Impact of Imaging Biomarkers and AI on Breast Cancer Management: A Brief Review

Breast cancer stands out as the most frequently identified malignancy, ranking as the fifth leading cause of global cancer-related deaths. The American College of Radiology (ACR) introduced the Breast Imaging Reporting and Data System (BI-RADS) as a standard terminology facilitating communication between radiologists and clinicians; however, an update is now imperative to encompass the latest imaging modalities developed subsequent to the 5th edition of BI-RADS. Within this review article, we provide a concise history of BI-RADS, delve into advanced mammography techniques, ultrasonography (US), magnetic resonance imaging (MRI), PET/CT images, and microwave breast imaging, and subsequently furnish comprehensive, updated insights into Molecular Breast Imaging (MBI), diagnostic imaging biomarkers, and the assessment of treatment responses. This endeavor aims to enhance radiologists' proficiency in catering to the personalized needs of breast cancer patients. Lastly, we explore the augmented benefits of artificial intelligence (AI), machine learning (ML), and deep learning (DL) applications in segmenting, detecting, and diagnosing breast cancer, as well as the early prediction of the response of tumors to neoadjuvant chemotherapy (NAC). By assimilating state-of-the-art computer algorithms capable of deciphering intricate imaging data and aiding radiologists in rendering precise and effective diagnoses, AI has profoundly revolutionized the landscape of breast cancer radiology. Its vast potential holds the promise of bolstering radiologists' capabilities and ameliorating patient outcomes in the realm of breast cancer management.

Utility of diffusion tensor imaging in differentiating benign from malignant hepatic focal lesions

OBJECTIVES

To assess the diagnostic accuracy of diffusion tensor imaging (DTI) in the characterization of hepatic focal lesions (HFLs) and compare it to diffusion-weighted imaging (DWI).

METHODS

Prospective analysis was done for 49 patients (23 male and 26 female) with 74 HFLs who underwent dynamic MRI, DWI, and DTI. Apparent diffusion coefficient (ADC) values from DWI, fractional anisotropy (FA) values, and mean diffusivity (MD) values from DTI were measured by two independent radiologists. HFLs were classified into benign and malignant HFLs; the latter were subdivided into HCC and non-HCC lesions. Binary logistic regression was performed to analyze the associations between the DTI parameters and the distinction of malignant lesions.

RESULTS

The ADC, MD, and FA at cutoff values of ≤ 1.17 × 10^-3 mm²/s, ≤ 1.71 × 10^-3 mm²/s, and > 0.29, respectively, are excellent discriminators for differentiating malignant and benign HFLs. The mean ADC and MD values of hemangiomas were significantly higher than HCC and non-HCC malignant lesions. In contrast, the mean FA values of hemangiomas were significantly lower than those of non-HCC malignant lesions and HCCs. The ADC and MD were very good discriminators at cutoff values of > 1.03 × 10^-3 mm²/s and > 1.12 × 10^-3 mm²/s, respectively. The FA at a cutoff value > 0.38 is an excellent discriminator for HCC versus non-HCC malignant lesions. Only FA value > 0.38 was a statistically significant independent predictor of HCC versus non-HCC lesions among the three parameters. There was an excellent inter-observer agreement with ICC > 0.9.

CONCLUSION

MD and FA of DTI are non-invasive, very good, and excellent discriminators superior to ADC measured by DWI for the differentiation of HFLs.

KEY POINTS

• The ADC, MD, and FA at cutoff values of ≤ 1.17 × 10^-3 mm²/s, ≤ 1.71 × 10^-3 mm²/s, and > 0.29, respectively, are excellent discriminators for differentiating malignant and benign HFLs. • The mean ADC and MD values of hemangiomas were significantly higher than those of HCC and non-HCC malignant lesions. In contrast, the mean FA values of hemangiomas were significantly lower than those of non-HCC malignant lesions and HCCs, respectively. • Multivariate regression analysis revealed that only FA value > 0.38 was a statistically significant independent predictor of HCC vs. non-HCC lesions. A lesion with FA > 0.38 has 34 times higher odds of being HCC rather than non-HCC lesions.

MO145: Chest CT Total Severity Score on Admission to Predict In-Hospital Mortality in Patients with Acute and Chronic Renal Impairment with COVID-19 Infection

BACKGROUND AND AIMS

COVID-19 is an infection that has spread widely and quickly over the world, resulting in a pandemic with substantial consequences for the sociopolitical environment and healthcare delivery systems. The aim of this study was to explore the clinical, laboratory characteristics and chest CT severity score in patients with renal impairment who died with COVID-19 infection.

