Gigantic laryngeal schwannoma: A case report with literature review.

Laryngeal schwannoma is a rare benign nerve sheath tumor that is slow growing. The diagnosis is made from a combination of clinical, radiological, and histopathological findings, and the main method of treatment is resection. We report a case of a 69-year-old presenting with a neck mass causing stridor, dysphagia, and orthopnea. CT of the neck showed an enhancing mass measuring 6.3 cm and extending superior to the larynx. Emergent tracheostomy and mass resection were performed, and histopathology and immunohistochemical findings were obtained from the specimen supporting schwannoma. In conclusion, while rare, schwannoma should always be considered as a differential diagnosis for a laryngeal mass. More studies are needed to assess the size and prognosis of the tumor.

Primary Adenosquamous Carcinoma of the Prostate.

Prostate cancer accounts for 29% of malignant diagnoses among men in the United States and is the second leading cause of death from cancer. Effective screening methods and improved treatment have decreased the mortality rate significantly. This decreased mortality rate, however, does not apply to all histologic variants. Adenosquamous carcinoma of the prostate is an extremely aggressive neoplasm with no current known curative therapy. It is often diagnosed after chemotherapy, radiation, or androgen deprivation therapy for traditional prostatic adenocarcinomas. Primary carcinomas of the prostate with squamous features include, but are not limited to, pure squamous cell carcinoma and adenocarcinoma mixed with squamous cell carcinoma (SCC). Important distinguishable clinical features of adenosquamous carcinoma include normal prostate-specific antigen (PSA) levels, even with advanced disease and osteolytic versus osteoblastic metastatic lesions in adenocarcinoma. Additional entities to consider in the differential diagnosis are squamous metaplasia of the prostate, secondary involvement of pure SCC, and urothelial carcinoma with squamous differentiation. Here, we present a de novo case of adenosquamous carcinoma in a 48-year-old man who rapidly developed extensive metastatic disease.

The success rate of small renal mass core needle biopsy and its impact on lowering benign resection rate.

BACKGROUND: Small renal mass (SRM) biopsy remains under-utilized due to stigma. Meanwhile, the alarmingly high benign findings in resected kidney masses highlight the need for improved preoperative diagnosis and patient selection. METHODS: The purpose of this study is to review the success rate of SRM biopsy and to evaluate its impact on patient management. A total of 168 percutaneous image-guided core needle biopsies (CNBs) of SRMs were retrieved at a tertiary academic center between 2015 and 2019. Subsequent treatment choices, side effects and outcomes were retrospectively reviewed. RESULTS: The diagnostic rate of CNB was 86.9%. Benign neoplasms accounted for a significant portion (14.3%) of SRM. Renal cell carcinomas (RCCs) were the most common diagnoses (69.6%) as expected. In biopsy-resection correlation, the positive predictive value of CNB was 100%. Tumor typing and subtyping by CNB were highly accurate, 100% and 98.3% respectively. Nuclear grading for clear cell RCC was accurate in 83.8% cases. The CNB results had significant impact on treatment. Most patients with RCCs underwent either resection (54.1%) or ablation (33.9%), in contrast to observation in benign neoplasms (90.5%). Most importantly, the benign resection rate (3.2%) in this series was much lower than the national average. CONCLUSION: CNB provided accurate diagnoses for the majority of SRMs and revealed benign diagnoses in a subset of clinically suspicious lesions. Employment of CNB in suspicious SRM may help avoid overtreatment for benign lesions.

An Anaplastic Thyroid Carcinoma of the Giant-Cell Type from a Mediastinal Ectopic Thyroid Gland.

