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Biomedical subjects

D K Majumdar

Publications and source records attributed to D K Majumdar.

At least 19 recordsLinked to original sources
PubMed2006

Polyvinyl alcohol--gelatin patches of salicylic acid: preparation, characterization and drug release studies.

Polyvinyl alcohol-gelatin patches were developed and salicylic acid was incorporated at different stages of preparation of the patches. The patches were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry, tensile strength test, and scanning electron microscopy. The release patterns of the drug from the patches were also studied. The FTIR spectra of the blank patch indicated complete esterification of the free carboxylic groups of gelatin. The XRD studies indicated a crystalline form of the drug entrapped in the patches. Release of the drug from the patches followed Higuchian/Fickian kinetics indicating a diffusion-controlled release process.

Absorption↗
PubMed2006

Insulin loaded eudragit L100 microspheres for oral delivery: preliminary in vitro studies.

Eudragit L100 microspheres were prepared using water-in-oil-in water (w/o/w) emulsion-solvent evaporation with polysorbate 20 as dispersing agent in the internal aqueous phase, and PVA/PVP as stabilizer in the external aqueous phase. Smaller internal and external aqueous phases provided higher drug encapsulation. The PVA-stabilized microspheres having maximum drug encapsulation (84.5 2.8%) released 7% insulin at pH 1.0 in 2 h. In phosphate buffer (pH 7.4), microspheres showed an initial burst release of 21% in 1 h with additional 35% release in the next 5 h. The smaller the volumes of internal and external aqueous phases, the lower the initial burst release. The release of drug from microspheres followed Higuchi kinetics. Scanning electron microscopy of PVA stabilized microspheres demonstrated spherical particles with smooth surface and laser diffractometry revealed a mean particle size (V(m)) of 59.11 30 m.

Administration, Oral↗
PubMed2005

Antibacterial activity of Ocimum sanctum L. fixed oil.

Ocimum sanctum fixed oil showed good antibacterial activity against Staphylococcus aureus, Bacillus pumilus and Pseudomonas aeruginosa, where S. aureus was the most sensitive organism. Sesame and soyabean oils also showed moderate activity against S. aureus. Higher content of linolenic acid in O. sanctum fixed oil could contribute towards its antibacterial activity. The antibacterial activity combined with anti-inflammatory and analgesic activities of the oil, could make it useful in inflammatory disorder resulting from staphylococcal infection.

Anti-Infective Agents↗
PubMed2002

Effect of preservative, antioxidant and viscolizing agents on in vitro transcorneal permeation of ketorolac tromethamine.

The influence of formulation additives, e.g. preservative, antioxidant and viscolizing agents on in vitro transcorneal permeation of ketorolac tromethamine from 0.5%(w/v) aqueous drop was studied using goat cornea. Permeation characteristics of drug, from selected formulations, through excised rabbit cornea were also evaluated. Aqueous solution of ketorolac tromethamine (0.5% w/v), pH 6.5 or 7.0 having ionic strength 0.2, was prepared. To this solution perservatives either alone or in combination with other additives were added to have drops of various composition. Permeation studies with goat cornea showed maximum permeation of ketorolac tromethamine from formulation containing benzalkonium chloride and disodium edetate. Increase in viscosity of drop resulted in decreased permeation of drug. Formulation containing benzalkonium chloride and disodium edetate also increased permeation of drug through rabbit cornea. Cumulative permeation of drug through rabbit cornea was found to be 2.3-2.4 fold higher than that observed with goat cornea.

Animals↗
PubMed2001

Effect of Ocimum sanctum fixed oil on blood pressure, blood clotting time and pentobarbitone-induced sleeping time.

Ocimum sanctum fixed oil produced hypotensive effect in anaesthetised dog, which seems to be due to its peripheral vasodilatory action. The oil increased blood-clotting time and percentage increase was comparable to aspirin and could be due to inhibition of platelet aggregation. The oil also increased pentobarbitone-induced sleeping time in rats indicating probable inhibitory effect of oil towards cytochromic enzyme responsible for hepatic metabolism of pentobarbitone.

Animals↗
PubMed2001

Permeation through cornea.

The permeability of the cornea to drugs is clinically important because it is the major factor determining the efficacy of topically applied ophthalmic preparations. With this perspective, the present article gives a brief update and overview of corneal structure and proposed mechanisms of permeation. Physiological, physicochemical and formulation factors affecting drug permeation through cornea are highlighted. Influence of ocular penetration enhancers on drug permeation is also discussed.

