Chiral analysis of drug substance in clinical plasma extracts using achiral HPLC with circular dichroism detection

A circular dichroism (CD) detector in series with a UV detector was used with reversed-phase gradient HPLC to do the chiral analysis of unresolved enantiomers of a single stereoisomer drug substance in extracts of clinical plasma samples. The CD/UV peak area ratio of the unresolved enantiomers in the plasma extracts was calculated and compared with pure drug substance standards to show that there was no racemization of the chiral center during pharmacokinetic studies. The CD detector can be used only with chiral compounds with a UV chromophore and the limit of detection was approximately 5 ng with the drug substance and chromatographic conditions used in this study.

Dihydrochalcones from Piper longicaudatum

Bioactivity-guided fractionation of an ethanolic extract of the leaves and twigs of Piper longicaudatum Trelease & Yunker (Piperaceae) resulted in the isolation of one new (1) and three known (2-4) dihydrochalcones. The known compounds are: 2',6'-dihydroxy-4'-methoxydihydrochalcone (2), 2',6',4-trihydroxy-4'-methoxydihydrochalcone (asebogenin) (3), and 2'-hydroxy-4'-methoxy-2'-[1-hydroxy-1-methylethyl]-2",3"-dihy- drofurano[4",5":5',6"]-3"-[2-hydroxy-5-methoxycarbonylphe- nyl]dihydrochalcone (piperaduncin B) (4). The new compound is 2'-hydroxy-4'-methoxy-2"-[2-hydroxy-5-methoxycarbonyl- phenyl]-furano[4",5":5',6']-dihydrochalcone (longicaudatin) (1). Compounds 1-4 were tested for antibacterial activity against S. aureus and methicillin-resistant S. aureus (MRSA); only compound 3 showed inhibitory activity (IC50 of 10 and 4.5 micrograms/ml, respectively).

Elimination pathways of [14C]losoxantrone in four cancer patients

Losoxantrone is an anthrapyrazole derivative in Phase III development in the U.S. for solid tumors, notably breast cancer. To obtain information on the routes of elimination of the drug, a study was conducted in four patients with advanced solid tumors, which involved intravenous administration of 100 microCi of [14C]losoxantrone for a total dose of 50 mg/m(2) during the first course of losoxantrone therapy. Blood, urine, and feces were collected for up to 2 weeks and were analyzed for total radioactivity and parent drug. In addition, feces were profiled for the presence of metabolites. Plasma concentrations of total radioactivity exhibited a temporal pattern similar to the parent drug. Combined recovery of administered total radioactivity from urine and feces was 70% with the majority (87%) of this radioactivity excreted in the feces, presumably via biliary excretion. Feces extracts were profiled for metabolites using a high-performance liquid chromatography method developed to separate synthetic standards of previously identified human urinary metabolites. Only intact losoxantrone was found in the feces. About 9% of the dose was excreted in the urine, primarily during the first 24 h and mostly in the form of parent compound. Collectively, these data indicate that fecal excretion of unmetabolized drug via biliary and/or intestinal excretion is the primary pathway of intravenously administered losoxantrone elimination in cancer patients with refractory solid tumors.

Antifungal chalcones from Maclura tinctoria

Five prenylated flavonoids, including one new natural product, were isolated from an ethanol extract of the leaves of Maclura tinctoria (L.) Gaud. The new compound has been characterized as 2',4',4,2''-tetrahydroxy-3'-[3''-methylbut-3''-enyl]chalcone (1). The known compounds were identified as 2',4',4-trihydroxy-3'-[3''-methylbut-3''-enyl]chalcone (isobavachalcone) (2), 4,2'-dihydroxy-2''-[1-hydroxy-1-methylethyl]-2'',3''-dihydrofurano[4'',5'':3',4']chalcone (bakuchalcone) (3), 4,4',5''-trihydroxy-6'',6''-dimethyldihydropyrano[2'',3'':5',6'']chalcone (bavachromanol) (4), and 5,7,3',4'-tetrahydroxy-6,8-diprenylisoflavone (6,8-diprenylorobol) (5). All the isolated compounds were evaluated against the AIDS-related opportunistic fungal pathogens, Candida albicans and Cryptococcus neoformans. Compound 2 was active against both yeasts.

Acquisition of Helicobacter pylori infection and reinfection after its eradication are uncommon in Indian adults

BACKGROUND

Eradication of Helicobacter pylori infection is known to decrease the recurrence rate of peptic ulcer disease. Data from India on the acquisition rate of H. pylori infection and reinfection after eradication are scant.

AIM

To study the rates of acquisition of H. pylori infection and of reinfection after eradication in Indian adult patients.

