L-carnitine-L-tartrate, a non-essential amino acid, is hygroscopic. This causes a problem in tablet production due to pronounced adhesion of tablets to punches. A 3 3 full factorial design was adopted to suggest a tablet formulation. Three adsorbents were suggested (Aerosil 200, Aerosil R972, talc) to reduce stickiness at three concentrations (1, 3 and 5 %), and three fillers (mannitol, Avicel PH 101, Dibasic calcium phosphate) were chosen to prepare 27 formulations. Micromeritic properties of formulations were studied, and tablets were prepared by wet granulation. Absence of picking, sticking or capping, recording of sufficient hardness, acceptable friability and tablet ejection force indicated formulation success. The resulting formulation prepared using Avicel PH 101 and 1 % Aerosil 200 was submitted to further investigation in order to choose the most suitable compression conditions using a 3 3 full factorial design. Variables included compression force, tableting rate and magnesium stearate (lubricant) concentration. The formulation prepared at compression force of 25 kN, using 2 % magnesium stearate, at a production rate of 30 tablets/ minute, was found to be the most appropriate scale up candidate.Keywords: L-carnitine-L-tartrate, adsorbent, scale-up, compression force, ejection force, hygroscopicCarnitine is a non-essential amino acid derivative and a cofactor of fatty acid metabolism in the heart, liver and skeletal muscle (1). It was designated vitamin Bt but is not an officially recognized vitamin (2). It is found primarily in animal products such as meat (principally red meat), fish, poultry (2). In humans, the liver, brain and kidney synthesize carnitine (3, 4). Carnitine is an endogenous mitochondrial membrane compound (5) and its deficiency results in disordered membrane transport (1, 2). L-carnitine is a ((R)-(3-carboxy-2-hydroxypropyl) trimethylammonium hydroxide inner salt) (6). It occurs in two distinct stereoisomers, namely, L-carnitine (naturally occurring carnitine, which is biologically active) and D-carnitine (synthetic carnitine, which is biologically inactive) (7). L-carnitine is a white or almost white crystalline powder or comes in the form of colorless crystals, hygroscopic and freely soluble in water. It is soluble in warm ethanol (96 %) and practically insoluble in acetone, ether and benzene (8, 9). L-carnitine was formulated easily into liquid preparations such as an oral solution and i.v. injection. Due to its hygroscopicity, its formulation into capsules is not preferred (10), as the stability of the capsule shell is affected (11).Formulation of L-carnitine-L-tartrate into tablets offers many advantages over hard gelatin capsules. Tablets can contain a relatively high dose of L-carnitine-L-tartrate, mainly 485.3 mg, which is equivalent to 330 mg of L-carnitine base. Also, tablets enable the use of many excipients in quantities sufficient to overcome the adverse effects of L-carnitine-L-tartrate hygroscopicity on tablet properties.Many problems are expected during the formulat...

Objective: The aim of this work focused on formulation and evaluation of sildenafil 50 mg orodispersible tablets by sublimation technique. Methods: Active ingredient and excipients mixtures were evaluated for physicochemical changes of the drug utilizing FTIR spectroscopy and DSC thermal analysis. Nineteen proposed formulae N1-N19 were prepared by sublimation technique using menthol as a sublimating agent. Three different types of superdisintegrants (sodium starch glycolate, croscarmellose sodium and plasidone XL) were used in three different ratios (3, 6 and 9 % w/w), percentage of inter-granular and intragranular disintegrant. Hydrophilic filler such as mannitol and hydrophobic filler such as microcrystalline cellulose were used in the ratio (1:1, 2:1 and 4:1 w/w).Elimination of bitterness using sucralose as a potent sweetener. Granulation was achieved by alcoholic solution of PVP K25 as binder at Diosna® high shear mixer. Lubricant (hydrophobic magnesium stearate and hydrophilic sodium stearyl fumarate). Un-lubricated granules were characterized for bulk density, tapped density, true density, particle size distribution, Carr'sindex, Hausner ratio, flow rate and angle of repose. Tablets were firstly compressed on rotary machine then subjected to vacuum oven at 60 ᵒ C for 6 hours. Post compression characterization for tablets after sublimation including content uniformity, average weight, hardness, thickness, In-vitro disintegration, friability, wetting time, assay and dissolution profile of the proposed formulae against the immediate release marketed tablet Viagra ® 50 mg tablet. Results: The formula (N 16) which granulated using 1% PVP k25 with 9% plasidone XL (60% of it is inter-granular while 30% intra-granular), menthol 1%, Microcrystalline cellulose: Mannitol 1:1 and magnesium stearate was the most effective formulation as it showed wetting time of 30.7 seconds, disintegration time of 25 seconds and cumulative % drug release of 92.8 and 95.8 % after 1 and 3 minute respectively. Conclusion: Sildenafil 50 mg ODT successfully was prepared by sublimation technique with better wetting time, disintegration time, assay dissolution profile, hardness and friability.

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