Antibacterial Interaction of Crude Methanol Extract of Garcinia kola Seed with Gatifloxacin

Purpose: Concurrent use of orthodox and herbal medicines is likely to precipitate an overall effect which may or may not be beneficial to the patient. The objective of this study was to evaluate the antimicrobial interaction between the methanol extract of Garcinia kola seed (GKS) which is chewed habitually as a masticatory in many rural communities in Africa and gatifloxacin (GAT), a fourth generation fluoroquinolone. Method: The antimicrobial interaction between these two agents was evaluated by a modification of the checkerboard technique using Bacillus subtilis and Staphylococcus aureus as the test organisms. Result: Results obtained showed that the minimum inhibitory concentration (MIC) of gatifloxacin against both organisms was 1.0 μg/ml while the MICs of the G. kola seed extract were evaluated to be 1.562 mg/ml and 3.125 mg/ml respectively against B. subtilis and S. aureus. Upon combination, synergism was manifested serially against B. subtilis in ratios of 9(GAT):1(GKS) down to 6(GAT) :4(GKS) after which additivity, indifference and antagonism, in that order, were manifested as the ratio of GKS increased in the combination. Against S. aureus, the combined interaction showed a somewhat irregular pattern of effect, including synergism at GAT:GKS ratios of 9:1, 2:8 and 1:9 , antagonism at ratios of 8:2, 5:5 and 4:6 and indifference at GAT:GKS ratios of 7:3, 6:4 and 3:7. Conclusion: The results from this study suggest that the effect of combination of the methanol extract of GKS with gatifloxacin was dependent not only on the ratio of combination but also on the test organism employed for the evaluation. Overall, the combined antimicrobial effect of the interaction between GKS and gatifloxacin was predominantly synergistic against B.subtilis. Keywords: Garcinia kola seed, antibacterial interaction, checkerboard technique, Bacillus subtilis, Staphylococcus aureus, gatifloxacinTropical Journal of Pharmaceutical Research Vol. 7(4) 2008: pp. 1159-116

Spectroscopic Studies of the Electron Donor-Acceptor Interaction of Chloroquine Phosphate with Chloranilic Acid

Purpose: The electron donor-acceptor interaction between drugs which act as electron donors and some electron-deficient compounds (&#960 acceptors) has severally been utilized as an analytical tool for the quantitation and qualitative assessment of such drugs. The objective of this study, therefore, was to develop an assay procedure for dosage forms of chloroquine phosphate based on its reaction with chloranilic acid which resulted in the formation of a charge-transfer complex. Methods: The complex formation between chloroquine phosphate and chloranilc acid as evidenced by the instantaneous change in colour of a solution of chloranilic acid in dioxan from yellow to purple upon addition of a solution of chloroquine phosphate in chloroform was monitored spectrophotometrically to determine the wavelength of maximum absorption. The stoichiometry of the complex formed was evaluated using the Job\'s continuous variation method while the thermodynamics of the complex was evaluated spectrophotometrically with the aid of the Benesi-Hildebrand plot. Results: Spectrophotometric absorption studies showed evidence of the formation of strongly bonded and highly stable charge-transfer complex between chloroquine phosphate and chloranilic acid in a 3:2 stoichiometry in non-aqueous medium. The transitions involved were detected at wavelengths longer than those of the individual pure substances in the visible region of the spectrum. Conformity with Beer\'s law was evident over the concentration range 0.8 – 8.0 mg/100 ml of chloroquine phosphate; thus making it possible for an accurate quantitative determination of the drug. Conclusion: The studied complexation phenomenon formed a basis for the quantitative determination of both pure samples and individual dose units of chloroquine phosphate and is considered a simple, sensitive and precise analytical tool with high accuracy for routine analysis of chloroquine phosphate in developing countries where sophisticated analytical instruments may not be available. Keywords: Spectroscopic studies, Electron Donor-Acceptor Interaction, Chloroquine phosphate, Chloranilic acid.Tropical Journal of Pharmaceutical Research Vol. 8 (1) 2009: pp. 87-9

Formulation and Evaluation of Glutaraldehyde-Crosslinked Chitosan Microparticles for the Delivery of Ibuprofen

