Augustine O. Okhamafe

Physicochemical properties of maize cob cellulose powders reconstituted from ionic liquid solution

Suitable α-cellulose and cellulose II powders for use in the pharmaceutical industry can be derived from maize cob. α-Cellulose was extracted from an agricultural residue (maize cobs) using a non-dissolving method based on inorganic substances. Modification of this α-cellulose was carried out by its dissolution in the ionic liquid 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), and subsequent regeneration by addition of either water or acetone at room temperature, or of boiling water. X-ray diffraction and infrared spectroscopy results showed that the regenerated celluloses had lower crystallinity, and proved that the treatment with [C4mim]Cl led to the conversion of the crystalline structure of α-cellulose from cellulose I to cellulose II. Thermogravimetric analysis and differential scanning calorimetry data showed quite similar thermal behavior for all cellulose samples, although with somewhat lower stability for the regenerated celluloses, as expected. The comparison of physicochemical properties of the regenerated celluloses and the native cellulose mainly suggests that the regenerated ones might have better flow properties. For some of the characterizations carried out, it was generally observed that the sample regenerated with boiling water had more similar characteristics to the α-cellulose sample, evidencing an influence of the regeneration strategy on the resulting powder after the ionic liquid treatment.

Modulation of protein release from chitosan-alginate microcapsules using the pH-sensitive polymer hydroxypropyl methylcellulose acetate succinate

The release characteristics of protein from chitosan-alginate microcapsules prepared using an electrostatic droplet generator were evaluated. The release studies were undertaken in-vitro in simulated gastrointestinal fluids covering the pH range 1.2-8. Chitosan-alginate microcapsules showed unsatisfactory release properties, losing 94% of the encapsulated proteins (bovine serum albumin) over a 24 h period at pH 1.2. Incorporation of a pH-sensitive polymer, hydroxypropyl methylcellulose acetate succinate (HPMCAS), in the microcapsules, by coating the capsule membrane as well as blending with the capsule core polymer in varying ratios, produced significant changes in the release profiles of the microcapsules. At pH 1.2, the modified microcapsules retained up to 60% of the encapsulated protein after 24 h. The results obtained highlight the potential of HPMCAS as a release-modifier in chitosan-alginate microcapsules.

A survey of knowledge, attitude and practice of malaria management among pregnant women from two health care facilities in Nigeria

Background. Malaria remains one of the most important causes of maternal and child morbidity and mortality in sub‐Saharan Africa, despite the availability of effective interventions. The objective of this study was to assess the knowledge, attitude and practice of malaria management among pregnant women attending antenatal clinics in Nigeria. Methods. A cross‐sectional study was undertaken on a sample of 867 pregnant women attending antenatal clinics in 2 health care facilities in Edo State, Nigeria, using a self‐administered questionnaire. Results. Of the respondents, 87% said that they had undergone at least 1 episode of malaria during their current pregnancy. Most respondents (89%) attributed malaria to bites from infected mosquitoes, while 75% consider malaria an important health risk during pregnancy. However, knowledge of the consequences of malaria during pregnancy was poor, especially the risk posed to the fetus. Overall, the mean knowledge score on a scale of ‘0–7’ was 3.5 (median 4.0). Respondents had poor belief in the effectiveness and use of insecticide‐treated bed nets and intermittent preventive therapy, in preventing malaria during pregnancy. Conclusions. This study has revealed that malaria is perceived as a common health problem among pregnant women attending these 2 health care facilities, and that knowledge, attitude and practice of its management is poor. Efforts should be made to improve anti‐malarial intervention during pregnancy, to ensure that the goals of the Roll Back Malaria Initiative are achieved in Nigeria.

Response of Trypanosoma brucei brucei-induced anaemia to a commercial herbal preparation

®is a herbal preparation made from three medicinal herbs (Parquetina nigrescens, Sorghum bicolor and Harungana madagascariensis). It has been reported to have been successfully used in the treatment of anaemia in humans. A study was therefore carried out to determine the effect of the preparation on packed cell volume (PCV) and haemoglobin (Hb) concentrations in anaemic rabbits. The PCV and Hb concentrations of healthy rabbits infected with Trypanosoma brucei brucei were monitored for 49 days. T. b. brucei produced a significant reduction in PCV and Hb concentrations in all infected rabbits when compared with the controls (p<0.05). These hematological parameters were restored to normal levels in the anaemic rabbits by the herbal preparation. The anaemic rabbits not treated with the herbal preparation presented with a progressive decline in their PCV and Hb concentrations and majority of them died before the end of the study. Healthy rabbits that received daily doses of the herbal preparation showed gradual elevation in PCV and Hb concentrations which were maintained within normal range. Jubi Formula ® can restore the PCV and Hb concentrations in anaemic conditions and is a potential substitute for blood transfusion. However, further studies are needed to investigate the potentials of the herbal preparation in reversing anaemia.

