Some chemical characteristics of novel hemicellulosic Gums From seeds of Afzelia africana and Prosopis africana

Background: Determination of chemical characteristics of a pharmaceutical excipient is important for establishing its compatibility with different drugs.

Objective: This study investigates some chemical characteristics of novel hemicellulosic gums extracted from seeds of Afzelia africana and Prosopis africana.

Methods: The afzelia gum (AFG), prosopis gum (PRG) and sodium carboxylmethylcellulose (SCMC) were subjected to ash value evaluation, pH determination, atomic absorption spectroscopy, fourier transform infrared analysis and X-ray powder diffraction.

Results: Afzelia seeds gave a yield of 17 % gum while prosopis seeds gave a yield of 18.2 %. There was no significant difference in the yield of hemicelluloses from the two seeds. AFG gave a significantly higher ash value compared to PRG signifying the presence of higher amount of inorganic substances. There was no significant difference in the pH of their dispersions. The two hemicelluloses contain significantly higher amount of potassium and magnesium ions compared to SCMC. The three polymers manifested similar X-ray diffraction patterns showing that they are closely related.

Conclusion: The two hemicellulosic gums can be differentiated from synthetic cellulose derivatives like SCMC on the basis of their potassium and magnesium content. However, being cellulose-related, they are all characterized by similar X-ray diffraction patterns. The type and level of the different metal ions present in the gums reflect their compatibility or otherwise with different types of drugs.