Evaluation of the Quality of Commercial Antibacterial Discs Available in Nigeria.

Aims: This study was undertaken to compare the quality and efficacy of six brands of antibacterial discs that are commercially available in Nigeria. Methodology: The brands evaluated include two foreign brands (Oxoid and Abtek) and four local brands (Optudisc, Polydisc, Maxidisc and Jirehdisk). The brands were analyzed by antibiotic susceptibility testing (AST) using laboratory isolates of Staphylococcus aureus and Escherichia coli to measure the antimicrobial performances of the brands; and UV-Vis spectrophotometry to measure the absorbances of antibiotics extracted from antibiotic discs of the various brands. Results: All of the brands of antibacterial discs of under study exhibited variations in their antimicrobial performances and UV-absorbances. This was observed where some of the discs with lower stated potencies produced inhibition zones and absorbances far greater than similar discs from other brands with higher stated potencies. Also, discs of the same stated potencies showed variable results in both the antibiotic susceptibility testing (AST) and UV-Vis spectrophotometric analyses. Coefficients of variation greater than 5%, which indicates high disc-to-disc variation and unsatisfactory reproducibility, were recorded highest among the local brands during the AST. All the brands with multidisc panels, except the Abtek and Polydisc brands, produced some zones of inhibition that are unreadable. Of all the zones of inhibition that were unreadable, Optudisc brand recorded the highest rate (36·7%), while 6·7% of discs of Jirehdisk brand and 6·7% of discs of Maxidisc brand produced inhibition zones that were unreadable. Conclusion: All brands of susceptibility discs evaluated in this study except the Oxoid and Abtek brands manifested poor quality and performed below expected standard, though one of the local brands (Polydisc) performed closest to the foreign brands. With further improvement in quality, these brands may be recommended for use in Nigeria.

Quality Assessment of Some Brands of Tetanus Toxoids Marketed in Open Markets in South-Eastern Nigeria.

Aims: This study was designed to verify the immunogenicity (potency) and the safety of tetanus toxoid vaccines marketed in three large open drug markets in South-Eastern Nigeria. Methodology: Tests for Sterility, formaldehyde concentrations, specific toxicity, endotoxin, and immunogenicity (potency) were conducted on three different brands of tetanus toxoids (Brand α - from Ariaria Drug Market, Aba-Abia State; Brand β - from Ogbete Drug Market, Enugu State; and Brand γ - from Bridge-Head Drug Market, Onitsha-Anambra State). Results: All vaccine brands studied passed the sterility testing, but did not comply with the 2011 BP specifications on free formaldehyde concentration, which stipulates that the free formaldehyde concentration should not exceed 0.02%. The three vaccine brands did not show specific, abnormal, or general toxicity, but contained different amounts of endotoxins. The result of the potency testing showed that the three brands were immunogenic and elicited specific antibodies against tetanus toxin; but brand γ was the most immunogenic since it elicited the highest titers of total IgG, IgG1, and IgG2a followed by brand α, and then brand β. Conclusion: Generally, the quality control tests carried out on these three commercial brands of tetanus toxoids marketed in Nigeria showed that they do not comply with all the pharmacopeial standards on quality and safety required for vaccines of this nature. Therefore, we conclude that some of the tetanus toxoids marketed in open drug markets in Nigeria are substandard and may be responsible for the failures of these vaccines used for immunization in the country.

Optimized Artemether-loaded Anhydrous Emulsion.