Tropical Journal of Pharmaceutical Research is indexed by Science Citation Index (Purpose: Toformulate glutaraldehyde-cross-linked chitosan-based microparticles and evaluate its suitability for the delivery of ibuprofen, a BCS class II drug.Methods: Ibuprofen-loaded chitosan microparticles were prepared by emulsification-cross-linking technique using glutaraldehyde saturated toluene (GST) as the cross-linking agent. The microparticles were characterized with respect to morphology, particle size, microparticle yield and entrapment efficiency. The swelling behaviour of the particles and ibuprofen release were assessed in both simulated gastric fluid (SGF) without pepsin (pH 1.2) and simulated intestinal fluid (SIF) withoutpancreatin (pH 7.4).Results: Discrete and free-flowing microparticles of size range 100.05 ± 8.82 to 326.70 ± 10.43 ìm were obtained. The microparticles had a high yield (69.2 to 99.2 %) and exhibited greater water sorption capacity in SIF (122.2 %) than in SGF (60 %). Furthermore, the microparticles cross-linked with 10 ml of GST entrapped the highest amount of drug (23.32 ± 0.97 %) while those cross-linked with 25 ml GST had the highest yield of the microparticles (99.19 % ), and highest water sorption in SIF (122.2 %). Up to 93.6 % of the entrapped drug was released in SIF from microparticles cross-linked with 25 ml of GST. Drug release from microparticles cross-linked with 20 and 30 ml each of GST showed a biphasic pattern.Conclusions: Entrapment of ibuprofen in glutaraldehyde-cross-linked chitosan microparticles can be exploited to target and control the release of the drug and possibly reduce its gastro-erosive side effects.Keywords: Chitosan microparticles, Ibuprofen, Oral delivery, Gastrointestinal, Glutaraldehyde

Stability studies and degradation kinetics of some commercially available metronidazole suspensions in Nigeria

The present study was undertaken to investigate the effect of temperature on the degradation of metronidazole suspensions commercially available in Nigeria. Six different brands of metronidazole suspension, coded as MTZ A to MTZ F, were evaluated for their active contents using microbiological assay method. They were stored at three different elevated temperatures of 30 °C, 37 °C and 45 °C and at each temperature, the degradation rate constant was determined from a plot of logarithm of concentration versus time. The shelf-life of the various brands of the drug was predicted from Arrhenius equation and compared with their manufacturers’ label claim. Results confirmed that increase in temperature led to increase in the degradation rate constants for the various brands of the drug. The shelf-life ranged from 35.0 to 80.8 weeks for all the brands studied while the percentage of the calculated shelf -life in comparison with the label claim ranged from 29.3 % to 67.3 % of the manufacturers’ stated shelf-life. This study has shown that increase in temperature causes increased degradation of metronidazole suspensions. It may be concluded that some of the metronidazole suspensions commercially available in Nigeria may have expired long before the actual date stated on the product labels

Ibuprofen-loaded microspheres based on a co-polymer of Eudragit® RS 100 and RL 100: Formulation, swelling and drug release properties

The objective of this study was to encapsulate ibuprofen in microspheres based on a co-polymer of Eudragit® RS100 and RL100 with a view to achieving a controlled release of the incorporated drug. The microparticles were prepared by an o/o emulsion-solvent evaporation method using varying polymer ratios and polymer concentrations as independent variables. The prepared microspheres were characterized with respect to particle size, morphology, swelling properties and bioadhesiveness. The in vitro release profile of ibuprofen from the formulation was evaluated in 0.1 N HCl (pH 1.2) and phosphate buffered saline (pH 7.4) to simulate acidic and alkaline release media respectively. The formulated microspheres were white, almost spherical in shape with some of the batches being free-flowing. Particles having a mean diameter in the range of 350 to 460 μm were obtained. The particle size distribution was polydisperse and was influenced by varying polymer-polymer ratios. The drug entrapment efficiency varied between 58.45-63.7 % while percent mucoadhesion in the range of 80 to 100 % was recorded. A slow release of ibuprofen from the microspheres occurred in 0.1 N HCl, while in phosphate buffered saline, higher amounts of the drug were released. Release of ibuprofen was found to be diffusion controlled and influenced by the drug - polymer ratio and the relative proportions of the two polymers in the formulation. The results from this study indicate that microspheres based on a co-polymer of Eudragit® RS100 and RL100 could serve as a promising delivery vehicle for ibuprofen when the goal is to minimize the gastro-erosive adverse effects of the drug.Keywords: microspheres, ibuprofen, co-polymer, Eudragit, release profile, swellingJournal of Pharmaceutical and Allied Sciences, Vol. 7 No. 3 (2010

