Release study of sulphamethoxazole controlled by swelling of gelatin nanoparticles and drug-biopolymer interaction

Gelatin (Type A) particles were prepared by a single W/O emulsion technique and characterized by infrared (IR) spectra, scanning electron microscopy (SEM) and particle size analysis. Whereas the IR spectra clearly confirmed the presence of gelatin and sulphamethoxazole (SM) in the loaded nanoparticles, the scanning electron micrograph (SEM) image depicts smooth surface, spherical shape and uneven size of nanoparticles (100 to 300 nm). The nanoparticles were evaluated for their potential to act as a carrier of sulphamethoxazole drug. It was found that the amount of released SM increases with increasing percent loading of the drug in the range 18 to 39%. The chemical architecture of nanoparticles was also found to influence its drug-releasing capacity. It was observed that in the case of an increase in gelatin and crosslinker (gluteraldehyde) concentrations in the range 4.0-9.0 g and 5.3-31.8 mM, respectively, the amount of released SM initially increases up to 8.0 g of gelatin and 10.6 mM of crosslinker concentrations and thereafter decreases. It was also noticed that a greater release of SM occurs when type B gelatin is used as drug carrier. The influence of experimental conditions such as pH and temperature of the release medium were also investigated on the release profiles of SM. It was noticed that an optimum release is obtained at pH 7.4, while in the case of a variation of temperature in the range 10 to 35 degrees C, a maximum release is found at 25 degrees C. Beyond 25 degrees C, a fall in the released SM was observed. The drug was also found to be chemically stable at pH 1.8 (gastric juice) as confirmed by UV spectral study.