of the plant showed activity at 1000 ppm against this organism.

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Terbutaline-loaded conventional suppositories, sustained release matrix suppositories and sustained release two layered suppositories were prepared using Polyethylene glycol 4000, Drug Coat L100 and Drug Coat S100. In vitro characteristics of these suppositories were evaluated. In comparison to conventional suppositories the release of drug from sustained release matrix suppositories was gradual and extended over a period of time. On the other hand two layered suppositories produced an initial quick release followed by extended release of the drug.

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Albumin microspheres containing methotrexate were prepared in the size range of 12.7 to 19.5 mm, by heat stabilization technique at various concentration of drug and different speeds of agitaticn. They were evaluated by scanning electron microscope (SEM). Through the dissolution study on various batches of drug-loaded microspheres, the batch with optimum drug loading and satisfactory release profile was selected as ideal batch (20 mg drug loaded microspheres prepared by using 500 RPM). In vivo evaluation was done on all the batches using albino mice. The ideal batch showed significant enhancement in drug localization particularly in lungs in comparsion with free drug.

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A gum extract from the pods of Abelmoschus esculentus (Ae) was evaluated as granulating agent for sulphaguanidine granules and tablets. The gum was employed at concentrations of 0,2,4 and 6% (w/w) and granules and tablets were prepared by the weight granulation method. Properties of granules and tablets evaluated as a function of the gum concentraion include: loose densities, flow rate and angle of repose, hardness and friability, disintegration time and dissolution profiles. Granules prepared with Ae possessed good flow characteristics and the polymer exhibited higher binding capacity in sulphaguanidine tablets than maize starch and gelatin at equivalent concentrations. The gum could be employed as a granulating agent in normal release sulphaguanidine tablets at concentration levels of 2 and 4% (w/w). Beyond these concentrations, sulphaguanidine tablets with relatively prolonged released profile was obtained.

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Two Simple and sensitive spectrophotometric methods, A and B have been developed for the determination of meloxicam and its dosage forms. Meloxicam forms stable green coloued chromogen with ferric chloride and potassium fericyanide exhibiting maximum absorption at 770 nm (method A) that shows linearity in concentration of 0.25-2.5 μg/ml. In method B, meloxicam forms blue coloured complex on treatment with Folin Ciocalteu reagent, showing maximum absorption at 740 nm. The chromogen obeys Beer's law in the concentration range of 5-15 μg/ml.

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Dissolution of drugs from solid dosage forms is a key parameter during the product development, formulation and through out the product storage. Rifampicin is very stable in the solid state. Rifampicin transforms into rifampin quinone in mildly alkaline solutions and in presence of atmospheric oxygen at room temperature. The main decomposition product of rifampicin in aqueous acidic medium was 3-formyl rifampicin SV. The decomposition of rifampicin in aqueous solution is diminished by the addition of reducing agents such as ascorbic acid and sodium ascorbate. In USP, 0.1 N HCI is an official dissolution medium and the amount of rifampicin was estimated in comparison with a standard solution having a known concentration of rifampicin concomitantly held at the same temperature for the time specified. This is not suitable for studying release kinetics of controlled release formulations. For this reason, stability of rifampicin in different aqueous fluids and buffers of varying pH in the presence of ascorbic acid as reducing agent was studied. The results indicated that rifampicin was more stable in phosphate buffer of pH 7.4 containing 0.02% w/v of ascorbic acid. Drug release studies of commercial products were done by using this medium and they were compared with the official USP method. This medium was found to be more suitable for studying rifampicin controlled release formulations.

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Co-polymeric hydrogel beads of 2-hydroxy ethyl methacrylae (HEMA) and methyl methacrylic acid (MMA) polymers using four different cross linking agents like EGDMA, DEGDMA,TriEGDMA and TEGDMA were synthesized and characterized by FTIR and DSC studies. Particle size distribution, shape and surface texture studies were conducted by microscopic methods. The 'nd' values subjected to ANOVA indicated no significant influence of the cross-linking agents used in different concentrations. Dynamic swelling studies of polymeric beads conducted in water, methanol and water-methanol mixture (1:1) suggests that the type of cross-linking agents used have very great impact on the permeation of the solvents. The diffussional kinetic exponent (n) values determined for copolymeric hydrogel beads showed a tendency to move towards Fickian transport (close to 0.43) as the hydrophilicity of the cross linking agent increases. Drug loading studies conducted with chlorpheniramine maleate and nifedipine in all batches of co-polymeric beads showed increase in percentage loading of both the drugs in the order of increasing solubility;TriEGDMADEGDMA>EGDMA. Low level of loading with respect to TEGDMA copolymer (highest solubility) is explained based on the mechanism of liquid penetrant transport in a glassy polymer.

