Compatibility and activity of aldesleukin (recombinant interleukin-2) in presence of selected drugs during simulated Y-site administration: evaluation of three methods.

The compatibility and biological activity of aldesleukin (a form of recombinant interleukin-2) in the presence of selected i.v. drugs during simulated Y-site administration was studied. Five milliliters of aldesleukin 33,800 IU/mL in 5% dextrose injection was mixed in glass test tubes with 5 mL of each of 19 i.v. drugs prepared at concentrations used in routine clinical practice. The compatibility of the combinations was assessed by visual examination and spectrophotometry at 0, 0.5, 1, and 2 hours after preparation, and bioassays were conducted to determine the activity of aldesleukin in the combinations. Lorazepam was the only drug visually incompatible with aldesleukin. All the secondary drugs were spectrophotometrically compatible with aldesleukin. However, the bioassays showed that the following drugs reduced the activity of aldesleukin: ganciclovir sodium, lorazepam, pentamidine isethionate, prochlorperazine edisylate, and promethazine hydrochloride. Thus, aldesleukin became less biologically active when combined with four drugs for which visual examination suggested compatibility and when combined with five drugs for which spectrophotometry indicated compatibility. Aldesleukin 33,800 IU/mL in 5% dextrose injection lost significant biological activity in the presence of prochlorperazine edisylate, promethazine hydrochloride, lorazepam, ganciclovir sodium, and pentamidine isethionate during simulated Y-site administration. Visual assessment and spectrophotometry may not be valid methods for assessing possible changes in the biological activity of aldesleukin when combined with other agents.

USP perspectives on particle contamination of injectable products.

It is widely recognized that the level of particulate matter in an injectable product is one measure of quality, directly reflecting the success with which the manufacturer applies good quality control. The current USP XXII 1990 limits for particulate matter derived from knowledge that goes back to the 1970s but does not reflect the quality of the product available today. This presentation will discuss the purpose and background of proposed new limits intended to be adopted in the USP 23 revision cycle. The limits tests are structured in two stages for both Large-Volume and Small-Volume Injections, effectively employing an improved light obscuration method as a screening procedure. Product which fails this stage is then evaluated by a second stage, filtration and microscopic examination using a considerably improved procedure in which all of the container contents are sampled (or pooled to 25 mL) and the filter examined episcopically.

Patient-interactive computer system for obtaining medication histories.

A portable, patient-interactive computerized system for obtaining medication histories is described. A comprehensive interview script modeling pharmacist-conducted medication-history interviews was written in lay language. The script contains sections on demographics, current medical conditions, medication regimen, medication compliance, symptoms, allergy history, dietary history, psychosocial history, and occupational and environmental exposure; it also asks the patient to evaluate the system. Some of the information requested is often not obtained by physicians during the history and physical examination. A program that conducts the interview by processing a computerized version of the script was developed with Microsoft QuickBASIC. The program was designed to be run on a personal computer microprocessor so that an interview can be conducted virtually anywhere by using a desktop or laptop computer. Summary reports suitable for inclusion in the medical record are generated after each interview. Patients using the system took an average of 40 minutes to complete an interview. They entered data easily and accurately, and they gave the system a high overall rating. The medication-history interviewing system described produces useful, comprehensive, and consistent reports and requires about the same amount of time to conduct an interview as a human interviewer.

Development of a questionnaire for detecting potential adverse drug reactions.

OBJECTIVE: To develop a comprehensive list of symptoms categorized by body system as part of a questionnaire for detecting potential adverse drug reactions. DATA SOURCES: A preliminary list of symptoms in lay terminology was extracted from the "Side Effects" section of all drug monographs contained in the United States Pharmacopeia Dispensing Information (USP DI) computerized database (Volume II, Advice for the Patient) using natural language processing software. The list was sorted alphabetically and duplicate terms were eliminated. Symptoms were then categorized by body system or anatomic region. A preferred term for each symptom was selected when multiple synonyms and related words were listed. Finally, all of the symptom terms were incorporated into a thesaurus from which the questionnaire was derived. RESULTS: The questionnaire will be used as part of a computer-assisted interview, developed to solicit information from patients regarding their medication regimens and to systematically query them regarding the presence of salient symptoms or complaints. The computer system will eventually interface with the USP DI database to identify drugs from a patient's regimen that may be associated with adverse symptoms. The symptom thesaurus will provide the link to the USP DI database. Preliminary experience with the questionnaire in a limited number of patients has been encouraging. CONCLUSIONS: The questionnaire can assist clinicians in identifying drug-related symptoms including unreported adverse clinical effects of newly marketed or investigational therapeutic agents. When the questionnaire is computerized and linked to a comprehensive database, it can be more widely used to alert healthcare providers of potential adverse drug reactions that may otherwise go undetected.

