Solubility improvement of gallic acid in water through cocrystal formation with the solvent-drop grinding method and tartaric acid as co-former

Abstract

Background: Quality, safety, and efficacy are required in pharmaceutical preparations on the market. The role of tested active substances and additives in producing a product formula that is stable, consistent, and meets standards. Solubility is an important parameter for achieving systemic drug concentration and pharmacological response. Cocrystals, for example, have been studied extensively to increase their solubility. Solvent-drop grinding is used to combine active pharmaceutical substances with co-formers into a single crystal unit. Gallic acid is an antioxidant, antimicrobial, anti-inflammatory, anticancer, cardioprotective, gastroprotective, and neuroprotective chemical compound. It is soluble in water thus used to make cocrystals. Also, tartaric acid is crystallised, inert, and easily soluble in water, so it is a natural choice as a co-former. Objectives: Solvent-drop grinding was used to characterise the gallic acid cocrystal formation with tartaric acid co-former, and the effect of gallic acid cocrystal formation with tartaric acid as a co-former was tested using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Method: The ratios of gallic acid cocrystals to tartaric acid co-formers were 1:0, 1:1, and 2:1. After crushing gallic and tartaric acids for four minutes, a few drops of ethanol solvent were added until the mixture was homogeneous. Result: There was an increase in the cocrystal solubility test. The presence of hydrogen bonds between the co-formers of gallic and tartaric acids is indicated by a wavenumber shift in the cocrystal's infrared spectrum. Furthermore, each cocrystal creates a new peak in the X-ray pattern, indicating that hydrogen bonds formed cocrystals. Conclusion: The co-crystallisation method can increase the solubility of gallic acid in water by 1.21 times.