Physicochemical properties and lubricant potentials of Blighia sapida   Sapindaceaeae seed oil in solid dosage formulations

Purpose: To investigate and compare the physicochemical properties and lubricant potentials of Blighia sapida seed oil (BSSO) with those of magnesium stearate, a commercial lubricant.
Methods: The dried seeds of Blighia sapida (BS) powder were macerated with n-hexane for five days to separate the oil. The physicochemical properties; solubility profile, acid value, saponification value, iodine value of the oil were determined using standard methods. Batches of ascorbic acid tablets compressed at same compression settings using different concentrations of BSSO as lubricant were evaluated for their friability, weight uniformity, tablet hardness, disintegration and dissolution.
Results: BSSO had a density of 0.9 g/ml, acid value of 2.65 ± 0.20 mg KOH/g, saponification value of 141.65 ± 0.75 mg KOH/g, iodine value of 62.50 ±3.71 mg I₂/g among other parameters. Fatty acid methyl ester analysis (FAME) revealed 96.89 % of monounsaturated fatty acids and esters in the range of C₁₅-C₂₃; a C₂₃ compound, 22-tricosenoic acid was the dominant compound (46.82 %). The oil showed excellent lubrication properties in ascorbic acid tablets at a low concentration (0.5 %), similar to 2 % magnesium stearate. However, higher concentration (5 %) of BSSO resulted in granules that could not be compressed into tablets. Tablets containing BSSO demonstrated satisfactory friability, weight uniformity, hardness, disintegration and dissolution characteristics.
Conclusion: Blighia sapida seed oil is a potentially useful low-cost tablet lubricant. However, further investigations on the excipient, including stability, toxicity, etc, are required to ascertain its suitability.

Keywords
Blighia sapida; Lubricants; Seed oil; Excipients; Ascorbic acid; Tablet properties; 22-Tricosenoic acid