Stability of zidovudine in 5% dextrose injection and 0.9% sodium chloride injection.

The stability of zidovudine at a concentration of 4 mg/mL in 5% dextrose injection and 0.9% sodium chloride injection in polyvinyl chloride infusion bags stored at room and refrigerated temperatures for up to eight days was studied. Zidovudine was diluted in 5% dextrose injection and in 0.9% sodium chloride injection to a concentration of 4 mg/mL. Six admixtures were prepared with each diluent; three were stored at room temperature (25 +/- 1 degree C) and three were refrigerated (4 +/- 1 degree C). At 0, 3, 6, 24, 48, 72, and 192 hours, 2-mL aliquots were removed. One milliliter of each aliquot was diluted to a zidovudine concentration of approximately 40 micrograms/mL and assayed in duplicate by a stability-indicating high-performance liquid chromatographic method. Visual inspection was performed at each sampling time for precipitation, turbidity, color change, and gas formation. Sample pH was recorded at 0 and 192 hours. In all admixtures, more than 97% of the initial zidovudine concentration remained throughout the study period. No visual or pH changes were observed. Zidovudine 4 mg/mL in admixtures with 5% dextrose injection or 0.9% sodium chloride injection stored in polyvinyl chloride infusion bags was stable for up to 192 hours (eight days) at room temperature and under refrigeration.

Liability and new drug studies. Informed consent and clinical trials at the National Institutes of Health.

The liability risk in carrying out clinical trials can be severely affected if the informed consent process is poorly carried out. A poorly informed patient could prematurely drop out of a costly study. Worse yet, if the patient discovers that information is withheld, the patient could sue the sponsor, physician investigator, or IRB and hold them liable, though this is unlikely for investigational drug studies. These costs can be avoided by making sure the clinical trial is properly carried out according to strict federal regulations. It is also critical that clinicians keep the research participant informed on an ongoing basis. The chain of command is vital: The monitor informs the sponsor, the sponsor in turn informs the investigator, and the investigator in turn informs the patient of any new treatment information that may affect his willingness to stay in the trial. Finally, wherever the clinical trial is conducted, it should conform with the ethical principles outlined in the Declaration of Helsinki or with the latest regulations of that country--whichever guidelines provide the greater protection for the patient.

Stability of concentrated trimethoprim-sulfamethoxazole admixtures.

The stability of trimethoprim-sulfamethoxazole (TMP-SMX) at various concentrations in 5% dextrose injection or 0.9% sodium chloride injection was studied. Appropriate volumes of TMP-SMX formulation (80 mg TMP and 400 mg SMX/5 mL) were mixed with 5% dextrose injection or 0.9% sodium chloride injection to provide dilutions of 1:25 v/v, 1:20 v/v, 1:15 v/v, and 1:10 v/v. Aliquots were removed at 0, 0.5, 1, 2, 4, 8, 14, 24, and 48 hours and filtered. The pH of the samples was determined, and the samples were assayed for trimethoprim and sulfamethoxazole content by high-performance liquid chromatography. Admixtures were visually inspected for precipitate before each sample was removed. The concentration of SMX in all admixtures did not change during the study period. The stability of TMP was dependent on concentration and vehicle. At a 1:25 v/v dilution, TMP was stable for 48 hours in 5% dextrose injection and 0.9% sodium chloride injection. At a 1:20 v/v dilution, TMP was stable for 24 hours in 5% dextrose injection and 14 hours in 0.9% sodium chloride injection. At a 1:15 v/v dilution, TMP was stable for four hours in 5% dextrose injection and two hours in 0.9% sodium chloride injection. At a 1:10 v/v dilution, TMP was stable for one hour in 5% dextrose injection and 0.9% sodium chloride injection. Concentrated solutions of TMP-SMX should be prepared in 5% dextrose injection, infused within one hour of preparation, and visually inspected for precipitation before and during infusion.

Effects of simulated facility-design changes on outpatient pharmacy efficiency.

The potential effects of using the Baker drug counter or the Systamodule pharmacy fixture, or both, on the efficiency of the current outpatient pharmacy system at the National Institutes of Health were evaluated by computer simulation. It was hypothesized that the use of these two devices would reduce (1) the prescription-filling time (RxFT) and (2) the distance traveled (DT) by pharmacists in filling individual prescriptions. The sample used was 20% of two weeks' prescriptions, randomly selected. All theoretical estimations of RxFT were done by a computer program; DT was calculated based on measurements from the architect's schematic drawings. The effect of the application of the Baker drug counter alone, the Systamodule pharmacy fixture alone, and the Baker drug counter in combination with the Systamodule pharmacy fixture was to reduce the prescription-filling time by 0.123, 0.159, and 0.280 minutes per prescription, respectively. The average DT per prescription, 102 feet, was identical in the current NIH pharmacy and with use of the Baker counter. It was reduced by 86.3% (to 14 feet) with use of the Systamodule feature, both alone and in combination with the Baker counter. The use of the Baker drug counter and the Systamodule together promises improved efficiency of the prescription dispensing operation.

