acta 2_2015

358 OLADAPO A. ADETUNJI et al.In the present work, a 2 4 full factorial designhas been used to study the individual and interactioneffects of nature of binder (denoted by N), concentrationof binder (denoted by C), relative density(denoted by D) and tableting technique (denoted byM) on the disintegration time, tensile strength, brittlefracture index and mucoadhesion time of thetablets.Ibuprofen has been chosen for this studybecause of its poor compressibility and hence itrequires a binder among other excipients to formtablets of satisfactory tensile strength.MATERIALS AND METHODSThe materials used were: ibuprofen powderBP, (BDH Chemicals Ltd., Poole, U.K.), lactose BP,magnesium stearate BP, and hydroxypropylcellulose(HPC) (Aqualon, Hercules Incorporated, USA),all supplied by Bond Pharmaceuticals Ltd., Nigeria.Entandophragma angolense gum (family:Meliaceae) was obtained from the incised trunk ofthe tree available within the complex of the ForestryResearch Institute of Nigeria, Jericho, Ibadan,Nigeria.Collection and purification of gum extractThe brown colored gum, collected as earlymorning exudates from previous incisions made onthe trunk of Entandophragma angolense tree wasweighed, allowed to dry and then thoroughlywashed in chloroform/water (D/S) to remove associatedearth particles. The precipitated gum was filtered,washed with diethyl ether and then dried in ahot air oven at a temperature of 40 O C for 24 h. Thedried gum was pulverized and passed through anumber 60 mesh sieve (250 µm) (10, 16). The percentageweight of the purified and dried gumobtained from the exudates was then calculated. Thedried gum (0.005 g) was dissolved in water, mountedon the microscope and observed for the presenceof any foreign organic matter to determine the levelof gum purity (17).Fourier Transform Infrared (FTIR) analysisSpectra were obtained for the Entandophragmaangolense gum, gelatin or HPC and ibuprofen usinga Nicolet Magna-IR, 560 spectrometer.A quantity (5 mg) of each of the completelydried powdered samples was weighed and then dispersedin 200 mg potassium bromide (pellet procedure).Signal averages were obtained at a resolutionof 4 cm -1 .UV analysisVarious mixtures of Entandophragmaangolense gum or hydroxypropylcellulose and oribuprofen were scanned in the wavelength range190-300 nm. The maxima at 265 nm and 221 nmwere monitored for wavelength shifts on a modelDU-7400 spectrophotometer (Beckman, Fullerton,CA).Preparation of granulesBatches (250 g) of a basic formulation comprisingof ibuprofen, lactose, and Entandophragmaangolense gum (or hydroxypropylcellulose), at aratio of 6 : 3 : 1, respectively, were dry mixed for 5min in a planetary mixer (Model A120, HobartManufacturing Co., U.K.) and moistened withappropriate amount of paste of the binding agentEntandophragma angolense gum (or hydroxypropylcellulose)to produce samples containing differentconcentrations of the binder.Massing was continued for about 5 min and thewet masses were granulated by passing them manuallythrough a no. 12 mesh sieve (1,400 µm). Thegranules were dried in hot air oven for 16 h at 60 O C.The dried granules were then re-sieved through anumber 16 mesh sieve (1,000 µm), before they werestored in air-tight containers.Figure 1. Rotating cylinder apparatus for mucoadhesion studiesPreparation of tabletsWet granulationGranule size fractions (500ñ1,000 µm) wereused to prepare the tablets (400 ± 5 mg) using aCarver hydraulic hand press (model C, Carver Inc,Menomonee Falls, Wisconsin, USA), equipped witha 10.5 mm flat faced punch and die set lubricatedwith a 1% dispersion of magnesium stearate in acetoneprior to compression.Different compression pressures wereemployed to obtain different relative densities, ρ r ,