Physicochemical, spectroscopic and thermal properties of microcrystalline cellulose derived from corn cobs

BackgroundLow-cost and suitable microcrystalline cellulose powders for use in the pharmaceutical industry can be derived from agricultural residues. Most commercial microcrystalline cellulose powders are produced from dissolving pulp obtained from expensive hard woods using concentrated acids. α-Cellulose was extracted from an agricultural residue (corn cob) using a non-dissolving method. The spectroscopic, thermal and physicochemical properties of the derived α-cellulose and microcrystalline cellulose powders were compared with Avicel® PH 101 (Fluka, New South Wales, Australia), a commercial brand of microcrystalline cellulose (MCCA), using standard methods.ResultsX-ray diffraction showed that the microcrystalline cellulose samples obtained from maize cobs had diffraction pattern characteristics of both cellulose I and cellulose II, whereas MCCA had that of cellulose I; however, all the microcrystalline cellulose samples had similar crystallinity index (CI) values. Infrared spectroscopy results showed that the microcrystalline cellulose samples had comparable CI values and molecular structure. Thermogravimetric analysis and differential scanning calorimetry data showed quite similar thermal behaviour for all cellulose samples. Comparison of physicochemical properties of the microcrystalline cellulose powders obtained from maize cob and MCCA mainly suggests that all the celluloses have similar flow and compression properties.ConclusionsFor almost all of the characterizations carried out, it was observed that the microcrystalline cellulose powders obtained from corn cob had similar characteristics to the MCCA, showing that it can be a good low-cost alternative to the expensive commercial brand.

Pharmacokinetic interactions of norfloxacin with some metallic medicinal agents

Abstract The influence of some metallic therapeutic compounds on the pharmacokinetics of orally administered norfloxacin in healthy human volunteers has been examined. The in vitro availability of norfloxacin in dissolution media containing these metallic compounds was also studied. Peak saliva concentration (C max ) and bioavailability (AUC 0–9 ) of norfloxacin were reduced by approx. 35-fold, 3–5 fold and 40–50% when co-administered with ferrous sulphate, magnesium trisilicate and potassium citrate, respectively. Concomitant administration with sodium bicarbonate and aluminium hydroxide did not significantly modify the pharmacokinetics of norfloxacin but calcium carbonate reduced its bioavailability by 47%. The absorption and elimination rates of norfloxacin were not affected by the metallic compounds, except potassium citrate which decreased both the absorption and elimination of the drug. There was some degree of correlation between the saliva, urine and in vitro results. Based on the data obtained, it was evident that norfloxacin formed unabsorbable and/or antibacterially inactive/less active complexes with Fe 2+ , Mg 2+ and Al 3+ . Complex formation, adsorption and pH-mediated effects were proposed as factors responsible for the alteration of the pharmacokinetics of norfloxacin by the co-administered agents. There was no clearly discernible link between the valency of the metal ion and its influence on norfloxacin pharmacokinetics.

A survey of anti-malarial activity during pregnancy, and children's malaria care-seeking behaviour in two Nigerian rural communities

This study investigated anti-malarial prophylaxis during pregnancy and childrens malaria care-seeking behaviour by mothers with children 5 y of age and below drawn from 2 rural communities in southern Nigeria. Findings showed that 37% of mothers said they had used anti-malarial prophylaxis (chloroquine, 50%) during pregnancy, while only 30% of them had bed net (untreated) at home, with 44% of the bed net damaged. Over half (59%) of the respondents reported that their children had had fever/malaria in the forthnight recall period, and a majority of them (44%) were treated in medicine shops. Injections accounted for 33% of the medications received by them. Of the 74% of children who were given treatment, there were delays of 2 or more d in seeking care for a quarter of them. Only 21% of the mothers attributed malaria to bites from infected mosquitoes, despite the high prevalence of childhood malaria. Low coverage of anti-malarial intervention during pregnancy and inappropriate childrens malaria care-seeking behaviour has been identified. An appropriate mechanism for delivery of insecticide-treated bed nets in addition to educational interventions is recommended in order to reduce the burden of malaria among pregnant women and children in these communities.