METHODS

We evaluated 116 consecutive patients with dyspepsia undergoing endoscopy. Sixty-four of them were H. pylori-positive on gastric antral biopsy (rapid urease test and histology). Patients diagnosed to have H. pylori infection were treated with a four-drug regimen (omeprazole, bismuth subcitrate, tetracycline, furazolidine) for 2 weeks; those failing H. pylori eradication were treated with a second regimen (lansoprazole, amoxycillin, secnidazole) for one week. Patients who were H. pylori-negative to begin with and those who had successful H. pylori eradication were followed up clinically and endoscopically every 3 months for a median of one year.

RESULTS

Ninety-six patients (50 H. pylori-positive) were available for study; the other 20 were lost to follow up after the first endoscopy. Fifty of the 96 (52%) were H. pylori-positive; four of these 50 patients did not follow up after first treatment. The eradication rate with the four-drug regimen was 89.1% (41/46). Four of the 5 non-responders eradicated H. pylori with the second regimen. At the end of median one year follow-up (range 9-15 months), one of the 45 patients (2.4%) who eradicated the organism developed reinfection; none of the 46 patients who were initially H. pylori-negative acquired new infection.

CONCLUSIONS

The risk of reinfection after eradication is low in Indian subjects at the end of one year. The rate of acquisition of new infection is also low in the adult population.

Hepatic sickling crisis mimicking recurrent cholangitis

A 22-year-old man with homozygous sickle cell disease presented with recurrent fever, right upper quadrant pain and jaundice. Liver biopsy confirmed the diagnosis of hepatic sickling crisis; the symptoms responded to hydroxyurea therapy. Hepatic vasocclusive crisis can diagnosed on liver biopsy, and need not be a diagnosis of exclusion.

Phase I safety and pharmacokinetic studies of brequinar sodium after single ascending oral doses in stable renal, hepatic, and cardiac allograft recipients

Brequinar sodium (BQR), a substituted 4-quinoline carboxylic acid, was in clinical development in combination with cyclosporine (CsA) as a potentially effective therapy for the treatment and prophylaxis of rejection in organ transplant patients. This phase I study was performed in stable renal, hepatic, and cardiac transplant patients receiving CsA and prednisone maintenance therapy for immunosuppression. The pharmacokinetic objectives of this study were to characterize the pharmacokinetics of (a) single oral 0.5- to 4-mg/kg doses of BQR when given in combination with CsA and prednisone to stable renal, hepatic, and cardiac transplant patients and (b) steady-state oral doses of CsA, with and without single oral doses of BQR. In all three patient populations, the pharmacokinetics of BQR were characterized by a lower oral clearance (12-19 mL/min) than that seen in previous studies in patients with cancer (approximately 30 mL/min at similar doses) and a long terminal half life (13-18 hrs). This slower oral clearance for BQR could be due either to a drug interaction between BQR and CsA or to altered clearance or metabolic processes in patients with transplants. Steady-state CsA trough levels and the oral clearance of CsA were not affected by BQR coadministration. Among the three transplant populations, the cardiac transplant patients had lower oral clearance values of BQR and of CsA. The cause of this lower clearance is not known. Safety results indicate that BQR was well tolerated by this patient population.

Mesenteric vasculopathy in intestinal tuberculosis

BACKGROUND

Involvement of mesenteric vessels in intestinal tuberculosis and its role in the pathogenesis of the intestinal changes have not been studied histologically.

AIM

To study mesenteric vessels in patients undergoing surgery for complications of intestinal tuberculosis.

METHODS

Resected intestinal specimens from 68 patients presenting with intestinal perforation and intestinal obstruction were examined; involvement of the major mesenteric vessels was evaluated.

RESULTS

Granulomas were seen in the vessel wall in one case and near the vessel wall in 11 cases, intraluminal thrombi were seen in 23 cases, and subintimal fibrosis in nine cases. Perivascular cuffing was seen in intramural and subserosal vessels in ten cases.

CONCLUSIONS

Changes in the vessel wall may lead to gut ischemia, which may contribute to the development of strictures and stercoral perforation in intestinal tuberculosis.

Effect of drying conditions on the taxane content of the needles of ornamental Taxus

The effect of drying intact clippings of Taxus on the recovery of taxol and related compounds was studied under different drying conditions which included tobacco drying barn, greenhouse, shadehouse, air conditioned laboratory, oven, and freeze-drying. For clippings dried under tobacco barn, greenhouse, oven, and freeze-drying conditions, nearly total recovery of the expected levels based upon projections from analysis of fresh biomass was observed for taxol and cephalomannine. However, only 75-80% of the expected values for 10-deacetyltaxol and 10-deacetylbaccatin III were found. When the length of drying was extended up to 10 and 15 days as in the shadehouse and laboratory conditions, the recovery of all taxanes was adversely affected.

Bleeding ileal schwannoma

We report a case of ileal schwannoma who presented with bleeding per rectum. Three-vessel angiogram was the only diagnostic investigation, and revealed tumor blush in the mid-ileal region. On exploration, an intraluminal mass was found in the mid-ileal region along with a feeding vessel in the mesentery. Resection of the involved ileum with end-to-end anastomosis was done. Histopathology showed benign schwannoma of ileum involving the submucosa, muscularis propria and serosa.