Objective: The objectives of this study were to identify stable anhydrous emulsions via pseudo ternary phase diagram, optimize artemether-loaded batches using factorial design and subsequently evaluate the antimalarial activity. Methodology: Using labrasol®, triacetin® and lauroglycol 90® as the surfactant, oil and co-surfactant respectively, pseudo ternary phase diagram was generated from the quantitative titration of water with the anhydrous emulsion. Stable combinations from the phase diagram were subjected to a 23 full factorial experimental design. The 22 softwaregenerated formulations were experimentally formulated and characterized for droplet size, polydispersity index, viscosity and thermodynamic stability. Droplet size was chosen and subsequently fitted into the Response column of the software, thus prompting the generation of graphs and Desirability table of 125 predicted formulations. Out of the 125 predictions, three with the least droplet sizes (less than 100 nm) were adjudged as optimized batches. Subsequently, they were formulated, converted to powder by adsorption on magnesium aluminum metasilicate and evaluated. Antimalarial effectiveness of the drug-loaded formulation was also investigated. Results: Triacetin® most significantly (P<0.05) contributed to droplet size variation. The droplet size of the experimental formulations approximated that of the statistical predictions. The anhydrous emulsions (AEs) were powderable and the granulations rated fair and passable according to Carr’s scale. Artemether-loaded anhydrous emulsion (AE) demonstrated highest antimalarial activity. Conclusion: We therefore conclude that optimization proved a useful tool for the identification of excipient proportions with optimal effects.

Formulation and Evaluation of Niosomes of Benzyl Penicillin.

Benzylpencillin niosomes were formulated using thin film hydration technique. The resultant niosomes were evaluated using surface morphology, particle size and its distribution, encapsulation efficiency, In vitro drug release, in vivo bioavailability and In vitro antimicrobial activity parameters. Both short (3 h) and long term (24 h) stability studies were carried out on the formulations. The lipid-surfactant ratio and the presence of cosurfactant were identified as the key variables that affect performance of the formulations. The niosomes particle sizes were between 1.67μm to 2.22 μm. The encapsulation efficiency was found to be highest in batch A with value of 82.42 %. Batches B and C exhibited slow release, oral stability and good bioavailability in vivo. For In vitro and in vivo studies, batch B containing span 80,Tween 65 and cholesterol was particularly stable and released its drug content in a controlled manner. The Cmax for the batches were higher than that of pure drug which has value of 55.04 mg/ml in vivo. The IZD of the batches were high against the test micro organisms and all the batches exhibited antimicrobial activities greater than the unformulated drug against S. typhi, P. vulgaris and Ps. Aereuginosa.

Antimicrobial Resistance Evaluation of Organisms Isolated from Liquid Herbal Products Manufactured and Marketed in South Eastern Nigeria.

Objective: To determine the susceptibility and resistance pattern of bacteria and fungi isolates obtained from herbal anti-infective liquid preparations manufactured and marketed in South-East Nigeria to conventional antibiotics. Study Design: Experimental Place and Duration of the study: Pharmaceutical Microbiology and biotechnology Laboratory, Faculty of Pharmaceutical Sciences, Nnamdi Azikiwe University, Agulu Campus between October 2011 and March 2012. Methodology: Isolation and characterization of contaminating microorganisms were carried out using standard procedures. A total of forty-nine (49) bacteria and forty (40) fungi isolated from the herbal products were examined for susceptibility to conventional antibiotics using the disc diffusion method. The bacterial isolates were tested against ciprofloxacin, ofloxacin, amoxicillin-clavulanic acid, gentamicin, cefotaxime, ceftazidime, ceftriazone, sulphamethoxazole, tetracycline and ampicillin were employed while fungi isolates were tested against five common antifungal-griseofulvin, nystatin, ketoconazole, fluconazole and clotrimazole. The Multiple Antibiotic Resistance Index (MARI) of each of the isolated bacteria was obtained following the standard method. Result: The antimicrobial susceptibility-resistance profile of the bacteria isolates revealed that most of the bacteria were sensitive to ciprofloxacin, ofloxacin, gentamicin, and ceftriaxone, On the other hand, a good number of the isolates demonstrated high level of resistance to common antibiotics like Ampicillin, amoxycillin-clavulanic acid, trimethoprimsulphamethoxazole, and moderate level of resistance to Tetracycline, and some of the third generation cephalosporins - ceftazidime and cefotazime. Multiple Antibiotic Resistance Index (MARI) evaluation revealed that most of the isolates were resistance to more than fifty percent (50%) of the number of antibiotics used. The fungal isolates were susceptible to nystatin, ketoconazole and clotrimazole, resistance to fluconazole and high resistance recorded against griseofulvin. Conclusion: The results of this study revealed that the herbal medications can serve as a trail of spread of antibiotic-resistance genes.

