In recent years, glutathione has shown important uses in cosmetology and in the treatment of many diseases. However, it was noted that there are many problems confronting us in the commercially available pharmaceutical forms. The most important of them are its absorption, bioavailability, duration of action, and side effects, which limit its use. The present study was carried out to prepare a subcutaneous injectable sustained release microparticles dosage form loaded with L-Glutathione by using PLGA polymer, to improve bioavailability, prolong its residence in the body, and reduce the side effects caused by other pharmaceutical forms, which will overall result in its becoming more widely accepted and marketable. Four different batches of polymer microspheres (10, 20, 40, 60 mg) were prepared in a 20 g batch and stored at 2-8°C and protected from light, according to USA patent 7612176. The finished product microspheres were characterized for drug content, molecular weight of the polymer, particle size of the particle, moisture content, residual solvents (DCM, cyclomethicone, and SiO), FT-IR, and DSC. In addition, in vitro release was also performed using the HPLC method and delivered drug over 5 days. Results obtained using the HPLC method showed that the loadings were 72%, 82%, 79%, and 91% for batches 1, 2, 3, and 4, respectively. While the molecular weight was approximately the same for each batch at 60 KDa. Through the moisture content measurement, the result showed that batch 3 presented the lowest amount with 0.45%, compared with batches 2, 3, and 4, so that the results consecutively were 0.88, 0.87, and 0.99%. However, it could be possible to formulate successfully sustained release microspheres of L-Glutathione using PLGA as a polymer. The developed microspheres are a good candidate for further in vivo evaluation.