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.

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.

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.

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.

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.

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.

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.

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.

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.