Knowledge and Use of Disinfection Policy in Some Government Hospitals in South-East, Nigeria.

Aims: This study was carried out to evaluate the knowledge and use of disinfection policy in government hospitals in south-east geopolitical zone of Nigeria and to compare the three categories of government hospitals. Study Design: This was a descriptive, cross sectional study. Place and Duration of Study: Intensive Care Units and Special Care baby Units (SCBU), Departments of Pharmacy (Compounding/Storage Unit), Medical Laboratory Services, Surgery, Obstetrics and Gynecology, between February and May 2012. Methodology: A structured self administered and pre-tested questionnaires were administered to 200 randomly selected healthcare workers which included 40 Pharmacists, 59 Nurses, 55 Resident/General Practice Medical doctors and 46 Medical laboratory scientists, employed full-time in selected government hospitals in southeast geopolitical zone of Nigeria. Results: The sample size and the response rate were 200 and 100% respectively. About 53.3% of the respondents have heard of the policy, but only 24.5% of them actually know what it means. Only about 22% of all the respondents have applied the policy. The study also reveals that the level of knowledge of disinfection policy is not significantly related to the level of its application by the healthcare workers in the southeast (P-value 0.143, for chi-square and 0.49, for Pearson Correlation). Up to 78% of the healthcare workers have an idea about the different levels of disinfection. The University Teaching Hospitals seem to have better knowledge and use of the policy than the Federal Medical Centres and the General Hospitals. Conclusion: The knowledge of disinfection policy among the healthcare workers and its application is poor. This is worst in General Hospitals. There is therefore urgent need for a national policy on disinfection and health workers’ education or training on the policy and its application in all hospitals in the nation.

Antibacterial profile of extracts of Combretum micranthum G. Don against resistant and sensitive nosocomial isolates.

Combretum micranthun G. Don (Combretaceae) is reputed in folk medicine for its anti-infective properties. In this study, we screened aqueous and methanol extracts of Combretum micranthun for antibacterial activities against nosocomial bacterial isolates. The methanolic and aqueous extracts of the leaves, root-bark and stem-bark were screened against the 25 different nosocomial isolates each of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Enterococcus faecalis, Streptococcus pyogenes and Streptococcus pneumoniae isolated from patients presenting with various ailment at the University of Nigeria Teaching Hospital, Enugu using the agar well diffusion technique. The extracts of Combretum micranthun exhibited antimicrobial activities against both Gram-negative and the Gram-positive isolates including Pseudomonas aeruginosa and Staphylococcus aureaus. Generally, Pseudomonas aeruginosa and Streptococus pyogenes showed the highest level of susceptibility to the extracts of Combretum micranthun. The hot aqueous, the methanol and the cold aqueous extracts were more effective than other extracts in inhibiting all the isolates tested. The extracts of the plant C. micranthum G. Don showed high antimicrobial effectiveness against the different 200 clinical isolates of both Gram positive and Gram negative isolates screened and could therefore be harnessed as a potent antibacterial agents or could possibly provide leads for the synthesis of novel anti-infective agents.

Antagonistic antimalarial properties of pawpaw leaf aqueous extract in combination with artesunic acid in Plasmodium berghei-infected mice.