Anaplastic thyroid carcinoma is a rare, aggressive form of thyroid carcinoma with a mean survival of less than 6 months. Ectopic thyroid tissue can be present in the mediastinum due to faulty embryogenesis with improper descent. Primary thyroid malignancies may arise from this ectopic tissue. A 90-year-old male with a history of prostatic adenocarcinoma, hypothyroidism, and occupational and therapeutic exposure to radiation presented with a rash on his chest. A review of the dermatopathology and excised mediastinal specimen revealed rare papillary foci that tested positive for thyroid markers from a background of poorly differentiated components. Molecular analysis confirmed a BRAF V600E mutation in the specimen. The final diagnosis was anaplastic thyroid carcinoma of the giant-cell type. Given the atrophic cervical thyroid tissue in the patient's neck with no evidence of previous surgery, this carcinoma was believed to arise from ectopic mediastinal tissue associated with cutaneous and bony metastasis. In conclusion, anaplastic thyroid carcinoma is an aggressive and rare thyroid malignancy that can arise from ectopic thyroid tissue in the mediastinum and should be considered in the differential diagnosis of primary undifferentiated mediastinal malignancies with bony involvement.

Endometrial Adenocarcinoma with Discordant Microsatellite Stability Status Treated with First-Line Pembrolizumab: A Case Report and Narrative Review.

BACKGROUND Microsatellite instability (MSI) is a hallmark of specific cancers and can be diagnosed using both tissue- and liquid-based approaches. When these tissue- and liquid-based approaches give differing results, they are known as discordant or being at variance. MSI-H tumors are well-researched candidates for treatment with programmed cell death protein 1 (PD-1) inhibitor-based immunotherapy, but the efficacy of immunotherapy in MSI-H discordant endometrial cancer, especially as first-line therapy, is not yet well documented in the literature. CASE REPORT A 67-year-old woman presented with a retroperitoneal mass positive for recurrent adenocarcinoma of endometrial origin. Her stage I endometrial adenocarcinoma 7 years ago demonstrated microsatellite stable (MSS) by immunohistochemical (IHC) stain and indeterminant due to insufficient tissue by Caris Next-Generation Sequencing (NGS). She then presented with a retroperitoneal mass that was MSI-H on IHC stain and Caris NGS, as well as MSI high on liquid biopsy @Guardant360 (@G360). The patient proceeded with pembrolizumab treatment 1 year ago and has sustained a complete clinical response at the time of writing. CONCLUSIONS Our case provides further evidence for the need to retest the microsatellite stability of metastatic sites, especially after a long disease-free survival. Here, we providing a literature review of case reports and a review of studies outlining discordance of testing modalities. Our case also highlights the importance of considering the use of immunotherapy as a first-line agent in patients who may have a poor ECOG performance status, as it can significantly improve their quality of life and reduce the number of adverse effects compared to chemotherapy.

Atypical Presentations of Collagenous Gastritis Mimicking Celiac Sprue.

Collagenous gastritis has been reported as a rare cause of nausea, diarrhea, weight changes, and early satiety in female patients. Here, we describe two women aged 43 and 71 years who presented with similar symptoms. Gastric biopsies from both individuals showed thickened, irregular subepithelial collagen bands (>10 µm). The pathogenesis of collagenous gastritis is poorly understood, but it may be the presenting symptom for many underlying autoimmune conditions. In particular, there is a well-established connection between collagenous disorders of the gastrointestinal tract and celiac sprue, Sjögren syndrome, and lymphocytic colitis; however, none of these conditions had been diagnosed in our patients. The older woman had incidentally discovered hypogammaglobinemia and IgA deficiency, whereas the younger woman suffered from fibromyalgia. Although a gluten-free diet and budesonide have been effective in some cases, there is no standardized therapy for collagenous gastritis. Our patients trialed diet modification and have required no additional medical interventions.

Cryoglobulinemia Leading to the Diagnosis of Low Grade Serous Ovarian Carcinoma.

We present the case of a 64-year-old female who was referred by her oncologist to benign hematology clinic for persistent asymptomatic cryoglobulinemia. Workup led to diagnosis of a rare low grade ovarian serous carcinoma. We briefly review the pathophysiology and clinical significance of cryoglobulinemia and the diagnosis and management of low grade serous ovarian carcinoma.

Atypical Cells in Peritoneal Cleft: A Pitfall in Diagnosis of Colorectal Adenocarcinoma.