Prevalence of malaria during pregnancy and antimalarial intervention in an urban secondary health care facility in Southern Nigeria.

Objective: To investigate the prevalence of malaria during pregnancy and antimalarial interventions in an urban secondary health care facility. Subjects and Methods: Of 432 pregnant women who delivered or were attending an antenatal clinic in a secondary health care facility in Benin City, Nigeria, 199 were recruited for the study. Demographic data were obtained from the pregnant women at delivery, and maternal peripheral, placental, and cord blood samples were collected for microscopy. Among the antenatal clinic attendees, a questionnaire was used to assess their antimalarial preventive measures. Results: Of the 199 pregnant women, 60 (30%) reported that they had had malaria during the preceding 3 months, and a majority of them (85%) used chloroquine. Almost all reported the drug was efficacious (98%) and well tolerated (80%). Only 18 (13%), 14 (10%), and 2 (1%) of the women had positive maternal peripheral, placental, and cord blood parasitaemia, respectively. The geometric mean (± SD) numbers of malaria parasites per microliter were 636.06 ± 1,450.11 in peripheral blood, 4,250.36 ± 13,866.01 in placental blood, and 59.50 ± 27.58 in umbilical cord blood. Only 31 (12%) and 13 (5%) of antenatal women believed in the efficacy of insecticide-treated bed nets or sulphadoxine/pyrimethamine-based intermittent preventive therapy as antimalarial preventive measures, respectively, while 23 (9%) and 31 (12%), respectively, reported they currently use them. Conclusions: Despite the common occurrence of malaria during pregnancy, there was a limited knowledge and use of the recommended antimalarial interventions by pregnant women attending the antenatal clinic of this health care facility. There is, therefore, an urgent need to increase the implementation of antimalarial interventions during pregnancy.

Evaluation of the Pharmaceutical Quality of Some Quinine Preparations Sold in Nigeria

Objective: The purpose of this study was to determine the pharmaceutical quality of quinine preparations sold in Nigerian markets. Materials and Methods: The organoleptic and physicochemical properties of quinine tablets, as well as oral liquids and parenteral quinine preparations, were assessed according to British Pharmacopoeia (BP) and unofficial standards as recommended by the manufacturers. Results:Of the 6 brands of tablets assessed, 4 passed the uniformity of content test and 5 the disintegration test, but only 2 the dissolution test. The pH of 2 of the 6 brands of oral liquid preparations met BP standards, while only 1 oral liquid met the BP standard for percentage content. The assay further demonstrated that 4 brands of the parenteral preparations met BP standards for quinine content. All the parenteral preparations were found to be sterile. Conclusion: Quinine preparations sold in Nigeria varied considerably in their pharmaceutical quality. A strict check of the quality of brands of quinine by regulatory agencies and distributors before they are sold to the public is therefore recommended.

Plasmodium falciparum malaria resistance to chloroquine in five communities in Southern Nigeria

Chloroquine is still a first-line antimalarial drug in uncomplicated falciparum malaria. Increasing resistance to chloroquine has been reported in many parts of Nigeria. Clinical and parasitological responses and classes of resistance to chloroquine in falciparum malaria in five communities in Delta region, southern Nigeria were assessed. Chloroquine was administered to 218 patients with uncomplicated P. falciparum malaria. The levels of parasitemia, clinical response and classes of resistance were monitored for 7 days. High levels of therapeutic failures of chloroquine in P. falciparum malaria were recorded in the region. The frequencies of clinical and parasitological failure of chloroquine were 25.7% and 55%, respectively. These frequencies were significantly lower in children below 5 years than older people. R2 and R3 resistance occurred in 37.2% and 17.4% of the patients, respectively. The therapeutic failure of chloroquine was not gender dependent. We conclude that chloroquine is still effective in the treatment of uncomplicated P. falciparum malaria in some communities in Delta region of Nigeria. However, resistance to chloroquine is likely. These results may be used as an important indicator of the significant level of therapeutic failure of uncomplicated P. falciparum malaria to chloroquine in Nigeria. Keywords: Chloroquine, falciparum malaria, resistance, clinical failure, parasitological failure. African Journal of Biotechnology Vol.2(10) 2003: 384-389