METHOD

This retrospective study examined the electronic clinical and laboratory data of consecutive patients aged 18 years and older, with serum creatinine > 2 mg/dL who tested positive for COVID-19 and admitted to Mansoura University Hospital between June 2020 and May 2021. CT scans of the chest were retrospectively examined by one reviewer with 10 years’ experience in thoracic imaging for the following characteristics based on the Fleischner Society Nomenclature recommendations: ground-glass opacity (GGO), consolidation, nodules, crazy-paving pattern, subpleural lines, bronchial wall thickening, lymph node enlargement and pleural effusion.

 We attempted to measure the magnitude of the abnormalities by the total severity score to assess the severity of lung parenchymal involvement. The total severity score was primarily a numeric score that assessed the existence of GGOs, consolidation or mixed GGOs in each of the five lobes of both lungs. Each lobe will be rated from 0 to 4 points based on the percentage of the involved lobe: (0) = 0%, (1) = 1–25%, (2) = 26–50%, (3) = 51–75% or (4) = 76–100%. The overall score, which varies from 0 to 20, is the sum of the points from each lobe. Death events were collected, and the ROC curve analysis for CT severity score was used to determine the best cutoff that predict mortality.

RESULTS

Of a total 100 patients, 54 were males, with a mean age of 60 ± 15 years. Sixty patients died. Mortality was higher in those with acute renal impairment (P = .033) than chronic kidney disease. Non-survivors had higher respiratory rate (P = .000), C-reactive protein (CRP) (P = .003), ICU admission (P = .000), oxygen supply needs (P = .005), pulmonary consolidation (P = .000) and crazy paving pattern (P = .000). Furthermore, non-survivors had higher CT chest total severity score (P = .000).

 Univariate regression analysis showed increasing odds of in-hospital mortality associated with increased respiratory rate (OR 1.149, 95% CI 1.057–1.248, P = .001), total bilirubin (OR 2.532, 95% CI 1.099–5.836, P = .029), lactate dehydrogenase (OR 1.001, 95% CI 1.000–1.003, P = .018), CRP (OR 1.010, 95% CI 1.002–1.017, P = .012), invasive mechanical ventilation (OR 7.667, 95% CI 2.118–27.755, P = .002), predominant pattern of pulmonary consolidation (OR 21.714, 95% CI 4.799–98.261, P = .000) and high CT chest total severity score (OR 2.082, 95% CI 1.579–2.745, P = .000) . The optimum cut-off value of CT chest total severity score to predict in-hospital mortality was 8.5 with a sensitivity of 86.7% and a specificity of 87.5% (Figure 1).

CONCLUSION

In-hospital mortality is high in patients with renal impairment with COVID-19 infection especially those with acute renal impairment. High bilirubin, predominant pattern of pulmonary consolidation and CT chest total severity score are the most significant predictors of mortality in these patients. CT chest total severity score on admission ≥8.5 could effectively predict in-hospital mortality in these patients.

Comparison of chest CT severity scoring systems for COVID-19

PURPOSE

To compare the diagnostic performance and inter-observer agreement of five different CT chest severity scoring systems for COVID-19 to find the most precise one with the least interpretation time.

METHODS AND MATERIALS

This retrospective study included 85 patients (54 male and 31 female) with PCR-confirmed COVID-19. They underwent CT to assess the severity of pulmonary involvement. Three readers were asked to assess the pulmonary abnormalities and score the severity using five different systems, including chest CT severity score (CT-SS), chest CT score, total severity score (TSS), modified total severity score (m-TSS), and 3-level chest CT severity score. Time consumption on reporting of each system was calculated.

RESULTS

Two hundred fifty-five observations were reported for each system. There was a statistically significant inter-observer agreement in assessing qualitative lung involvement using the m-TSS and the other four quantitative systems. The ROC curves revealed excellent and very good diagnostic accuracy for all systems when cutoff values for detection severe cases were > 22, > 17, > 12, and > 26 for CT-SS, chest CT score, TSS, and 3-level CT severity score. The AUC was very good (0.86), excellent (0.90), very good (0.89), and very good (0.86), respectively. Chest CT score showed the highest specificity (95.2%) in discrimination of severe cases. Time consumption on reporting was significantly different (< 0.001): CT-SS > 3L-CT-SS > chest CT score > TSS.

CONCLUSION

All chest CT severity scoring systems in this study demonstrated excellent inter-observer agreement and reasonable performance to assess COVID-19 in relation to the clinical severity. CT-SS and TSS had the highest specificity and least time for interpretation.