Atypical cells in peritoneal clefts are usually either reactive mesothelial cells or pT4 colonic adenocarcinoma in colon specimen removed for primary colon cancer. However, rarely if ever are these atypical cells metastasis from other primary visceral malignancy due to "sac-like" anatomic structure of this area. We present a case where these atypical cells were determined to be metastasis of gynecological origin by judicious use of immunohistochemical stains. A final diagnosis of serous tubal intraepithelial carcinoma of right fallopian tube was diagnosed only after total abdominal hysterectomy bilateral salpingo-oophorectomy. To our knowledge, this is the first report of a serous tubal intraepithelial carcinoma presenting as stage 4 colonic adenocarcinoma. The importance of this interesting case is 2-fold. It highlights the peritoneal cleft as an anatomic region not often recognized or discussed as well as tumor presentation in this region. In addition, this example stresses the need for additional mesothelial markers in addition to WT-1 workup of atypical mesothelial proliferation.

Extended stability of intravenous acetaminophen in syringes and opened vials.

PURPOSE: The stability of i.v. acetaminophen beyond the manufacturer-recommended usage limit of six hours for opened vials was evaluated. METHODS: Intravenous acetaminophen (10 mg/mL) was obtained. Three identical samples of 100 mg (10 mL in a 10-mL syringe), 250 mg (25 mL in a 30-mL syringe), 500 mg (50 mL in a 60-mL syringe), 250 mg (25 mL in the original vial), and 900 mg (90 mL in original vial) were prepared. A 0.5-mL volume of each sample was withdrawn, diluted with mobile phase to an expected concentration of 50 µg/mL, and assayed in duplicate using high-performance liquid chromatography immediately after preparation and at 24, 48, 72, and 84 hours. The samples were visually inspected for any change in color, and pH was assessed at each time of analysis. The stability of the solutions was determined by calculating the percentage of the initial acetaminophen concentration remaining at each test hour. Stability was defined as the retention of at least 90% of the initial acetaminophen concentration. RESULTS: At least 99% of the initial concentration of acetaminophen remained in the original vials and polypropylene syringes throughout the 84-hour study period. There were no detectable changes in color, pH, visible microbial growth, or visible drug precipitation. CONCLUSION: Intravenous acetaminophen (10 mg/mL) was physically and chemically stable in a range of volumes for up to 84 hours in the opened vials and in polypropylene syringes at room temperature.

Stability of an extemporaneously prepared tadalafil suspension.

PURPOSE: The stability of an extemporaneously prepared tadalafil oral suspension was studied. METHODS: An oral suspension of tadalafil 5 mg/mL was prepared by thoroughly grinding 15 20-mg tadalafil tablets in a glass mortar. Thirty milliliters of Ora-Plus and 30 mL of Ora-Sweet were mixed and added to the powder to make a final volume of 60 mL. Three identical samples of the formulation were prepared and placed in 2-oz amber plastic bottles with child-resistant caps and stored at room temperature (23-25 °C). A 1-mL sample was withdrawn from each of the three bottles with a micropipette immediately after preparation and at 7, 14, 28, 57, and 91 days. After double dilution (1:10 and 0.1:5 v/v) to an expected concentration of 10 µg/mL with methanol and mobile phase, respectively, the samples were assayed in duplicate using stability-indicating high-performance liquid chromatography. The samples were visually examined for any color change and evaluated for pH changes on each day of analysis. Taste evaluation was performed at the beginning and end of the study. Stability was defined as the retention of at least 90% of the initial concentration. RESULTS: At least 99% of the initial tadalafil concentration remained throughout the 91-day study period. There were no detectable changes in color, odor, taste, and pH, and no visible microbial growth was observed in any sample. CONCLUSION: An extemporaneously prepared suspension of tadalafil 5 mg/mL in a 1:1 mixture of Ora-Plus and Ora-Sweet was stable for at least 91 days when stored in amber plastic bottles at room temperature.

Stability of an extemporaneously prepared thalidomide suspension.

