Accelerated Stability Studies of Three Local Drug Products Prone to Hydrolysis

Abstract

Three locally manufactured drug products, Aspirin 300 mg tablets, Chloramphenicol 250 mg capsules and Ampicillin Trihydrate 500 mg capsules, obtained from three production batches, were exposed to storageconditions maintained at 40 °C and 75% relative humidity (RH) in a stability chamber. The products were packed in hospital packs either in high-density polyethylene (HDPE) plastics (chloramphenicol and ampicillin trihydrate capsules) or in metal tins (aspirin tablets) as well as in unit dose blister-packs made up of /PVC/PVDC/aluminum. As a negative control, some samples were left open /unpacked/ in the stability chamber. Physical and chemical stabilities were investigated at zero-, three- and six-month intervals. During the six-month storage, hospital-packed and the negative control (left open) aspirin tablets showed some
physical changes including the production of a strong odour of acetic acid and tendencies to stick together. The negative control tablets showed a significant change in their moisture content. Furthermore, blister packed tablets showed a decrease in mechanical strength. Aspirin tablets stored for six months under all storage conditions failed to release 50% of the drug within 30 min. HPLC assay results showed decrease in drug content in all the three duration of storage. Chloramphenicol capsules showed significant gain of moisture under all durations of storage. After storage for six months, these capsules also failed to release 80% of the drug within 30 min. The HPLC assay results indicated drastic decline in drug content of the negative control (left open) capsules. Ampicillin trihydrate showed change in colour from white to yellowish under all durations of storage. After storage for six months, except for the negative control (71.3%) capsules, blister (92.25%) and HDPE (84.64%) packed capsules released more than 75% of the drug within 45 min. The spectrophotometric assay results showed, there was a significant decrease in the drug content of the negative control capsules (from 99.16% at zero-time to 68.88%) at six-month time. Blistered and HDPE packed capsules also exhibited decline in ampicillin trihydrate content, 92.34 and 88.28%, respectively, after the end of the storage time.

Keywords: aspirin, chloramphenicol, ampicillin trihydrate, stability studies, HPLC analysis

Ethiopian Pharmaceutical Journal Vol. 24 (2) 2006: pp. 106-115