In vitro REGENERATION OF PIGEON PEA USING LEAF EXPLANTS

Pigeon pea ( Cajanus cajan (L.) Millsp.) is a drought tolerant pulse legume, mainly grown for grain in the semi-arid tropics, particularly in Africa. Pigeon pea production in countries like Kenya is faced with a number of challenges, particularly lack of high quality seeds. The objective of this study was to develop an in vitro regeneration system for pigeon pea varieties grown in Kenya, that is amenable to genetic transformation. In vitro regeneration of pigeon pea varieties, KAT 60/8 and ICEAP 00557, commonly grown in Kenya was achieved using leaf explants from in vitro grown seedlings, through callus initiation, followed by shoot and root induction. For callus initiation, MS media supplemented with 0.5-4 mg l-1 2, 4-D and TDZ separately were tested, and IBA at 0.1, 0.5 and 1 mg l-1 was tested for rooting of shoots. Embryogenic calli was obtained on MS containing 2, 4- D; whereas TDZ induced non-embryogenic callus alone or with shoots directly on explants. Indirect shoot regeneration frequency of 6.7 % was achieved using 1 mg l-1 2, 4-D-induced embryogenic callus obtained using KAT 60/8 explants. Whereas direct shoot regeneration frequencies of 20 and 16.7% were achieved using ICEAP 00557 and KAT 60/8 explants, using 0.5 mg l-1 and 2 mg l-1 TDZ, respectively. Optimum rooting was achieved using 0.5 mg l-1 IBA; and up to 92% rooted shoots were successfully established in soil after acclimatisation. Genotype and hormone concentrations had a significant (P<0.05) influence on callus, shoot and root induction. The protocol developed can be optimised for mass production and genetic transformation of KAT 60/8 variety.

In-vitro evaluation of the quality of Paracetamol and Co-trimoxazole tablets used in Malawi based on pharmacopoeial standards

Objectives This study was an in-vitro evaluation of different brands of paracetamol and cotrimoxazole tablets, used or found in Malawi, based on Pharmacopoeia standards, in order to ascertain the existence and extent of substandard medicines in Malawi and to give an overview of their distribution in the public and private sectors. Methodology A cross-sectional analytical study was conducted using 11 samples each of paracetamol and cotrimoxazole tablets. Stratified random sampling was used to collect samples. Samples were analyzed using HPLC and Spectrophometric methods as outlined in the BP-2007 and USP-32 at the National Drug Quality Control Laboratory (NDQCL)-Lilongwe (under Pharmacy Medicines and Poisons Board-PMPB) and Orient Pharma Co. Ltd of Taiwan. The results were analyzed using Epi Info. Results and discussion Fifty percent of samples (n=22) were not registered in the country by the PMPB as required by the PMP Act with the majority of those coming from public health facilities. All paracetamol and cotrimoxazole samples complied with identification tests using spectrophotometric and HPLC method. Overall, 27.3% of samples failed to meet the BP-2007 standards for Active Ingredient content, while 22.7% of the samples failed the Friability test. The results from Malawi are similar in magnitude to those within surrounding countries in Africa. Conclusion This pilot study provides objective evidence to show that substandard and unregistered paracetamol and cotrimoxazole are present and being used in Malawi, and thus posing a considerable hazard to public health in Malawi. PMPB, together with the Ministry of Health, must continue to develop a quality assurance system to ensure that medicines are randomly and routinely checked.

In vitro effects of erosive challenge on the surface properties of sealants

Aim: To assess in vitro the surface roughness (Ra), Vickers hardness (VHN) and surface morphology of resin and glass ionomer materials used for sealants after dynamic erosive challenge. Methods: Twenty specimens of each material were prepared and divided into experimental (erosive challenge) and control groups (n=10): Protect Riva (SDI), Opallis Flow (3M ESPE), Fluroshield (Dentsply), Filtek Z350 XT Flow (3M ESPE). The erosive challenge was performed 4 times per day (90 s) in cola drink and for 2 h in artificial saliva for 7 days. The control specimens were maintained in artificial saliva. Ra and VHN readings were performed before and after erosion. The percentage of hardness loss (%VHN) was obtained after erosion. The surface morphology was evaluated by scanning electron microscopy (SEM). The data were analyzed by ANOVA, Tukey and paired t tests (α=0.05). Results: After erosion and saliva immersion, there was an increase in Ra values for all groups and Riva group showed the highest Ra values. After erosive challenge, Riva and Filtek groups showed significant decrease in VHN values, but Filtek group showed the greatest %VHN. For all groups there was inorganic particle protrusion and matrix degradation after erosion visualized by SEM images. Conclusions: Erosive challenge affected the surface properties of all materials used as sealants, particularly in the Riva and Filtek groups.

In vitro study of interaction between quinine and Garcinia kola

Purpose: To investigate the interaction between quinine and Garcinia kola using an in vitro adsorption study. Methods: In vitro interaction between quinine and G. kola was conducted at 37 ± 0.1 °C. Adsorption of quinine (2.5 - 40 μg/ml) to 2.5 % w/v G. kola suspension was studied. Thereafter, quinine desorption process was investigated. The amount of quinine adsorbed and desorbed was quantified using HPLC. A Freundlich isotherm was constructed to describe the resulting data and percentage of quinine desorbed was determined from the desorption data. Results: An adsorption isotherm of the data gave a Freundlich constant (K) of 52.66 μg/g, with a slope of 0.69 indicating a high capacity and affinity of G. kola to adsorb quinine at a concentration smaller than 2.41 μg/g of G. kola. However the adsorptive capacity of G. kola for quinine at 37 ± 0.1 °C appears to be a saturable process as observed from the isotherm. Quinine desorption from G. kola peaked at 1 hour (37.51 %) and decreased to a constant amount (about 35 %) over the remaining sampling time. Conclusion: Quinine is adsorbed on G. kola in vitro. This suggests that concurrent administration of quinine and G. kola should be avoided, to prevent potential drug interaction and decreased drug bioavailability.