Background & objectives: Artemisinins, the main stay in the treatment of malaria are used in combinations with other antimalarials to forestall resistance, as artemisinin-combination therapies (ACTs). However, ACTs are expensive and some of the non-artemisinin components are not well-tolerated by patients. There are several folkloric and scientific proofs of the efficacy of herbal remedies for malaria. Mature leaves of Carica papaya is widely used to treat malaria in several African countries. An ACT involving a medicinal herb extract or its active constituent(s) will provide an indigenous alternative/herbal ACT. Methods: Mature fresh leaves of Carica papaya were grounded and macerated in cold distilled water for 24 h and the extract (PCE) was stored in the refrigerator for seven days. Fresh extracts were made as needed. The antiplasmodial activity of PCE and/or artesunic acid were determined by using the Peter’s 4-day suppressive test in Plasmodium berghei-infected mice. The ED50 and ED90 were calculated from the dose-response relationships. Results: The combination of 50 mg/kg of PCE and 15 mg/kg of artesunic acid produced a significant reduction of parasitemia (81.25%), compared to 50 mg/kg PCE alone (37.7%). The mean survival time of the combinations of PCE and 15 mg/kg of artesunic acid, and PCE alone followed a dose-dependent manner. The ED50 of PCE showed that it has a very good activity. The isobolar equivalent (IE) calculated from the ED90 of PCE in combination with artesunic acid showed that the interaction was antagonistic. Interpretation & conclusion: Although pawpaw alone was found to have a very good activity, its combination with artesunic acid is antagonistic. Combinations of artemisinins and pawpaw show little promise for combination therapy development.

Evidence for the spectroscopic determination of artesunate in dosage form.

BACKGROUND & OBJECTIVES: Resistance to conventional antimalarials triggered off new policies to circumvent the devastating consequences of malaria especially in the trans-Saharan Africa. The use of artemisinin-based combinations as first line drug in treatment of uncomplicated malaria was then advocated and adopted by the World Health Organization (WHO). In Nigeria, this new policy has witnessed a surge in the number of circulating brands of such combinations. Unfortunately, at present, there are no "on-the-spot" cheap and reliable assay procedures for artesunate-based combinations. This is what the present research aims to achieve. METHODS: Ultraviolet absorption spectroscopy was used to establish the wavelength of maximum absorbance for pure powder of artesunate and then the Beer's plot generated. This was validated and used to assay nine brands (X1-X9) of artesunate in Nigerian drug market. RESULTS: Distinctive ultraviolet absorption at 287 nm of pure sample of Artesunate in simulated intestinal fluid (SIF) afforded a simple, precise and the most reliable method for the analysis of nine different brands of Artesunate marketed in Nigeria. SIF does not have any appreciable absorption in the ultraviolet region. This simple method yielded a Beer's plot for Artesunate with high correlation (R2) of 0.9972 +/- 0.00016 and was reproducible. The Beer's plot was obeyed in concentration range of 10-200 mg%. The limits of detection (sensitivity) and quantitation were found to be 0.471 mg/ml and 1.27 mg/ml respectively. The results showed that only four out of the nine brands assayed had deviations from label claims that were within acceptable limits. INTERPRETATION & CONCLUSION: Based on these convincing data, simple ultraviolet spectroscopy at 287 nm could be used to assay artesunate in formulations.

In vitro bioequivalence study of nine brands of artesunate tablets marketed in Nigeria.

BACKGROUND & OBJECTIVES: The availability of numerous brands of artesunate in our drug market today places clinicians and pharmacists in a difficult situation of choice of a suitable brand or the possibility of alternative use. The aim of the present study was to predict the bioequivalence of nine brands of artesunate tablets marketed in Nigeria using in vitro tests. METHODS: The in vitro dissolution study was carried out on the nine brands of artesunate tablets using the basket method according to US Pharmacopoeia (USP) guidelines. Other general quality assessment tests like hardness and disintegration time were also determined. RESULTS: All the brands tested passed the British Pharmacopoeia (BP) standard for disintegration time. Only AT2, AT4, AT6 and AT9 passed the standard for hardness. There were significant differences in the dissolution profiles of the nine brands. All the brands except AT1, however, released >70% of artesunate within 30 min. Four of the brands AT5, AT6, AT7 and AT8 exhibited >90% dissolution in <10 min. The other brands AT1, AT2, AT3, AT4 and AT9 (innovator brand) have calculated similarity factors of 23.8, 59.8, 50, 54.8 and 100. INTERPRETATION & CONCLUSION: Based on the in vitro tests, AT5, AT6, AT7 and AT8 are considered bioequivalent and interchangeable, while AT2, AT3 and AT4 are considered bioequivalent and interchangeable with the innovator brand (AT9). AT1 has very low dissolution rate, which will likely result in poor bioavailability. The results show the need for constant monitoring of new brands of artesunate introduced into the drug market to ascertain bioequivalence and conformity with pharmacopoeia standards.