Animals↗
PubMed2000

Ketorolac entrapped in polymeric micelles: preparation, characterisation and ocular anti-inflammatory studies.

Polymeric micelles made of copolymer of N-isopropylacrylamide (NIPAAM), vinyl pyrrolidone (VP) and acrylic acid (AA) having cross-linkage with N,N'-methylene bis-acrylamide (MBA) were used as host carrier in which up to 30%w/w ketorolac (free acid) was entrapped to make the formulation. The lyophilised powder was used for physical characterisation. The drug entrapment was found to be about 80% and the formulation was stable for 8-10 days at room temperature. The smaller the amount of ketorolac dissolved into the micelles, the longer was the formulation shelf life. The size of the particles as measured by dynamic light scattering was found to be around 35 nm diameter at 25 degrees C. TEM picture showed spherical particles. The structure of the polymer and its morphology were characterised by FTIR, NMR and XRD measurements. IR data indicated weak interaction between polymer and ketorolac in the encapsulated system. NMR spectra indicated rigid polymer backbone with intermittent iso-propyl group in the chain. XRD spectra showed significant loss of crystallinity of the drug while being entrapped in the polymeric micelles. The release of drug in aqueous buffer (pH 7.2) from the polymeric micelles at 25 degrees C were 20 and 60% after 2 and 8 h respectively and is temperature and pH dependent. In vitro corneal permeation studies through excised rabbit cornea indicated two fold increase in ocular availability with no corneal damage compared to an aqueous suspension containing same amount of drug as in nanoparticles. The formulation showed significant inhibition of lid closure up to 3 h and PMN migration up to 5 h compared to the suspension containing non-entrapped drug, which did not show any significant effect.

Acrylamides↗
PubMed1999

Evaluation of the gastric antiulcer activity of fixed oil of Ocimum sanctum (Holy Basil).

The fixed oil of Ocimum sanctum L. (Labiatae) was found to possess significant antiulcer activity against aspirin-, indomethacin-, alcohol-, histamine-, reserpine-, serotonin- and stress-induced ulceration in experimental animal models. Significant inhibition was also observed in gastric secretion and aspirin-induced gastric ulceration in pylorus ligated rats. The lipoxygenase inhibitory, histamine antagonistic and antisecretory effects of the oil could probably have contributed towards antiulcer activity. O. sanctum fixed oil may be considered to be a drug of natural origin which possesses both anti-inflammatory and antiulcer activity.

Animals↗
PubMed1999

Effect of Ocimum sanctum fixed oil on vascular permeability and leucocytes migration.

Ocimum sanctum fixed oil significantly inhibited the rise in protein concentration and dye leakage in peritoneal fluid in experimentally induced peritoneal inflammation in mice. In carrageenan-induced pleurisy in rats, the fixed oil showed significant inhibition of leucocytes migration in the pleural exudate. The results suggest that the fixed oil can inhibit enhancement of the vascular/capillary permability and leucocyte migration following inflammatory stimulus.

Animals↗
PubMed1997

Evaluation of antiinflammatory activity of fatty acids of Ocimum sanctum fixed oil.

Ocimum sanctum fixed oil and linolenic acid were found to possess significant antiinflammatory activity against PGE2, leukotriene and arachidonic acid-induced paw edema. Plant lipids like linseed oil and soyabean oil containing linolenic acid when tested along with O. sanctum fixed oil, also showed significant inhibition of carrageenan-induced paw edema. The results suggest that linolenic acid present in O. sanctum fixed oil has the capacity to block both the cyclooxygenase and lipoxygenase pathways of arachidonate metabolism and could be responsible for the antiinflammatory activity of the oil.

Animals↗
PubMed1997

Effect of concentration, pH, and preservative on in vitro transcorneal permeation of ibuprofen and flurbiprofen from non-buffered aqueous drops.

Influence of drug concentration, pH of aqueous drops and some commonly used preservatives on in vitro transcorneal permeation of ibuprofen and flurbiprofen were investigated using goat cornea. Increase in drug concentration in the drops made in normal saline resulted in increase in quantity permeated but decrease in cumulative percent permeation of both drugs. Permeation of each drug from 0.5% drops was maximum at acidic pH (6.4) and decreased with increase in pH of the drops. Normal saline, as a vehicle, favoured permeation of each drug, hence retained in the formulation. Benzalkonium chloride and chlorobutanol enhanced cumulative percent permeation of ibuprofen while benzalkonium chloride and phenyl mercuric nitrate increased permeation of flurbiprofen. Benzalkonium chloride being incompatible with 0.5% drops (pH 6.4) of either drug, chlorobutanol appears suitable for ibuprofen drops and phenyl mercuric nitrate for flurbiprofen drops.