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Recent reports1 describe a novel class of 4-hydroxycoumarins and its derivatives as Non-nucleoside Reverse Transscriptase lnhibitiors (NNRTls) In the Human immunodeficiency Virus (HIV). The chemistry of 4-hydroxycoumarins and 4-hydroxy carbostyryls (4-hydroxy 2-quinolones) was much studied for evaluating tautomerism and pharmacology as well2-4. Our current interest Is to synthesize pyrano [3,2-c) quinolines and their transformation into a variety of fused heterocycles substituted at 3,4 - positions, which may prove to be interesting antiviral agents.

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The objective of the study was to investigate the antiparkinson's activity of plain and niosomal pentoxifylline. Pentoxifylline was entrapped in niosomes by lipid layer hydration method using Span 60, cholesterol and dicetyl phosphate (10 mg : 10 mg : 2.5 mg). The antiparkinson's activity was investigated on cataleptic score in haloperidol-induced catalepsy model, and locomotor activity in reserpine antagonism and adenosine antagonism at different doses of plain pentoxifylline (40,80 mg/kg) and niosomal pentoxifylline (5,10,15 mg/kg). Plain pentoxifylline (80 mg/kg) and niosomal pentoxifylline (5,10,15 mg/kg) gave significant improvement in haloperidol-induced catalepsy. Plain pentoxifylline (80 mg/kg) and niosornal pentoxifylline (10, 15 mg/kg) showed significant increase in locomotor avtivity of reserpinetreated mice and adenosine-treated rats. Results suggest that pentoxifyl!ine may prove to be an effective drug in Parkinson's treatment as an adjuvant.

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Ten commercial sustained release (SR) tablets of diclofenac sodium (DS) were evaluated for in vitro release characteristics in pH 7.4 medium. The rate and extent of drug release were highly variable for these tablets. Five batches of sustained and controlled release matrix tablet of DS were fabricated using polymers, like carboxymethyl cellulose (CMC) or carbopol 974P (Carbopol) alone or in combinations using different ratios, and were evaluated for physical characteristics and drug release performance. The results clearly indicated that batches prepared with admixed polymers exhibited more sustained and controlled release of DS In comparison to most of the commercial tablets. The treatment of data for zero-order, first-order and Higuchi's square root of time equations showed that all the fabricated tablets provided zero-order drug release profiles.

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Bioflavonoids have a variety of biological effects in various mammalian cell systems both in vitro and in vivo. There are very few reports on their pharmacokinetics following administration in pure forms. Bioflavonoids have been implicated in quit a few drug interactions. These interactions seem to Involve Cytochrome P450 and/or P-glycoprotein. In this review the available details on pharmacokinetics of various bioflavonoids in animals and human and the influence on Cytochrome P450 and P-glycoprotein have been presented. Further, the pharmacokinetic parameters like Cmax Tmax T1/2 and AUC of bioflavonoids and the effect of dose on these parameters have been discussed. The available information on bioflavonoids biotransformations, such as methylation, sulfo-or glucuro-conjugations by different transferases in liver, has been reported. Different metabolites of quercetin (a widely investigated molecule), their metabolic pathways, clearance and volume of distribution of different bioflavonoids have been cited. Bioflavonoids have been reported to Interact with cytochrome P450 lsozymes particularly with 3A4 series and therefore, may alter the disposition of the concurrently administered drugs. P-glycoprotein, an important membrane protein, is produced as a result of mdr1 gene expression and is responsible for development of cytotoxic drug resistance in cancer. It has been reported that P-glycoprotein activity seems to be modulated by bioflavonoids. The reports on modulation of P-glycoprotein by bioflavonoids using cell line models have been reviewed and presented.