Antibacterial Interaction of Crude Methanol Extract of Garcinia kola Seed with Gatifloxacin

Purpose: Concurrent use of orthodox and herbal medicines is likely to precipitate an overall effect which may or may not be beneficial to the patient. The objective of this study was to evaluate the antimicrobial interaction between the methanol extract of Garcinia kola seed (GKS) which is chewed habitually as a masticatory in many rural communities in Africa and gatifloxacin (GAT), a fourth generation fluoroquinolone. Method: The antimicrobial interaction between these two agents was evaluated by a modification of the checkerboard technique using Bacillus subtilis and Staphylococcus aureus as the test organisms. Result: Results obtained showed that the minimum inhibitory concentration (MIC) of gatifloxacin against both organisms was 1.0 µg/ml while the MICs of the G. kola seed extract were evaluated to be 1.562 mg/ml and 3.125 mg/ml respectively against B. subtilis and S. aureus . Upon combination, synergism was manifested serially against B. subtilis in ratios of 9(GAT):1(GKS) down to 6(GAT) :4(GKS) after which additivity, indifference and antagonism, in that order, were manifested as the ratio of GKS increased in the combination. Against S. aureus , the combined interaction showed a somewhat irregular pattern of effect, including synergism at GAT:GKS ratios of 9:1, 2:8 and 1:9 , antagonism at ratios of 8:2, 5:5 and 4:6 and indifference at GAT:GKS ratios of 7:3, 6:4 and 3:7. Conclusion: The results from this study suggest that the effect of combination of the methanol extract of GKS with gatifloxacin was dependent not only on the ratio of combination but also on the test organism employed for the evaluation. Overall, the combined antimicrobial effect of the interaction between GKS and gatifloxacin was predominantly synergistic against B.subtilis

Application of Conformational Space Search in Drug Action

The role of conformational space in drug action is presented. Two examples of molecules in different therapeutic groups are presented. Conformational space search will lead to isolating the exact conformation with the desired medicinal properties. Many conformations of a plant isolate may exist which are active, weakly active or inactive. Key Words: Conformational, Space, Drug Action Bio-Research Vol.1(2) 2003: 69-7

Evaluation of In vitro antimicrobial activity and release behaviour of ointments and applications containing extract of the lichen Ramalina farinaceae (L.) ach

The extract of the lichen Ramalina farinacea was obtained via cold maceration with methanol. The minimum inhibitory concentrations (MICs) of the methanolic extract against Candida albicans and Pseudomonas aeruginosa were determined using the agar diffusion method. Ointments and applications were prepared with the extract using three different concentration levels (MIC, 2MIC and 4MIC of the extract against C. albicans). The antimicrobial and release properties of the applications and ointments were evaluated against the various test organisms (B. subtilis, S. aureus, E. coli, S. typhi, A. niger, C. albicans, Klebseilla spp and P. aeroginosa) using the agar diffusion technique. Results revealed that S. aureus was the most sensitive organism while P. aeruginosa was most resistant to the lichen extract. The application was generally better, in terms of rapidity of action of extract than the ointment. The application performed better than the control (Cannex cream containing Clotrimazole) against bacteria; the reverse was true against the fungi. Overall, the anitmicrobial activity of both the application and the ointment was found to be concentration dependent.Keywords: Ramalina farnacea, extract, antimicrobial activity, release behaviour, ointments and applicationsPlant Products Research Journal Vol. 9 2005: 6-1

Qualitative detection of some electron donor drugs on thin-layer plates: chloranilic acid as the locating reagent in non-aqueous media

A chromatographic procedure for the qualitative detection of diethylcarbamazine citrate, moclobemide and promethazine hydrochloride on thin-layer plates is presented. The detection reactions, which occurred instantaneously, were found to utilize the complex formation between chloranilic acid acting as the election acceptor and the drugs acting as the electron donors in non-aqueous media. Using the intensity of the purple coloration of the different complexes as a basis, it was possible to gain some insight into the degrees of bonding between chloranilic acid and each of the drugs studied. The results from this study corroborate earlier findings regarding the thermodynamic interactions of these drugs with chloranilic acid. Key words: Qualitative detection; electron donor drugs; chloranilic acid; thin-layer plates; complex formation; non-aqueous media. Journal of Pharmaceutical and Allied Sciences Vol.2(2) 2004: 226-23