PURPOSE: The short-term physical and chemical stability of an oral suspension of thalidomide 20 mg/mL was studied. METHODS: An oral suspension of thalidomide 20 mg/mL was prepared by emptying the contents of 12 100-mg thalidomide capsules into a glass mortar; 30 mL of Ora-Plus and 30 mL of Ora-Sweet were mixed and added to the thalidomide powder to make a final volume of 60 mL. Three identical samples of the formulation were prepared and placed in 2-oz amber plastic bottles with child-resistant caps and stored under refrigeration (3-5 °C). A 1-mL sample was withdrawn from each of the three samples with a micropipette immediately after preparation and at 7, 14, 21, 28, and 35 days. After further dilution to an expected concentration of 20 µg/mL with acetonitrile-methanol and then dilution with mobile phase, the samples were assayed in duplicate using stability-indicating high-performance liquid chromatography. Stability was determined by evaluating the percentage of the initial concentration remaining at each time point; stability was defined as the retention of at least 90% of the initial concentration of thalidomide. RESULTS: At least 92% of the initial thalidomide concentration remained throughout the 35-day study period. There were no detectable changes in color, odor, or pH and no visible microbial growth in any sample. CONCLUSION: An extemporaneously prepared suspension of thalidomide 20 mg/mL in a 1:1 mixture of Ora-Plus and Ora-Sweet was stable for at least 35 days when stored in 2-oz amber plastic bottles under refrigeration.

Stability of extemporaneously prepared glycopyrrolate oral suspensions.

PURPOSE: The stability of extemporaneously prepared glycopyrrolate 0.5-mg/mL suspensions was evaluated. METHODS: An oral suspension of glycopyrrolate 0.5 mg/mL was prepared by thoroughly grinding 30 1-mg tablets of glycopyrrolate in a glass mortar. Thirty milliliters of Ora-Plus and 30 mL of either Ora-Sweet or Ora-Sweet SF were mixed and added to the powder to make a final volume of 60 mL. Three identical samples of the formulation were prepared and placed in 2-oz amber plastic bottles with child-resistant caps and stored at room temperature (23-25 °C). A 1-mL sample was withdrawn from each of the three bottles with a micropipette immediately after preparation and 7, 15, 30, 60, and 90 days afterward. After further dilution to an expected concentration of 50 µg/mL with sample diluent, the samples were assayed in duplicate by stability-indicating high-performance liquid chromatography. The samples were visually examined for any color change and evaluated for pH on each day of analysis. Taste evaluations were performed at the beginning and end of the study. Stability was defined as the retention of at least 90% of the initial concentration. RESULTS: At least 95% of the initial glycopyrrolate remained throughout the 90-day study period in both preparations. There were no detectable changes in color, odor, taste, and pH, and no visible microbial growth was observed in any sample. CONCLUSION: Extemporaneously compounded suspensions of glycopyrrolate 0.5 mg/mL in a 1:1 mixture of Ora-Plus/Ora-Sweet or Ora-Plus/Ora-Sweet SF were stable for at least 90 days when stored in amber plastic bottles at room temperature.

Stability of extemporaneously prepared oxandrolone oral suspensions.

PURPOSE: The stability of extemporaneously prepared oxandrolone oral suspensions was studied. METHODS: Oxandrolone oral suspension (1 mg/mL) was prepared using oxandrolone tablets, Ora-Plus, and either Ora-Sweet or Ora-Sweet SF. Three identical samples of each formulation were prepared and stored in 2-oz amber plastic bottles with child-resistant caps at room temperature (23-25 °C). After thorough but gentle shaking by hand to prevent foaming, a 1-mL sample was withdrawn from each of the six bottles, diluted with mobile phase to an expected concentration of 200 µg/mL, and assayed in duplicate by injecting 5 µL into the high-performance liquid chromatography system immediately after preparation and at 7, 14, 35, 60, and 90 days. The samples were examined for any change in color or pH on each day of analysis. The stability of the suspensions was determined by calculating the percentage of the initial oxandrolone concentration remaining on each test day. Stability was defined as the retention of at least 90% of the initial oxandrolone concentration. RESULTS: At least 98% of the original oxandrolone concentration remained in both formulations at the end of the 90-day study period. There was no appreciable change in odor, taste, color, or pH. Both suspensions remained white in color and sweet with no aftertaste throughout the study period. The oxandrolone was easily resuspended with gentle shaking. CONCLUSION: Extemporaneously prepared suspensions of oxandrolone 1 mg/mL in 1:1 mixtures of Ora-Plus and either Ora-Sweet or Ora-Sweet SF were stable for at least 90 days when stored in 2-oz amber plastic bottles at room temperature.

