where,
Ea: | Activation energy |
R: | Gas constant |
T1: | Temperature of the experiment of known rate constant, K1 |
T2: | Room temperature at which the rate constant, K2 is to be determined |
K1: | Known rate constant at T1 |
K2: | Rate constant at the room temperature |
Estimation of Shelf Life of Powdered Leaves, Ethanolic and Aqueous Extracts, Alcoholic and Aqueous Liquid Formulations at Room Temperature
The shelf life of powdered leaves, ethanolic and aqueous extracts, alcoholic and aqueous liquid formulations of L. micranthus at room temperature was determined by substituting into the first order equation shown below:
where,
| t0.9: | Time at which 90 per cent of the initial concentration of the drug remains. |
| K: | Degradation rate constant of the formulation at room temperature |
| A: | initial concentration of the formulation |
| X: | 90 per cent of the initial concentration of the formulation |
Results and Discussion
The results of pH and the organoleptic properties of the ethanolic and aqueous formulations are shown in Table 22.1. Both formulations are palatable, a condition that will favour acceptance and hence compliance by patients. The aqueous extract formulation was more acidic than the ethanolic extract formulation. The absorption of the formulations into the body will vary from one region of gastrointestinal tract to the other. The drug is most likely to be absorbed in the stomach (pH, 1-3), since in this region the drug will be largely unionized.
In the stability studies of the powdered leaves, extracts and liquid formulations of L. micranthus, we employed the developed and validated spectrophotometic assay for flavonoids present in the plant products. This approach was adopted because the material under investigation is a herbal drug and constituent of known therapeutic activity is not known (EMEA, 2001).
Table 1: Result of determination of pH and organoleptic properties of formulations
Formulation | Batch | Colour | Taste | pH |