KEY POINTS

• All chest CT severity scoring systems discussed in this study revealed excellent inter-observer agreement and reasonable performance to assess COVID-19 in relation to the clinical severity. • Chest CT scoring system and TSS had the highest specificity. • Both TSS and m-TSS consumed the least time compared to the other three scoring systems.

Preimaging and Postimaging of Graft and Flap in Head and Neck Reconstruction

Head and neck reconstructive surgical techniques are complex; now the microvascular free tissue transfer is the most frequently used. The postreconstruction imaging interpretation is challenging due to the altered anatomy and flap variability. We aim to improve radiologists' knowledge with diverse methods of flap reconstruction for an accurate appreciation of their expected cross-sectional imaging appearance and early detection of tumor recurrence and other complication.

A novel computer-aided diagnostic system for accurate detection and grading of liver tumors

Liver cancer is a major cause of morbidity and mortality in the world. The primary goals of this manuscript are the identification of novel imaging markers (morphological, functional, and anatomical/textural), and development of a computer-aided diagnostic (CAD) system to accurately detect and grade liver tumors non-invasively. A total of 95 patients with liver tumors (M = 65, F = 30, age range = 34–82 years) were enrolled in the study after consents were obtained. 38 patients had benign tumors (LR1 = 19 and LR2 = 19), 19 patients had intermediate tumors (LR3), and 38 patients had hepatocellular carcinoma (HCC) malignant tumors (LR4 = 19 and LR5 = 19). A multi-phase contrast-enhanced magnetic resonance imaging (CE-MRI) was collected to extract the imaging markers. A comprehensive CAD system was developed, which includes the following main steps: i) estimation of morphological markers using a new parametric spherical harmonic model, ii) estimation of textural markers using a novel rotation invariant gray-level co-occurrence matrix (GLCM) and gray-level run-length matrix (GLRLM) models, and iii) calculation of the functional markers by estimating the wash-in/wash-out slopes, which enable quantification of the enhancement characteristics across different CE-MR phases. These markers were subsequently processed using a two-stages random forest-based classifier to classify the liver tumor as benign, intermediate, or malignant and determine the corresponding grade (LR1, LR2, LR3, LR4, or LR5). The overall CAD system using all the identified imaging markers achieved a sensitivity of 91.8%±0.9%, specificity of 91.2%±1.9%, and F\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{1}$$\end{document}1 score of 0.91±0.01, using the leave-one-subject-out (LOSO) cross-validation approach. Importantly, the CAD system achieved overall accuracies of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$88\%\pm 5\%$$\end{document}88%±5%, 85%±2%, 78%±3%, 83%±4%, and 79%±3% in grading liver tumors into LR1, LR2, LR3, LR4, and LR5, respectively. In addition to LOSO, the developed CAD system was tested using randomly stratified 10-fold and 5-fold cross-validation approaches. Alternative classification algorithms, including support vector machine, naive Bayes classifier, k-nearest neighbors, and linear discriminant analysis all produced inferior results compared to the proposed two stage random forest classification model. These experiments demonstrate the feasibility of the proposed CAD system as a novel tool to objectively assess liver tumors based on the new comprehensive imaging markers. The identified imaging markers and CAD system can be used as a non-invasive diagnostic tool for early and accurate detection and grading of liver cancer.

An infarcted wandering spleen leading to a sigmoid volvulus presenting with acute large bowel obstruction: a case report

A wandering spleen is a very rare event characterised by the absence of the spleen in its anatomical position due to the hyperlaxity of its ligaments. We present a case of wandering spleen complicated by splenic vascular pedicle torsion, thrombosis and subsequent splenic infarction. Compression of the infarcted spleen on the rectosigmoid junction led to the development of a sigmoid volvulus, which presented as an acute large bowel obstruction. The patient underwent emergency laparotomy, splenectomy, sigmoid decompression and sigmoidopexy. After a follow-up period of two years, the volvulus had not recurred.

The adjunctive value of diffusion weighted imaging in diagnosis and follow up of uterovaginal diffuse B-cell lymphoma: A case report and literature review

BACKGROUND

Lymphoma of the female gynecologic tract is extremely rare. Typically, lymphoma is managed non surgically unlike other non-lymphomatous malignant tumors raising the importance to differentiate between both entities.

