Investigation of the Concentration Goodness for some Liquid Drugs Using Light Angular Scattering

In this work a simple setup was built to measure the angular scattering of laser light as an approach for testing the quality of some pharmaceutical solutions (conc.) and detect any change in that concentration with respect to the standard one suitable for desired dose. A laser diode with wavelength 671 nm and output power 100 mW and a photomultiplier tube were used to find the relation between drug concentration and the scattered intensities of the laser beam at angles 45°, 90° and 135° with respect to the direction of incidence for the samples: Benzylpenicillin sodium (BS), metronidazole and actrapid HM (insulin human) (IH). The results showed that the relation between the angular scattered intensity and sample concentration is linear. The study proved that this setup is very sensitive to detect the scattered laser intensity for any change in sample concentration from its standard concentration. It was found that even for very small change in the concentration of BS sample, as example by (0.04 g/ml) the setup gave clear reading of this change. Also, a change in the concentration of (IH) sample just by (0.025 g/ml) gave clear differences in the scattered intensity at all angles. From the features mentioned above it is clear that this setup is very efficient in discovering any manipulation in the drug concentration.