A good number of formulations used in Ayurveda are oral liquid doses forms. Various analytical parameters used in pharmacopoeia are to ascertain minimum quality and accuracy of medication delivery with specified dosing devices. Viscosity is one among those parameters measuring resistance to flow based on molecular adhesion and cohesion within the fluid. The Maintenance of viscosity in pharma products relies upon the best available delivery system with aim to optimized release of medicinal compounds at the site. Increased viscosity in cough syrup provides soothing, demulcent and humectant effects. Modified higher viscosity has compound release problems, so a modified version should be opted only after researches.
Oils and Ghritas are another important oral lipid-based formulations of various medicinal compounds. They are good vehicles for poorly water-soluble drugs. They accelerate dissolution processes and enhances solubilised phases by reduced particle size. Lipid-based formulations also increase the membrane fluidity and stimulates lipoprotein production. These all together facilitate absorption. The viscosity of such formulations depends upon the bases used as sesame oil, ghrita etc. Enhanced viscosity compared to aqueous formulations is associated with delayed gastric emptying and sustained release of compounds at the site.
The size of fatty acid chains is directly correspondent to viscosity. Even, the digestive pattern varies according to the size of fatty acids. Oil contains long chain fatty acids and medium chain fatty acids while ghritas contain short chain fatty acids and medium chain fatty acids. The long chain fatty acids need cholecystokinin, pancreatic enzymes and carnitine acyltransferase. They are reaching to systemic circulation via intestinal lymphatic system. The short chain and medium chain fatty acids are not dependent on carnitine acyltransferase for transport to mitochondria. They are absorbed via passive diffusion along the gastrointestinal tract in to portal system bound to albumin.
So, researches are required for every viscous ayurvedic formulation to measure appropriate viscosity. This must be based on ingredients added following standard operating procedures as temperature treatment and base added are essential factors for change in viscosity.