Stability of an extemporaneous alcohol-free melatonin suspension.

PURPOSE: The stability of alcohol-free oral suspensions of melatonin 1 mg/mL, extemporaneously prepared from two commercially available melatonin tablet products, was studied. METHODS: Four 1-mg/mL melatonin suspensions were prepared. Formulations A and B contained 20 crushed 3-mg tablets of melatonin combined with a 1:1 mixture of Ora-Plus and either Ora-Sweet or Ora-Sweet SF to produce a volume of 60 mL. Formulations C and D were prepared by crushing 20 combination tablets containing melatonin 3 mg and pyridoxine hydrochloride 10 mg and then combining the powder with a 1:1 mixture of Ora-Plus and either Ora-Sweet or Ora-Sweet SF to produce a 60-mL volume. The suspensions were prepared in triplicate and stored at room temperature in amber plastic prescription bottles. Immediately after preparation and on days 7, 15, 30, 60, and 90, the samples were assayed in duplicate by stability-indicating high-performance liquid chromatography (HPLC). The samples were also evaluated for any changes in color, odor, and taste. RESULTS: HPLC analysis demonstrated that at least 94% of the initial melatonin concentration in formulations A and B, and at least 98% of that in formulations C and D, remained throughout the 90-day study period. Detectable changes in color, odor, or taste occurred in all of the formulations. CONCLUSION: Extemporaneously prepared, alcohol-free, 1-mg/mL suspensions of melatonin and melatonin-pyridoxine hydrochloride in a 1:1 mixture of Ora-Plus and either Ora Sweet or Ora Sweet SF were stable for at least 90 days when stored in 2-oz amber plastic bottles at room temperature.

Airway-rehydrating agents for the treatment of cystic fibrosis: past, present, and future.

OBJECTIVE: To review and evaluate airway-rehydrating agents used for the treatment of cystic fibrosis (CF). DATA SOURCES: Literature was retrieved through MEDLINE (1977-August 2010), Cochrane Library, and International Pharmaceutical Abstracts (1977-August 2010). Search terms used included hypertonic saline, inhaled mannitol, denufosol, Moli1901, lancovutide, and cystic fibrosis. Reference citations from selected articles were reviewed. STUDY SELECTION AND DATA EXTRACTION: All articles published in English identified from the data sources were evaluated for inclusion. Clinical trials in humans and relevant review articles were evaluated for each airway-rehydrating agent. DATA SYNTHESIS: Use of airway-rehydrating agents for the treatment of CF is an expanding area. Hypertonic saline (7% NaCl) is currently the only commercially available airway-rehydrating agent recommended for chronic therapy in patients with CF and is being evaluated in younger patients. Inhaled mannitol is an investigational dry-powder inhalation agent that improves mucus clearance in a similar manner to hypertonic saline and produced a statistically significant increase in forced expiratory volume in 1 second in a Phase 3 trial. Denufosol, a P2Y(2) agonist, rehydrates the airway surface liquid bypassing the basic CF transmembrane conductance regulator (CFTR) protein defect. It produces improvement in pulmonary function and is being further evaluated in a Phase 3 trial. Lancovutide (Moli1901) is an investigational agent in early-phase trials that activates a calcium-dependent chloride channel, allowing chloride to enter the airway. CONCLUSIONS: Hypertonic saline is the primary airway-rehydrating agent used in the treatment of CF. Inhaled mannitol may become an alternative to hypertonic saline since it is faster and easier to administer. It remains unclear whether denufosol and lancovutide will be synergistic or antagonistic with hypertonic saline. Both agents have a unique mechanism of action that bypasses the basic CFTR defect.