Animals↗
PubMed1997

In vitro transcorneal permeation of ketorolac tromethamine from buffered and unbuffered aqueous ocular drops.

In vitro transcorneal permeation of ketorolac tromethamine from 0.5% w/v solutions containing equimolar (0.02 M) concentrations of citrate (pH 6.5), phosphate (pH 6.5 and 7), citrate-phosphate (pH 7) and borate (pH 7) buffers was studied using goat cornea. Cumulative % permeation was maximum with phosphate buffered drops of pH 6.5. The effect of pH and ionic strength on permeation of ketorolac tromethamine from buffered (phosphate) drops was next investigated. Cumulative % permeation of ketorolac tromethamine from buffered drops was pH dependent being maximum at pH 4.5. Adjustment of ionic strength of drops to 0.2 resulted in decreased permeation of drug. Permeation of ketorolac tromethamine from unbuffered drops of varying pH and ionic strength 0.2 was also pH dependent and was maximum at pH 4.5. Buffered drops of pH between 4.5-5.5, ionic strength 0.2, provided better permeation of drug compared to unbuffered drops of same pH and ionic strength. Above pH 6.5 unbuffered drops showed better permeation than buffered drops. Increase in molarity of phosphate buffer (pH 4.5) used in making drops, between 0 to 0.15 M increased permeation. Aqueous drops of ketorolac tromethamine formulated in 0.15 M phosphate buffer of pH 4.5 and ionic strength 0.2 showed maximum cumulative % permeation in vitro. Considering lacrimation induced drug loss in vivo, by buffer of high concentration, ketorolac tromethamine drops formulated in buffer of low molarity, pH 4.5 and ionic strength 0.2 appear suitable.

Animals↗
PubMed1997

In vitro transcorneal permeation of ketorolac from oil based ocular drops and ophthalmic ointment.

Transcorneal permeation of ketorolac from oil based ocular drops and ophthalmic ointments was studied in vitro, using goat cornea. Cumulative (%) permeation of ketorolac through cornea, was found to be maximum with 0.2% (w/v) ketorolac drops in sesame oil followed by formulations in corn oil and soyabean oil. Ketorolac 1% (w/v) drops in castor oil increased the quantity permeated but cumulative (%) permeation was less. Permeation profiles of ketorolac were in consistence with the partition characteristic of drug between oil and aqueous phase. Formulations favouring corneal permeation of ketorolac increased corneal hydration. Addition of benzyl alcohol, a preservative, to oil drops reduced permeation of ketorolac and corneal hydration indicating possible protective effect of benzyl alcohol against corneal damage. Permeation studies on ointment formulations containing either ketorolac acid or ketorolac tromethamine salt indicated better permeation for formulation containing ketorolac tromethamine aqueous solution. Thus for better transcorneal permeation, ketorolac 0.2% (w/v) drops, formulated in sesame oil, containing 0.5% v/v benzyl alcohol and ophthalmic ointment containing 0.5% (w/w) ketorolac tromethamine in dissolved state appear suitable.

Animals↗
PubMed1996

Evaluation of anti-inflammatory potential of fixed oil of Ocimum sanctum (Holybasil) and its possible mechanism of action.

The fixed oil of Ocimum sanctum (Labiatae) was found to possess significant anti-inflammatory activity against carrageenan- and different other mediator-induced paw edema in rats. Significant inhibitory effect was also observed in castor oil-induced diarrhoea in rats. It also inhibited arachidonic acid and leukotriene-induced paw edema. The results of anti-inflammatory activity of Ocimum sanctum support the dual inhibition of arachidonate metabolism as indicated by its activity in inflammation models that are insensitive to selective cyclooxygenase inhibitors. On the basis of the findings it may be inferred that Ocimum sanctum may be a useful anti-inflammatory agent which blocks both the pathways, i.e. cyclooxygenase and lipoxygenase, or arachidonic acid metabolism.

Adrenalectomy↗
PubMed1996

Chemical and pharmacological studies on fixed oil of Ocimum sanctum.

Gas liquid chromatographic analysis of fixed oil of O. sanctum revealed the presence of five fatty acids (stearic, palmitic, oleic, linoleic and linolenic acids). The triglyceride fraction of the oil showed higher protection compared to fixed oil against carrageenam-induced paw edema and acetic acid-induced writhings in rats and mice, respectively. The pharmacological activity of the fixed oil could be attributed to its triglyceride fraction or the fatty acids.

Analgesics↗