Larvicidal activities of five Kotschya species against Culex quinquefasciatus Say (Culicidae: Diptera)

Resistance of mosquito vectors to the commonly used chemical insecticides is posing threats to human health. It is becoming necessary to identify safe, eco-friendly and effective alternative sources of larvicides in order to reduce mosquito menace. HPLC profiling of the chemical constituents in the stem and root bark ethanol extracts had similar pattern of chemical constituents except for K. aeschynomenoides which indicated to have large quantity of polar compounds compared to others. In this study, the ethanolic extracts and powders of five Kotschya species were tested against Culex quinquefasciatus Say. Chemical profiling of the stem and root bark ethanol extracts from K. speciosa, K. thymodora, K. platyphylla, K. aeschynomenoides and K. strigosa did not show any major differences in terms of their chemical composition. At 0.5 mg/ml, the root and stem ethanol extracts from K. speciosa, K. thymodora and K. strigosa exhibited high larvicidal activity (≥ 70%) on the 8th day post treatment. Stem powder of K. thymodora and root powder of K. speciosa and K. strigosa had activity comparable to their respective extracts at 0.2% w/v and 0.4% w/v at the same exposure time. This suggests that Kotschya species contain same or related compounds in varying quantities that are responsible for larvicidal activity.Keywords: Fabaceae, Kotschya strigosa, K. speciosa, K. thymodora, K. platyphylla, K. aeschynomenoides, Larvicidal, Culex quinquefasciatu

Formulation development and optimization of taste masked generic fast dissolving zinc sulphate tablets

Zinc sulphate tablets are indicated for the management of diarrhoea in children regardless of the cause. In Tanzania, there is only one pharmaceutical industry manufacturing zinc sulphate tablets and only 44% of children in need of zincsulphate tablets get access to them. Fast-disintegrating tablets of zinc sulphate were prepared by direct-compression method after incorporating the superdisintegrant polyvinyl pyrollidine cross-linked. Different types of experiments and evaluation parameters for tablets were assessed. Design expert software version 7 was used to optimize the formulation. Tablets containing polyvinyl pyrollidine cross-linked showed excellent disintegration time, friability and hardness compared to formulations containing other superdisintegrants. Tablets with 30mg/60mg sodium saccharin/strawberry had a palatable taste. Assay was within 95% to 105%, disintegration time was less than 60 seconds, and hardness was between 3.0 kg/cm2 to 4.0 kg/cm2, which comply with official US Pharmacopeia requirements. Therefore, a taste masked generic formulation of 20 mg zinc sulphate fast dissolving tablets with accurate dose and palatable taste was successfully developed and optimized.Keywords: Zinc sulphate monohydrate, Fast disintegrating tablets, Disintegration tim

Modeling solutions to Tanzania's physician workforce challenge.

BACKGROUND:There is a great need for physicians in Tanzania. In 2012, there were approximately 0.31 physicians per 10,000 individuals nationwide, with a lower ratio in the rural areas, where the majority of the population resides. In response, universities across Tanzania have greatly increased the enrollment of medical students. Yet evidence suggests high attrition of medical graduates to other professions and emigration from rural areas where they are most needed. OBJECTIVE:To estimate the future number of physicians practicing in Tanzania and the potential impact of interventions to improve retention, we built a model that tracks medical students from enrollment through clinical practice, from 1990 to 2025. DESIGN:We designed a Markov process with 92 potential states capturing the movement of 25,000 medical students and physicians from medical training through employment. Work possibilities included clinical practice (divided into rural or urban, public or private), non-clinical work, and emigration. We populated and calibrated the model using a national 2005/2006 physician mapping survey, as well as graduation records, graduate tracking surveys, and other available data. RESULTS:The model projects massive losses to clinical practice between 2016 and 2025, especially in rural areas. Approximately 56% of all medical school students enrolled between 2011 and 2020 will not be practicing medicine in Tanzania in 2025. Even with these losses, the model forecasts an increase in the physician-to-population ratio to 1.4 per 10,000 by 2025. Increasing the absorption of recent graduates into the public sector and/or developing a rural training track would ameliorate physician attrition in the most underserved areas. CONCLUSIONS:Tanzania is making significant investments in the training of physicians. Without linking these doctors to employment and ensuring their retention, the majority of this investment in medical education will be jeopardized

