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Biomedical subjects

J C Cradock

Publications and source records attributed to J C Cradock.

33 records · Page 2Linked to original sources
PubMed1979

Simple high-performance liquid chromatographic method for the separation of 3,6-diacetylmorphine hydrochloride (heroin) and hydrolysis products.

The application of reversed-phase high-performance liquid chromatography to the measurement of 3,6-diacetylmorphine (DAM) hydrochloride and its degradation products is described. This method has been applied to study the kinetics of the DAM hydrolysis at 26 +/- 0.1 degrees and 48 +/- 0.1 degrees. The hydrolysis of DAM involved a two-step first-order sequential mechanism between pH 3 and 8.6. The first-order rate constants of each step at all pH levels have been determined. The pH rate profile was constructed from kinetic measurements and demonstrated that stability of DAM hydrochloride solutions was optimal at pH 4.3. This information is being applied to the development of parenteral dosage forms of DAM hydrochloride.

Chromatography, High Pressure Liquid↗
PubMed1979

Enhanced chartreusin solubility by hydroxybenzoate hydrotropy.

The apparent aqueous solubility of the water-insoluble cytotoxic agent, chartreusin, was increased at neutral pH in the presence of hydroxybenzoates. Water molecules play an important role in the chartreusin conformation. Studies included solubility and spectral examinations. The weakest and strongest interactants with chartreusin were sodium benzoate and sodium trihydroxybenzoate, respectively, while the effect of mono- and dihydroxybenzoates was intermediate. A plane-to-plane orientation of chartreusin and the ligand molecules brought together by electrostatic and hydrophobic interactions is postulated. The dramatic chartreusin aqueous solubility increase relative to its aglycone, chartarin, under similar conditions was best rationalized by micellization.

Antibiotics, Antineoplastic↗
PubMed1978

Dissolution and absorption of the antineoplastic agent ellipticine.

Ellipticine, a poorly water-soluble alkaloid, is active in several experimental tumor systems. Marked solubility increases were produced by polyvinylpyrrolidone of varying molecular weights (10,000--160,000) and were optimal (approximately 13 mg/ml at 25 degrees) with polyvinylpyrrolidone mol. wt 10,000. Dissolution of ellipticine--polyvinylpyrrlidone (1:22 w/w) tablets in simulated gastric juice was superior to that of ellipticine hydrochloride polymers without affecting maximum dissolution at 37 degrees. Physiological disposition of ellipticine--polyvinylpyrrolidone was compared with that of the hydrochloride salt and ellipticine in suspension following oral administration at 250 mg/kg in fasted mice. In comparison to the suspension, ellipticine tissue levels were about threefold higher with polyvinylpyrrolidone or hydrochloride preparations. Antitumor activity of the three preparations was evaluated intraperitonneally and orally versus L-1210 leukemia. The optimal dose of ellipticine--polyvinylpyrrolidone and ellipticine hydrochloride was lower than that of the suspension and suggested improved absorption.

Administration, Oral↗
PubMed1978

Evaluation of some pharmaceutical aspects of intrathecal methotrexate sodium, cytarabine and hydrocortisone sodium succinate.

Methotrexate sodium, cytarabine and hydrocortisone sodium succinate were evaluated in three vehicles, Sodium Chloride Injection, USP, Lactated Ringer's Injection, USP, and Elliott's B solution, an artificial cerebrospinal fluid (CSF). Osmolarity values of all drug solutions studied were within 10% of normal human. No vehicle-related alterations in the stability of methotrexate or cytarabine were detected under simulated use conditions. However, the degradation of hydrocortisone sodium succinate was faster in Elliott's B solution than in the other vehicles. Principal differences among the vehicles involved electrolyte content, pH and buffer capacity. Elliott's B solution is similar to CSF in electrolyte composition and buffer capacity, and was the only vehicle to maintain the pH of dilute methotrexate and cytarabine solutions between 7.2 and 7.8. The significance of these in vitro data await a careful clinical study.

Chemistry, Pharmaceutical↗
PubMed1978

A simple method for the estimation of amygdalin in the urine.

A procedure for the estimation of D- and D,L-amygdalin in urine is described. Amygdalin is hydrolyzed by beta-glucosidase and base to benzaldehyde, glucose and cyanide. Benzaldehyde is extracted with methylene chloride and the ultraviolet (UV) absorbence determined at 243 nm. The response of human urine "spiked" with amygdalin was linear between 10 and 75 microgram/ml. Mice administered 100 mg/kg of amygdalin intravenously or orally excreted about 70 and 20% of the administered dose, respectively, over 96 hours. In each instance more than 96% of excreted drug equivalents were obtained within the first 24 hours.

Administration, Oral↗