Simultaneous determination of prostaglandins (PG) E2, A2 and B2 and stability studies of PGE2 in pharmaceutical preparations by ion-pair reversed phase HPLC.

In previous reports a direct thin-layer chromatographic method (TLC) for the determination of prostaglandins (PG) E2, A2, B2 and F2 alpha and a High-Performance Liquid Chromatographic method (HPLC) for the determination of PGE2-, PGA2- and PGB2- descendants and for stability studies of PGE2-descendant in pharmaceutical preparations were described In this paper the described HPLC method and a newly developed technique based on ion-pair HPLC are given for the simultaneous determination of PGE2, PGA2 and PGB2 and for the stability studies of PGE2 in pharmaceutical preparations. The extraction of PG's from pharmaceutical preparations is performed in a fully automated, electronically controlled extraction apparatus within 3 minutes. Ion-pair reversed phase HPLC is performed on a column of LiChrosorb RP18 using either methanol-water-octan-1-sulfonic acid sodium salt (55 ml + 45 ml + 65 mg) or methanol-water-tetrabutylammoniumperchlorate (360 ml + 290 ml + 1.0 g) as eluent. HPLC separation can also be performed on a column of mu-Bondapack C18 using methanol-n-butanol-glacial acetic acid-water (350 ml + 45 ml + 5 ml + 400 ml) as solvent. The stability of PGE2 is investigated in pure substance, in ethanolic-aqueous solution, in absolute ethanolic solution and in freeze-dried ampoules. The examined preparations are stored at temperatures between 4 and 40 degrees C and are investigated periodically. The stability studies of PGE2 indicate that PGA2 and PGB2 are formed as degradation products of PGE2. The prediction of the stability studies of PGE2 indicate that this active drug is unstable in pure substance as well as in pharmaceutical preparations.(ABSTRACT TRUNCATED AT 250 WORDS)