title: Validated enantiospecific LC method for determination of (R)-enantiomer impurity in (S)-efavirenz.
abstract: A high-performance liquid chromatographic method was developed for separation of the enantiomers of efavirenz. The developed method was applied for the determination of (R)-enantiomer in (S)-efavirenz and satisfactory results were achieved. The base line separation with a resolution of more than 4.0 was achieved on Chiralcel OD (250 mm x 4.6 mm, 10 microm) column containing tris-(3,5-dimethylphenylcarbomate) as stationary phase. The mobile phase consists of n-hexane: isopropyl alcohol (80:20 v/v) with 0.1% (v/v) of formic acid as additive. The flow rate was kept at 1.0 ml/min and the UV detection was monitored at 254 nm. The (R)-enantiomer was found linear over the range of 0.1 microg/ml--6 microg/ml. The limit of detection (LOD) was 0.03 microg/ml and the limit of quantification (LOQ) was 0.1 microg/ml (n=3. The precision of (R)-enantiomer at LOQ level was evaluated through six replicate injections and the RSD of the peak response was achieved as 1.34%. The results demonstrated that the developed LC method was simple, precise, robust and applicable for the purity determination of efavirenz.
authors.affiliation: Quality Assurance, Matrix Laboratories Limited, Secunderabad, India. chalam_us@rediffmail.com
authors.forename: U
authors.initials: U
authors.lastname: Seshachalam
authors.forename: D V L
authors.initials: DV
authors.lastname: Narasimha Rao
authors.forename: K B
authors.initials: KB
authors.lastname: Chandrasekhar
mesh_terms: D000480:Alkynes; D019380:Anti-HIV Agents / Q000737:chemistry* / Q000302:isolation & purification; D048588:Benzoxazines / Q000737:chemistry* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D003521:Cyclopropanes; D010316:Particle Size; D012015:Reference Standards; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; C098320:efavirenz