Variability in the pharmacokinetics and pharmacodynamics of low dose aspirin in healthy male volunteers

Data describing the pharmacokinetics and pharmacodynamics of low dose aspirin (acetylsalicylic acid; ASA) are limited. This single-center study was designed to determine the rate and extent of oral absorption of 80-mg ASA tablets in healthy, young male subjects and to assess the intra- and inter-subject variability of ASA pharmacokinetics and platelet aggregation effects. Ten subjects each received a single, open-label, oral 80-mg ASA dose on three separate days. Each dose was separated by a 2-week washout interval. Blood samples for pharmacokinetic determinations of ASA and its metabolite, salicylic acid (SA) and platelet aggregation studies were obtained at scheduled timepoints before and up to 24 hours after each dose. Peak plasma ASA levels of 1 microgram/mL were achieved within 30 minutes. Peak plasma SA levels of approximately 4 micrograms/mL were attained in 1 hour. The terminal half-lives (t1/2) of ASA and SA were 0.4 and 2.1 hours, respectively. Both ASA and SA pharmacokinetics and the platelet aggregation response to ASA exhibited considerable intra- and inter-subject variability. Inhibition of platelet aggregation was found to relate with ASA area under the plasma concentration versus time curve (AUC).

Adult Hirschsprung's disease

Hirschsprung's disease in adulthood is a rare entity. We report Hirschsprung's disease in a 35-year-old woman who had absence of anorectal inhibitory reflex on manometric studies.

Non-specific granulomatous inflammatory lesions of small bowel

The entity of nonspecific granulomatous inflammatory lesions(NSGIL) of the small bowel is a diagnostic and therapeutic dilemma. Data of 52 histopathologically proven cases of NSGIL seen by us between 1986 and 1991 were analysed. All these patients presented with either intestinal obstruction or perforation. They were thoroughly evaluated and investigated for tuberculosis. Of the 52 patients, 6 patients received antitubercular therapy (ATT) before and after surgery and 32 patients only after surgery. Fourteen patients did not receive ATT. Surgical procedures undertaken included stricturoplasty, resection/anastomosis and simple suturing of perforation. No complications were seen in patients who received ATT; however, six of 14 patients who did not receive ATT developed wound sepsis and 2 developed partial wound dehiscence. Many of these NSGIL lesions could be tuberculous in etiology though typical caseating granulomas were not seen.

Simultaneous quantification of an anti-inflammatory compound (DuP 697) and a potential metabolite (X6882) in human plasma and urine by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method using fluorescence detection has been developed for the simultaneous analysis of low nanogram concentrations of an anti-inflammatory drug, 5-Bromo-2-(4-fluorophenyl)-3-[4-(methylsulfonyl)phenyl]thiophene (DuP 697), and a potential metabolite (X6882) in human plasma and of DuP 697 in human urine. This assay method used an EM Separations Lichrospher C18 endcapped column. The mobile phase was acetonitrile-water (75:25, v/v). The detection of DuP 697 and X6882 was by fluorescence at excitation and emission wavelengths of 256 and 419 nm, respectively. The chromatographic system could separate DuP 697 from X6882, the external standard (anthracene), and other endogenous substances present in human plasma. In human plasma the limits of quantification for DuP 697 and X6882 were 3 and 20 ng/ml, respectively; the limit of quantification for DuP 697 in human urine was 5 ng/ml. These compounds were shown to be stable in frozen (-20 degrees C) human plasma and urine for at least 9 weeks. The assay described has been used to characterize DuP 697 pharmacokinetics after oral administration in humans.

Fibrolamellar hepatocellular carcinoma

Fibrolamellar hepatocellular carcinoma, a histological variant of hepatocellular carcinoma, distinct pathological and clinical features and a better prognosis than other types of hepatocellular carcinoma. We report here a patient who was treated on successful surgically.

Congestive jejunopathy in portal hypertension

Twenty six patients with portal hypertension of different aetiologies were studied for endoscopic evidence of congestive gastroduodenopathy and histological evidence of congestive gastropathy and jejunopathy. Per oral biopsies of jejunum were taken by Watson's capsule. Normal biopsy tissues obtained from the antrum (26), fundus (10), and jejunum (26) were used as controls. Endoscopy showed congestive changes in the fundus (17 cases), antrum (17), and duodenum (4). Duodenopathy correlated with changes in the antrum but not in the fundus. Histology showed an increase in the size and number of vessels in the jejunal villi ('congestive jejunopathy') in 22 patients. These correlated with histological evidence of gastropathy in the fundus but not in the antrum. The incidence of congestive jejunopathy did not correlate with the Child-Pugh score in patients with cirrhosis or with the number of sclerotherapy sessions received. Congestive jejunopathy is part of the spectrum of congestive gastroenteropathy and occurs at least as frequently as changes in the stomach and duodenum. The clinical import of these jejunal changes remains to be explained.