CASE REPORT

We describe the magnetic resonance imaging (MRI) features of a case of uterovaginal diffuse large B-cell lymphoma in a 50-year-old postmenopausal woman emphasizing Diffusion-Weighted Imaging (DWI) as a diagnostic and follow up tool. We reviewed the literature regarding the diagnostic methods for female genital lymphoma. Forty-five cases including our patient were reviewed with age range from 22 to 85 years. Vaginal bleeding was the most common presentation. The diagnosis was established by Papanicolaou smear, cervical biopsy (25/45), endometrial biopsy (6/45), vaginal biopsy (2/45), pelvic mass biopsy (2/45), iliac LN biopsy (1/45) and surgical diagnosis (8/45). Diffuse large B-cell lymphomas (DLBCL) constitute the vast majority of the cases (82%). The uterine cervix was involved at diagnosis in the majority of these cases (68%) while uterine body (42%) and vagina (28%) were less involved. Pelvic lymphadenopathy was found in 15 cases while extra genital lymphomatous infiltration in 13 cases. Sonographic findings were nonspecific while CT provided excellent data about extra-genital involvement. Thirteen cases underwent pelvic MRI that displayed superior detection of disease extension and parametric involvement. Diffusion restriction was reported only in one case without quantitative analysis of ADC map.

CONCLUSION

MRI shows unique features that help to differentiate uterovaginal lymphoma from the much more common carcinomas and discriminate post-operative changes from tumor recurrence. It exhibits a marked restricted diffusion pattern with lower ADC values than carcinomas and post-operative changes.

Multicentric adrenocorticotropic hormone -producing steroid cell tumor of the fallopian tube & broad ligament in a 15 year old girl

Steroid cell tumors occur usually in the ovaries with very few reported cases of extra-ovarian origin. Our patient was a fifteen year old female, complaining from secondary amenorrhea and voice deepening. Values of serum cortisol, DHEA, FSH & LH were normal. Serum Testosterone was elevated while ACTH-pm was markedly elevated. MRI described bilateral solid para-ovarian masses. Exploration revealed two bilateral tubal extraluminal cysts & a right broad ligament cyst which were all excised. Pathological examination led to the diagnosis of steroid cell tumor. Serum testosterone & ACTH returned to normal levels after surgery with subsequent regression of the virilizing symptoms. We can conclude that extra-ovarian steroid cell tumors are extremely rare. They are usually presented with virilizing symptoms and hormonal abnormalities. Surgery is the main line of treatment.

Metastatic colorectal carcinoma initially diagnosed by bone marrow biopsy: a case report and literature review

BACKGROUND

Colorectal carcinoma still represents a global health burden despite the advances in its management. The most common sites of distant metastasis from colorectal carcinoma are hepatic and pulmonary metastases while metastases are rarely reported to affect the bone marrow.

CASE PRESENTATION

We report a 33-year-old female patient who presented with fever of unknown origin, bone aches limited to the lower back and pelvis, and pancytopenia. She was diagnosed by a bone marrow biopsy as a case of metastatic rectosigmoid carcinoma. Serum tumor markers were within normal ranges; CT, MRI, and colonoscopy confirmed the presence of malignant rectosigmoid mass with bone and ovarian metastases.

CONCLUSION

Though being rare, bone marrow metastasis should be suspected in colorectal carcinoma cases with abnormalities in peripheral blood count.

Recurrent mandibular ameloblastoma in soft tissue and rib graft 17 years after initial presentation

BACKGROUND

Ameloblastoma is the commonest odontogenic tumour of epithelial origin with a high incidence for developing local recurrence. We present a patient who developed local recurrence in both soft tissue and bone graft 17 years after the initial presentation.

CASE PRESENTATION

A 75-year-old female with a previous history of right hemimandibulectomy and rib reconstruction for ameloblastoma in 1999 presented to our centre with a large cystic mouth floor swelling, biopsy from which revealed recurrent ameloblastoma. The patient underwent excision of the recurrent mass en bloc with the cystic swelling through oral and cervical approaches. The patient was discharged after 5 days with an uneventful postoperative course and with a free 2-year follow-up from further recurrence.

CONCLUSION

Ameloblastoma is a locally aggressive tumour for which wide local excision with adequate margins is the best management approach. Recurrence of ameloblastoma even after adequate resection is not uncommon, and its management is considered a surgical challenge. A very long time may pass between the initial presentation and the development of recurrence.

Axillary nodal metastasis in ovarian cancer: a report of three cases and review of literature

BACKGROUND

Ovarian cancer represents a major global health burden that is rarely associated with distant metastasis. Axillary lymph node metastasis from ovarian cancer is rare and is reported only in few case reports in literature.

