Synthesis and Characterization of Compounds Related to Lisinopril.

Lisinopril is a drug of the angiotensin-converting enzyme (ACE) inhibitor class that is primarily used in the treatment of hypertension. During the scale-up of the lisinopril process, one unknown impurity was observed and is identified. The present work describes the origin, synthesis, characterization, and control of this impurity.

Identification, isolation and characterization of impurities of clindamycin palmitate hydrochloride.

Clindamycin palmitate hydrochloride is a water soluble hydrochloride salt of the ester of clindamycin and palmitic acid. It is inactive in vitro, rapid in vivo hydrolysis converts this compound to the antibacterially active clindamycin. Total 12 impurities at levels ranging from 0.

Impurity profile study of lopinavir and validation of HPLC method for the determination of related substances in lopinavir drug substance.

Several related substances (RS4-RS10) were detected in lopinavir drug substance at levels ranging from 0.03% to 0.1% by employing gradient RP-HPLC.

Identification, isolation and characterization of potential degradation product in risperidone tablets.

One unknown impurity (degradation product) present at a level below 0.1% in the initial samples increased to a level of 0.5% in 6M/40 degrees C/75% RH stability samples of risperidone tablets was detected by gradient reverse-phase high-performance liquid chromatography (HPLC).

Identification and characterization of new impurity in didanosine.

Didanosine is an antiviral drug. During the preparation of didanosine in our lab, six process related known impurities and one unknown impurity were detected in HPLC analysis at levels ranging from 0.05 to 0.

Impurity profile study of zaleplon.

Zaleplon is a pyrazolopyrimidine derivative and possesses sedative and hypnotic properties. Seven unknown impurities in zaleplon bulk drug at levels below 0.1% were detected by reverse-phase high performance liquid chromatography (HPLC).

Isolation, structural elucidation and characterization of impurities in Cefdinir.

Three unknown impurities in Cefdinir bulk drug at levels below 0.2% (ranging from 0.05 to 0.

Structural identification and characterization of impurities in ceftizoxime sodium.

Ceftizoxime sodium is a parenteral beta-lactamic antibacterial drug. In the synthesis of ceftizoxime sodium, eight process related impurities were detected in HPLC analysis. Pure impurities obtained by both synthesis and preparative HPLC were co-injected with ceftizoxime sample to confirm the retention times in HPLC.