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5-Hydroxytryptamine (5-HT) is an important neurotransmitter and hormone/paracrine agent mediating various enteric functions. Its precise physiological, pathological and pathophysiological role remains nuclear. Nitric Oxide (NO) is involved in the physiological modulation of peristalsis and intestinal transit by interacting with the part of neuronal mechanisms and affecting the gastrointestinal musculature. This study investigated the role of Nitric Oxide in 5-HT-induced intestinal motility and diarrhea. Intraperitoneal administration of 5-HT, produced a dose-related increase in the incidence of diarrhea in fasted mice. 5-HT (0.1 mg/kg i.p.) Induced diarrhea was inhibited by NG-Nitro-L-arginine ( L-NNA) (1-30 mg/kg) dose dependently. The Inhibitory effect of L-NNA was reversed by L-arginine (50-300 mg/kg i.p.) dose dependently but not by D-arginine (100 mg/kg i.p.). Subcutaneous administration of 5-HT (0.5-2.0 mg/kg) produced a dose-related increase in intestinal transit, 5-HT(1.0 mg/kg, s.c.) induced increased intestinal motility was not modified by L-NNA (1.0-40 mg/kg, i.p.) L-arginine (50-300 mg/kg i.p.) dose dependently Inhibited 5-HT-induced intestinal motility, which had been reversed by L-NNA (5-20 mg/kg, i.p.). L-NNA lnhibited the effect of L-arginine, without modifying the 5-HT-induced intestinal motility. These results provide evidence that nitric oxide may play a role in diarrhea, but not that of the 5-HT-induced intestinal motility in the rat in vivo.

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Diclofenac sodium was formulated as dual coated enteric spheres for Intestinal specific drug delivery using enteric polymers like cellulose acetate phthalate and ethyl cellulose. The dual coating was given using a new process composed of wet granulation and thermal change methods using both the polymers. The new process was analyzed for its capability to produce spheres of uniform size, good flow ability, uniform drug loading, and maximum entrapment efficacy and the absence of interaction between drug and process parameters as well as polymers. In vitro release study was carried out in simulated gastric fluid for first 2 h and In simulated intestinal fluid for next 6 h. The best formulation B3, which contained cellulose acetate phthalate and ethyl cellulose in the concentration of 10:90 at 1:1.5 drug-polymer ratio was further evaluated using in vivo models for its Pharmacodynamic efficacy and ulcerogenicity.

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Bioequivalence studies are performed to demonstrate that two pharmaceutically equivalent products are equal in rate and extent of absorption in vivo. Following on from developments in the pharmaceutical industry and government mandates in the 1970's and 1980's and since the early 1990's, average bioequivalence has served as the international standard for demonstrating that two formulations of drug product will provide the same therapeutic benefit and safety profile when used in the marketplace. Population (PBE) and Individual (IBE) bioequivalence has been the subject of intense international debate since methods for their assessment were proposed in the late 1980's. Guidance has been proposed by the Food and Drug Administration of theUnited States Government for the implementation of these techniques in the pioneer and generic pharmaceutical industries. A previous article described the basis for bioequivalence and discussed the development of techniques for design and analysis in average bioequivalence assessment. This paper, the conclusion of this series, describes the implementation of average bioequivalence in the pharmaceutical industry, and discusses the development of population and individual bioequivalence.

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Spiroazetidinones synthesized from the reaction of diphenylketene, generated in situ from thermal decomposition of azibenzil, with 3-arylimino-l-methyiindol-2-ones and with 3-aryliminobornan-2-ones have been screened for antibacterial and antifungal activities. The compounds have considerable antibacterial and antifungal activities.

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Three simple and sensitive spectrophotometric methods (A-C) in visible region have been developed for the determination of chlorzoxazone. The reactions in all the three methods (A-C) are stoichiometric oxidations when the drug is treated with an excess of oxidant [nitrous acid (HNO2), method A; Nbromosuccinimide (NBS), method B; chloramines T (CAT), method C] in acidic medium. The unreacted oxidant is then estimated calorimetrically by using an oxidisable dye [cresyl fast violet acetate CFVA), method A; celestine blue (CB), method B; Gallocyanine (GC), method C]. Beer's law limits for methods A, B and C are 0.4 - 4.0 μg/ml, 0.4 5.0 μg/ml and 2-12 μg/ml respectively. No interference was observed from tableting additives and the applicability of the methods was examined by analyzing tablets containing chlorzoxazone.

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