A quantitative near infrared spectroscopy model for the assay of efavirenz in tablets

Near-infrared-spectroscopy combined with multivariate data analysis represents the most recent and efficient technology in analytical chemistry. The objective of this study was to utilize near infrared spectroscopy as an adapted technology for the quantitative assay of efavirenz. The study developed and validated a quantitative model for estimating the amount of efavirenz in efavirenz uncoated tablets. The quantification was based on the partial least squares algorithm and constructed by cross-validation. A UV spectrophotometric procedure was used as the reference method. Different pre-processing methods were employed in the development of calibration models. The best calibration model was that using partial least squares as the regression algorithm in association with Multiplicative Scattering Correction as the spectrum pre-processing method. The model estimators were: coefficient of determination (R²) 0.9815, standard error of cross validation 2.0346 and a factor of 5. The chosen model correlated well with the prediction results in accordance with the Mahalabinos distance limits. The developed NIR method allows the estimation of the amount of efavirenz in tablets without sample preparation thus proving to be a simple, fast and suitable method for the quantitative assay of efavirenz in uncoated tablets. Hence, NIR coupled with chemometric methods can be used for on-line, in-line or at-line monitoring of the manufacturing process and are helpful in achieving the goals of Process Analytical Technology.Keywords: Near Infrared Spectroscopy, chemometrics, multivariate data analysis, efavirenz, Partial Least Squares, cross validatio

A Thin Layer Chromatography Densitometric Method for Assay of Folic Acid in Tablets

A High Performance Thin Layer Chromatography (HPTLC) method for analysis offolic acid was developed and validated according to ICH and USP guidelines. Thedeveloped method was used for simultaneous qualitative and quantitative analysisof folic acid in tablets. The method was developed using an environmentallyfriendly mobile phase containing ethyl acetate:methanol:ammonia solution(15:15:0.5 v/v/v) on pre-coated HPTLC silica gel 60 F254 glass plates at a detectionwavelength of 280 nm using reflectance absorbance and saturation time of 25 min.Densitometric analysis showed two folic acid products being retained at Rf of 0.27and 0.67 and the area was taken as the sum of the two. The method was specific andno interferences were observed between folic acid peaks and that of the excipients.The calibration curve of folic acid was constructed using both linear andpolynomial regression function in the range of 317.19–761.25 ng/spot both withregression coefficient, r2 of 0.998. The accuracy at nominal concentration of folicacid was found to be 101.05%, % rsd, repeatability and intermediate precisionwere found to be 1.79% and 1.93 respectively. The developed method is thus simple,accurate, and cost effective with good precision and repeatability for the assay offolic acid in tablets which will be particularly useful in resource constrainedcountries.Key words: High performance thin layer chromatography, densitometry, validation, folic aci

Factors influencing adherence to antiretroviral therapy among people living with HIV in an urban and rural setting, Tanzania

Adherence is one of the most crucial determinants of treatment response to antiretroviral therapy (ART). An analytical cross-sectional study was conducted in 24 Care and Treatment Centres (CTC) in Dar es Salaam and Iringa regions in Tanzania. Data was collected using questionnaire and appointments records. A total of 943 patients attending at the care and treatment sites in Dar es Salaam and Iringa were recruited. Adherence based on keeping appointments and on four days recall was 65% and 70%, respectively. Adherence based on taking ART more than 95% of the time in one month was 83%. Satisfaction with health services, having treatment support, having knowledge on the use of ART, early presentation to CTC, and being on ART for more than one year, were associated with good adherence. Being in the urban region, using traditional medicine, medicine side effects and alcohol consumption problems negatively associated with adherence to ART.Keywords: Adherence barriers, antiretroviral therapy, HIV, Tanzania, rural, urba

Stability indicating liquid chromatographic method for determination of lamivudine and tenofovir disoproxil fumarate in fixed dose combination formulations

