Formulation and evaluation of acetaminophen suspension using fenugreek seeds as a natural suspending agent

Abstract

A great number of pharmaceutical excipients, both natural and synthetic, are available to meet the demands of the rapid development of the pharmaceutical industry. Nowadays, naturally derived excipients are preferred over synthetic excipients owing to their greater availability in nature, biocompatibility, biodegradability, non-toxicity, environment friendliness and cost-effectiveness. A good example of a natural source of excipient is Trigonella foenum graceum (Family: Leguminosae) seeds, also known as fenugreek seeds, which contains a high percentage of mucilage and forms viscous tacky mass that swells up when exposed to fluids and thus can be used as a suspending agent in pharmaceutical suspensions. The aim of the present study was to utilize fenugreek mucilage as a natural suspending agent by formulating and evaluating a suspension containing acetaminophen as the active pharmaceutical ingredient and incorporating fenugreek mucilage as the suspending agent. Five formulations (FS1 – FS5) each containing varying proportions of Trigonella foenum graceum mucilage, were prepared. The suspensions were subjected to evaluation by studying different parameters like pH, sedimentation volume, degree of flocculation, viscosity, redispersibility, flow rate, effect of temperature on viscosity and finally the rate of release of drug within twenty minutes. pH of all the formulations were found to be similar (approximately 7.8). The sedimentation volume did not change significantly over a period of 45 days indicating higher degree of flocculation and good stability of the suspensions. The suspensions were easily redispersible after shaking only twice even after 45 days and the flow rate of the suspensions did not differ much suggesting that suspensions with 2 gm of mucilage (FS4) can be used instead of FS3 (with 1.5 gm of mucilage) as it gives a higher degree of flocculation. The dissolution results of the suspensions were found to be satisfactory since on an average 65-70% of the drug was released within 20 minutes, thus complying with USP specifications. Even though all the formulations gave good results, it can be concluded that FS4 formulation is the optimum formulation with greater flocculation, good flow rate and easily redispersibility characteristics along with a good percentage release of drug within twenty minutes. These formulations can be compared with the market preparations for further evaluation.