Long-term stability of aqueous solutions of luteinizing hormone-releasing hormone assessed by an in vitro bioassay and liquid chromatography.

The stability of aqueous solutions of luteinizing hormone-releasing hormone (LHRH) after extended storage at various temperatures was investigated using a newly developed HPLC assay and an in vitro dispersed pituitary cell culture bioassay. Good correlations were obtained between the potency obtained by HPLC and bioassay in samples stored at 37 degrees C or subjected to different stress conditions. No significant decrease in activity of LHRH was observed in aqueous solutions stored at 37 degrees C for up to 10 weeks, at 4 degrees C for 2 years, or subjected to repeated freezing and thawing for 5 d. Heating to 60 degrees C in sterile pH 9.0 buffer up to 11 d and storage at ambient temperature in nonsterile solution for 4 months produced well-distinguished degradation products and a decrease in potency. It is concluded that sterile aqueous solutions of LHRH are stable for at least 10 weeks at 37 degrees C and, thus, could be reliably used for chronic administration when long-term stability at body temperature is important.

Quantitation of flupirtine and its active acetylated metabolite by reversed-phase high-performance liquid chromatography using fluorometric detection.

A simple, selective and sensitive procedure is described for the quantitation of flupirtine maleate (FLU) and its active acetylated metabolite (Met. 1) in plasma and urine. Using a 0.5-ml sample, a sensitivity of 10 ng/ml is easily achieved with a reversed-phase octadecylsilane (C18) column, and a high-performance liquid chromatographic system with fluorescence detection. Quantitation from plasma involves addition of an internal standard, protein precipitation with acetonitrile and a sample concentrating step, while for urinalysis the samples are taken through a single extraction with methylene chloride. Analytical recoveries of FLU and Met. 1 from plasma averaged greater than or equal to 95%, while from urine only 60 and 50%, respectively, could be recovered. The overall, inter- and intra-day variability for both FLU and Met. 1 averaged 6, 5 and 3%, in plasma, respectively. Standard calibration plots in plasma were linear (r greater than or equal to 0.99) for FLU (range: 0.01-10.0 micrograms/ml) and Met. 1 (range: 0.5-25 micrograms/ml) over the extended range. A slightly modified elution system was employed for quantitation of FLU and Met. 1 in urine.

Disposal of antineoplastic wastes at the National Institutes of Health.

The process of developing disposal guidelines for antineoplastic wastes at the National Institutes of Health (NIH) is described. Because of the large volume of hazardous wastes generated, NIH must comply with Environmental Protection Agency (EPA) guidelines for disposal. Seven antineoplastic agents are defined by EPA as hazardous wastes. Because of the similar toxicities and pharmacologic drugs, NIH officials elected to dispose of all such agents as hazardous wastes. Available options are presented. The NIH procedure divides antineoplastic wastes into trace- and bulk-contaminated categories. Trace-contaminated wastes contain minimal or trace amounts of drugs and are disposed of by one-site incineration. Bulk-contaminated materials (defined as intravenous solutions or containers whose contents weigh more than 3% of the capacity of the container) are disposed of by land internment and incineration at EPA-approved sites. Syringes and i.v. bottles containing antineoplastic drugs are labeled with bright red-orange labels instructing personnel to return the materials to the pharmacy for disposal. General decision-making procedures for other institutions are recommended.

Quantitation of testolactone and 4,5-dihydrotestolactone in plasma and urine using high-performance liquid chromatography.

A rapid, sensitive, and selective assay is described for the quantitation of both testolactone and its recently identified metabolite, 4,5-dihydrotestolactone, in plasma and urine using high-performance liquid chromatography. The procedure includes a methylene chloride extraction prior to chromatography and quantitation using peak height ratios (ultraviolet absorbance detection, 242 nm) of testolactone and 4,5-dihydrotestolactone to the internal standard, testosterone. A sensitivity of 20 ng/ml for both testolactone and 4,5-dihydrotestolactone is easily achieved using only 0.5 ml of sample. Mean recoveries for testolactone and its metabolite are 95.0% and 81.8%, respectively, and the mean coefficient of variation of the procedure is 3.5% for the drug and 7.1% for the metabolite. This method is currently being used to study the pharmacokinetics of testolactone and 4,5-dihydrotestolactone in male patients. A steady-state plasma concentration versus time profile from a representative patient is included.