This study describes the development and validation of a stability indicating high performance liquid chromatographic method for the analysis of lamivudine and tenofovir disoproxil fumarate and their degradants. The method uses a Reprosil®-pur basic C18 column (250 mm × 4.6 mm, 5 μm) maintained at 30°C, methanol and a mixture of buffers (2.3 g/L ammonium dihydrogen phosphate and 1.32 g/L of diammonium hydrogen phosphate, pH 3.9) for gradient elution at a flow rate of 1.0 mL/min, and UV detection at 270 nm. Good separation of lamivudine and tenofovir disoproxil fumarate and their potential impurities was achieved. The stability indicating ability of the developed method was validated by subjecting both active ingredients to hydrolytic and oxidative stress conditions and separating the degradation products from their respective intact drugs. The calibration curve was linear over the 80-120 μg/mL concentration range for both active ingredients with r2> 0.99. A recovery rate of 99.8 % for lamivudine and 99.3 % for tenofovir disoproxil fumarate confirmed the accuracy of the method for the simultaneous determination of both drugs in the fixed-dose combination.Keywords: Stability indicating liquid chromatography, lamivudine, tenofovir, validatio

Preformulation Studies for Generic Omeprazole Magnesium Enteric Coated Tablets

Preformulation is an important step in the rational formulation of an active pharmaceutical ingredient (API). Micromeritics properties: bulk density (BD) and tapped density (TD), compressibility index (Carr's index), Hauser's ratio (H), and sieve analysis were performed in order to determine the best excipients to be used in the formulation development of omeprazole magnesium enteric coated tablets. Results show that omeprazole magnesium has fair flow and compressibility properties (BD 0.4 g/mL, TD 0.485 g/mL, Carr's index 17.5%, Hauser's ratio 1.2, and sieve analysis time 5 minutes). There were no significant drug excipient interactions except change in colour in all three conditions in the mixture of omeprazole and aerosil 200. Moisture content loss on drying in all three conditions was not constant and the changes were attributed to surrounding environment during the test time. Changes in the absorption spectra were noted in the mixture of omeprazole and water aerosil only in the visible region of 350-2500 nm. Omeprazole magnesium alone and with all excipients showed no significant changes in omeprazole concentration for a 30-day period. Omeprazole magnesium formulation complies with USP standards with regards to the fineness, flowability, and compressibility of which other excipients can be used in the formulation

Comparing Patterns of Sexual Risk among Adolescent and Young\ud Women in a Mixed-method Study in Tanzania: Implications for\ud Adolescent Participation in HIV Prevention Trials

Despite the disproportionate impact of HIV on women, and adolescents in particular, those below age 18 years are underrepresented in HIV prevention trials due to ethical, safety and logistical concerns. This study examined and compared the sexual risk contexts of adolescent women aged 15 17 to young adult women aged 18 21 to determine whether adolescents exhibited similar risk profiles and the implications for their inclusion in future trials. We conducted a two-phase, mixed-method study to assess the opportunities and challenges of recruiting and retaining adolescents (aged 15 17) versus young women (18 21) in Tanzania. Phase I, community formative research (CFR), used serial in-depth interviews with 11 adolescent and 12 young adult women from a range of sexual risk contexts in preparation for a mock clinical trial (MCT). For Phase II, 135 HIV-negative, non-pregnant adolescents and young women were enrolled into a six-month MCT to assess and compare differences in sexual and reproductive health (SRH) outcomes, including risky sexual behaviour, incident pregnancy, sexually transmitted infections (STIs), reproductive tract infections (RTIs) and HIV. In both research phases, adolescents appeared to be at similar, if not higher, risk than their young adult counterparts. Adolescents reported earlier sexual debut, and similar numbers of lifetime partners, pregnancy and STI/RTI rates, yet had lower perceived risk. Married women in the CFR appeared at particular risk but were less represented in the MCT. In addition, adolescents were less likely than their older counterparts to have accessed HIV testing, obtained gynaecological exams or used protective technologies. Adolescent women under 18 are at risk of multiple negative SRH outcomes and they underuse preventive services. Their access to new technologies such as vaginal microbicides or pre-exposure prophylaxis (PrEP) may similarly be compromised unless greater effort is made to include them in clinical trial research