Stability of extemporaneously prepared acetylcysteine 1% and 10% solutions for treatment of meconium ileus.

PURPOSE: The stability of extemporaneously prepared acetylcysteine 1% and 10% solutions for treatment of meconium ileus was evaluated. METHODS: Acetylcysteine 1% (10-mg/mL) and 10% (100-mg/mL) solutions were prepared by mixing 3 and 10 mL, respectively, of commercially available 20% acetylcysteine solution with a sufficient quantity of bacteriostatic 0.9% sodium chloride for injection to make a final volume of 60 mL. Three identical samples of each concentration were prepared, placed in 2-oz amber plastic prescription bottles, and stored at 20-25 °C. Samples were assayed in duplicate using high-performance liquid chromatography and inspected for changes in color, odor, and pH immediately after preparation and at 7, 14, 30, 60, and 90 days. Stability was defined as retention of at least 90% of the initial concentration. RESULTS: At least 90% of the initial concentration of acetylcysteine was retained in both formulations for 60 days. No appreciable change from the initial pH occurred in the acetylcysteine 1% or 10% solution during the first 60 days, but there was a notable change in pH after 90 days in both formulations. Neither solution was stable at day 90. There was no detectable change in color at 90 days; however, the odor of hydrogen sulfide was more pungent than on previous study days. CONCLUSION: Extemporaneously prepared solutions of acetylcysteine 1% (10 mg/mL) and 10% (100 mg/mL) prepared with bacteriostatic 0.9% sodium chloride for injection were stable for at least 60 days when stored in plastic amber bottles at room temperature.

Stability of an extemporaneously prepared clopidogrel oral suspension.

PURPOSE: The stability of an extemporaneously prepared clopidogrel oral suspension was studied. Methods Clopidogrel oral suspension (5 mg/mL) was prepared using clopidogrel bisulfate tablets, Ora-Plus, and Ora-Sweet. Six 2-oz samples were prepared; three were stored at room temperature and three under refrigeration. One milliliter was withdrawn from each sample, diluted to 10 mL with methanol, and exposed to high-frequency sound waves in a water bath to ensure complete dissolution of clopidogrel. A 300-microL sample was then withdrawn, diluted with mobile phase to an expected concentration of 15 microg/mL, and assayed in duplicate using high- performance liquid chromatography immediately after preparation and at 7, 14, 28, and 60 days. The stability of the clopidogrel suspension was determined by calculating the percentage of the initial concentration remaining on each test day. Stability was defined as retention of at least 90% of the initial concentration. RESULTS: At least 97% of the initial clopidogrel concentration remained throughout the 60-day study period, regardless of storage conditions. There were no detectable changes in color, odor, taste, or pH and no visible microbial growth in any sample. The preparation was palatable, with a slightly gritty consistency and a slightly bitter aftertaste; the bitterness intensified slightly between 28 and 60 days but remained fairly mild. CONCLUSION: Extemporaneously compounded suspensions of clopidogrel, 5 mg/mL, in a 1:1 mixture of Ora-Plus and Ora-Sweet were stable for at least 60 days when stored in amber plastic bottles at room temperature and under refrigeration.

Stability of extemporaneously prepared rifaximin oral suspensions.