In vitro interaction between caffeine and some penicillin antibiotics against Staphylococcus aureus

Purpose: The aim of this study is to evaluate the in vitro interaction of some penicillins (amoxicillin; ampicillin and benzylpenicillin) and caffeine against Staphylococcus aureus. Method: The interaction between the penicillins and caffeine was studied using the Overlay Inoculum Susceptibility Disc (OLISD) method. Minimum inhibitory concentrations (MIC) of the drugs were determined separately and in combination with caffeine (5 and 10 mg/ml). Result: At 5 and 10 mg/ml; caffeine decreased the MIC of amoxicillin by 22 and 25 times respectively; while that of ampicillin was decreased by 6 and 8 times. The MIC of benzylpenicillin against Staphylococcus aureus was; however; increased by 59 and 40 times at caffeine concentrations of 5 and 10 mg/ml respectively. The inhibition zone diameter increment above 19(index of synergism in OLISD method) was recorded only for amoxicillin at amoxicillin concentrations of 7.81; 15.3; 31.25 and 62.5 mg/ml. Conclusion: The results of this study revealed that the concomitant use of caffeine and the studied antibiotics may potentiate the antibacterial effect of amoxicillin against Staphylococcus aureus; decrease that of benzylpenicillin and has virtually no effect on that of ampicillin. This implies that the intake of caffeine in form of analgesic combination or as tea; coffee; beverages or from other food sources may affect the effectiveness of a co-administered amoxicillin and bezylpenicillin

Haematotoxic evaluation of crude cannabis resin in rats

After chronic administration of crude Cannabisresin (CCR); (20 mg/kg and 40 mg/kg) to Spraque-Dawley albino rats for 21 days; the changes in various haematological indices such as packed cell volume (PVC); total leukocyte count; differential leukocyte count; red blood cell (RBC) count; absolute lymphocyte count; monocyte count; neutrophils and eosinophil counts were evaluated. The results show that the haematological indices such as erythrocytic and leucocytic counts were not significantly (P 0.05) affected by the treatment with the crude cannabinoid resin treated animal groups for the first two weeks of treatment. However in the third week; results showed significant increases (P 0.05) in the above mentioned indices while eosinophils disappeared from the blood of treated groups. It can be concluded from this study that chronic administration of CCR at high doses (above 20mg/Kg) to rats has slight haematotoxic potentials

An in vitro evaluation of antimicrobial interaction between glycine and some penicillins using the decimal assay for additivity (daa) method

The decimal assay for additivity (DAA) method was used to evaluate the in vitro interaction of glycine (Gly) with penicillin G (Pen G); cloxacillin (Clox) and ampicillin (Amp) against a clinical isolate of Staphylococcus aureus. In the interaction between Pen G/glycine with biological equivalent factor (BEF) 5 mg/62 mg; the decimal combination of 4 parts Pen G and 6 parts glycine showed amtagpmos; wjo;e ptjers sjpwed addotive effect In the interaction between Clox/glycine with BEF 1.26 og/62.5 mg ony 7:3 combination gave a synergistic effect. Others showed antagonism. In Amp/glycine combination with BEF; 1.74 og/62.5 mg; the decimal combinations of 4:6 gave additive effect; 9:1 gave synergistic effect while 7:3 combinaiton gave indifferent effect