Browsing by Author "Belete, Anteneh(Dr.)"

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    Evaluation of Cactus (Opuntia stricta) Mucilage as Sustained Release Excipient in Diclofenac Sodium Matrix Tablet Formulation
    (Addis Ababa Universty, 2018-12) Zenebe, Elias; Belete, Anteneh(Dr.)
    Nowadays, plant derived polymers have received increasing attention due to their diverse pharmaceutical applications in controlled drug delivery. Among these natural polymers, mucilages and gums are versatile excipients for pharmaceutical formulations. The main objective of the present study was to evaluate cactus (Opuntia stricta) mucilage as a matrix forming polymer for sustained release tablet formulations of diclofenac sodium. In this study, mucilage from cactus cladode was extracted by using distilled water as extracting solvent and ethanol as mucilage precipitant. The mucilage powder was characterized for physical properties. A 1% w/v solution of the mucilage in water gave a pH of 6.40, which shows low irritability potential in uncoated tablets. The powder was fairly flowing on the funnel, showing the need of other compressible excipient and granulation to make it better flowable. The Kawakita constants of compressibility and cohesiveness showed that the powder is compressible and cohesive. The solubility and swelling power of the Opuntia stricta were generally low at low temperature (20 °C), but increase significantly at higher temperature (85 °C) (p < 0.05). Percent moisture sorption ranged from 7.61% at 15% and 79.9% at 100% RH. On viscosity test, the mucilage showed pseudo-plastic property. The granules prepared with water as granulating solvent showed excellent flow property. The formulated matrix tablets were found to have good uniformity of weight. The tablets of different batches of directly compressed formulations were found to possess acceptable hardness within the range of 76.23 ± 0.24 to 80.51 ± 0.81. Crushing strength of wet granulated formulations was higher than the directly compressed formulations. The in vitro dissolution study demonstrated that both directly compressed and wet granulated formulations using Opuntia stricta mucilage effectively sustained diclofenac release for more than 12 h, even at low concentration, 10 %. However, granulation showed a better matrix for sustained release of drug from the tablets. All the formulations showed good linearity with respect to Korsmeyer-Peppas equation with 0.45 ≤ n ≤ 0.89 indicating that, non Fickian diffusion was the predominant mechanism of drug release from these formulations. So, Opuntia stricta mucilage can be used as alternative pharmaceutical excipient in the formulation and manufacture of sustained release matrix tablets.
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    Formulation, optimization and in vitro evaluation of fast disintegrating tablets of salbutamol sulphate
    (Addis Ababa Universty, 2018-03) Ejeta, Fikadu; Belete, Anteneh(Dr.)
    Obstructive respiratory disorders include asthma and chronic obstructive pulmonary disorders characterized by airflow limitation. Salbutamol sulphate is widely used drug for the treatment of chronic obstructive airway diseases. Oral administration of SBS is complicated due to sore throat conditions, the patient experiences difficulty in swallowing a conventional tablet dosage form and more difficult to use inhalation devices effectively owing to advanced age and the presence of other comorbidities. Moreover, aerosol drug delivery needs inhalation technique and difficulty of swallowing conventional tablet dosage forms decreases patient compliance. This study provides FDTs of SBS formulation with lower disintegration times and good mechanical strength for an immediate release with rapid onset of action and better patient acceptance. Formulation factors affecting the response variables (ammonium bicarbonate, crospovidone and microcrystalline cellulose to mannitol ratio (MCC/MNTL) were selected based on literature review and preliminary studies. Consequently, the levels of ammonium bicarbonate (subliming agent), levels of crospovidone (superdisintegrant) and MCC/MNTL (direct compression diluents) were considered. Ammonium bicarbonate level was fixed at 5% because of its esthetic impacts on tablets physical appearance. Central composite design was employed as study design to study and optimize the effect of formulation variables (concentration of crospovidone and MCC/MNTL) on tablet disintegration time, friability, hardness and wetting time. Accordingly, FDTs of SBS were prepared by sublimation technique with incorporation of superdisintegrant; and characterized for different tablet properties. Formulation (F6) containing 9.24% crospovidone, 1.25:1 MCC/MNTL and 5% ammonium bicarbonate showed the shortest disintegration time (12 ± 1.53 sec) and lowest wetting time (11 ± 1.00 sec) and; formulation (F8) containing 5% crospovidone, 2.31 : 1 MCC/MNTL and 5% ammonium bicarbonate had the largest crushing strength (7.88kg/cm2) and lowest friability (0.17%). These properties could be due to the disintegrant and binding properties of crospovidone and MCC respectively. All of the formulations released 75% of the label claim within 20 min. Accordingly, ANOVA and lack of fit test obtained by Design-Expert illustrated that selected independent variables had significant effect on the response variables and excellent correlation were observed between actual and predicted values. Simultaneous optimization of the responses with desired attributes indicated disintegration time 14.2 sec, hardness 7kg/cm2 , friability 0.30 IX | Page and wetting time 13.2 sec at 7.82% crospovidone and 1.56: 1 MCC/MNTL (at 70%) as optimum formulation. The validity of an optimum formulation was further confirmed by the low magnitude of percent prediction error. The optimized formulation was characterized for powder properties, tablets physicochemical properties and tablets morphology. The study showed that free flowing powder, robust prediction (between the actual and predicted values) and porous tablets. FDTs of SBS with lower DTs and good mechanical strength which is suitable for patients with obstructive respiratory disorders was successfully developed.