PURPOSE: The stability of extemporaneously prepared rifaximin oral suspensions was studied. METHODS: An oral suspension of rifaximin 20 mg/mL was prepared by thoroughly grinding six 200-mg tablets of rifaximin in a glass mortar. Thirty milliliters of Ora-Plus and 30 mL of either Ora-Sweet or Ora-Sweet SF were mixed and added to the powder to make a final volume of 60 mL. Three identical samples of each formulation were prepared and placed in 2-oz amber plastic bottles with child-resistant caps and were stored at room temperature (23-25 degrees C). A 1-mL sample was withdrawn from each of the six bottles with a micropipette immediately after preparation and at 7, 15, 30, and 60 days. After further dilution to an expected concentration of 20 microg/mL with mobile phase, the samples were assayed in duplicate using stability-indicating high-performance liquid chromatography. The samples were visually examined for any color change and pH was tested on each day of analysis. Stability was determined by evaluating the percentage of the initial concentration remaining at each time point and defined as retention of at least 90% of the initial concentration of rifaximin. RESULTS: At least 99% of the initial rifaximin remained throughout the 60-day study period in both preparations. There were no detectable changes in color, odor, taste, or pH and no visible microbial growth in any sample. CONCLUSION: Extemporaneously prepared suspensions of rifaximin 20 mg/mL in 1:1 mixtures of Ora-Plus with either Ora-Sweet or Ora-Sweet SF were stable for at least 60 days when stored in 2-oz amber plastic bottles at room temperature.

Stability of extemporaneously prepared moxifloxacin oral suspensions.

PURPOSE: The stability of extemporaneously prepared moxifloxacin oral suspensions was studied. METHODS: An oral suspension of moxifloxacin 20 mg/mL was prepared by thoroughly grinding three 400-mg tablets of moxifloxacin in a glass mortar. Thirty milliliters of Ora-Plus and 30 mL of either Ora-Sweet or Ora-Sweet SF were mixed and added to the powder to make a final volume of 60 mL. Three identical samples of each formulation were prepared and placed in 2-oz amber plastic bottles with child-resistant caps and were stored at room temperature (23-25 degrees C). A 1-mL sample was withdrawn from each of the six bottles with a micropipette immediately after preparation and at 7, 14, 28, 60, and 90 days. After further dilution to an expected concentration of 8 microg/ mL with sample diluent, the samples were assayed in duplicate by stability-indicating high-performance liquid chromatography. Stability was defined as the retention of at least 90% of the initial concentration. RESULTS: At least 99% of the initial moxifloxacin remained throughout the 90-day study period in both preparations. There were no detectable changes in color, odor, taste, and pH and no visible microbial growth in any sample. CONCLUSION: Extemporaneously compounded suspensions of moxifloxacin 20 mg/mL in a 1:1 mixture of Ora-Plus and Ora-Sweet or Ora-Sweet SF were stable for at least 90 days when stored in 2-oz amber plastic bottles at room temperature.

Stability of metoprolol tartrate injection 1 mg/mL undiluted and 0.5 mg/mL in 0.9% sodium chloride injection and 5% dextrose injection.

PURPOSE: The stability of metoprolol tartrate injection 1 mg/mL undiluted and 0.5 mg/mL in 0.9% sodium chloride injection and 5% dextrose injection was studied. METHODS: Sample set A contained 50 mL of Metoprolol Tartrate Injection, USP, 1 mg/mL transferred directly from the vials. Sample set B contained 50 mL of metoprolol 0.5 mg/mL diluted with 0.9% sodium chloride injection, and sample set C contained 50 mL of metoprolol 0.5 mg/mL diluted with 5% dextrose. All samples were prepared in triplicate and stored at room temperature. The stability of the samples was analyzed in duplicate using stability-indicating high-performance liquid chromatography immediately after preparation and at 6, 12, 18, 24, and 30 hours. The samples were assessed for pH and inspected for color and visible precipitation changes. The stability of metoprolol was determined by evaluating the percentage of the initial concentration remaining at each time interval. Stability of the product was defined as retention of 90% of the initial concentration. RESULTS: The mean +/- S.D. initial concentration in sample sets A, B, and C was 1.006 +/- 0.009 mg/mL, 0.498 +/- 0.002 mg/mL, and 0.499 +/- 0.002 mg/mL, respectively. Throughout the 30-hour study period, at least 99% of the initial concentration of metoprolol tartrate remained in all three preparations at all time points. No appreciable changes in pH occurred. No changes in color and no visible precipitate or microbial growth were detected. CONCLUSION: Metoprolol tartrate injection 1 mg/mL undiluted and 0.5 mg/mL in 0.9% sodium chloride injection and 5% dextrose injection were stable at room temperature for at least 30 hours.