CASE PRESENTATION

We report three cases of ovarian carcinoma associated with axillary lymph node metastasis as well as a brief literature review. The pathologic subtype in one case was malignant mixed Mullerian tumor, while the other two cases were high-grade serous ovarian carcinoma. Axillary nodal metastasis was reported as a synchronous event in one case, while it was reported as recurrence events in the other two cases.

CONCLUSION

Physicians should be aware of this uncommon mode of metastasis in ovarian cancer cases. Multi-disciplinary discussion is crucial in the management of these cases to offer them the best suitable treatment.

Male Breast Huge Malignant Phyllodes

Introduction: Phyllodes tumors are rare breast tumors. The best treatment is wide local excision with 1 cm safety margin unless metastatic. The three pathological types (benign, borderline and malignant were reported in men. Case presentation: A 73year-old male with huge left breast swelling extending from the clavicle to the left hypochondriac region. Core needle biopsy suggested malignant phyllodes tumor. Postcontrast CT revealed a huge mass seen at the left anterolateral chest wall measuring about (22 x 25 x 26 cm). Simple mastectomy was performed en bloc with the tumor. The microscopic examination led to the diagnosis of high grade malignant phyllodes. IHC showed diffuse positive vimentin, CD10 and negative CK in the neoplastic cells. The patient lost follow up for three months.Then he was presented with fungating local recurrence with bilateral metastatic pulmonary. The patient underwent palliative excision. After the second surgery, he was prepared for palliative chemoradiotherapy but the patient died one month later at home. Discussion and conclusions: Very few cases of phyllodes tumor were reported in men. Pathologically, phyllodes tumors are subdivided into three types: benign, borderline and malignant according to mitotic frequency, nature of margins, stromal growth, cellularity and atypia. Malignant phyllodes tumors tend to spread via hematological route mainly to the lung, then to the bone. Phyllodes tumors even benign type tend to recur even after complete excision with higher tendency for malignant cases. Wide local excision is the standard of care for phyllodes tumors with or without adjuvant radiotherapy in malignant lesions- with no proved value for chemotherapy or hormonal therapy.

Preoperative localization of sentinel lymph node in breast cancer patients by silver wire insertion or liquid charcoal injection guided by CT lymphography

Dual localization of SLN in breast cancer patients using isotope & dye is the best-approved modality with limitations such as high cost of radioactive materials, complex logistic preparations & scheduling issues, especially in developing countries. We investigated the feasibility & accuracy of a novel technique for SLN localization using silver wire insertion or liquid charcoal injection guided by CT lymphography. 120 patients with clinically node-negative breast cancer were enrolled. In the test group, SLN was localized using preoperative CTLG guided injection of liquid charcoal or by placing a 3 cm silver wire. In addition, intraoperative SLN mapping was performed using methylene blue dye followed by searching for the SLN localized by both methods. In the control group, SLN was localized by the blue dye only. Feasibility, accuracy, detection rates, and number of SLNs retrieved were reported as well as matching between the LN detected with the CTLG and that detected with the dye technique. SLN could be detected in 59 out of 60 patients (98.3%) in the test group and in 54 out of 60 patients (90%) in the control group (P = .057). In self-controlled analysis of the test group comparing CTLG only to dye only was significant (P = .050). Comparing charcoal to silver wire in detection was statistically insignificant (P = .5). This novel method can offer advantages which are as follows: being more accurate than the dye alone, saving operative time, abandoning complex logistic preparations for the radioisotope, and solving the problem of timing.

Intramammary Nodal Metastasis from Ovarian Cancer: A Case Report

Intramammary metastasis from ovarian cancer is rare. It is usually associated with poor prognosis. We present a 56-year-old female with advanced ovarian cancer in whom a metastatic intramammary lymph node was discovered after finishing the first line of neoadjuvant chemotherapy.

Papillary thyroid carcinoma in cervical lymph nodes with vanished thyroid gland after ablation of Graves' disease by radioactive iodine

Primary thyroid carcinoma after thyroid ablation by radioactive iodine is rare. We present a very rare condition of lateral apparent papillary thyroid carcinoma eight years after receiving radioactive iodine for thyrotoxicosis, which led to complete anatomical and functional involution of the thyroid gland.

A Totally Laparoendoscopic Approach for Low Rectal Cancer with Inguinal Nodal Metastasis

BACKGROUND AND AIMS

Isolated inguinal nodal metastasis from rectal cancer is rare with better oncological outcome in case of surgical resection.

METHODS

We report a rectal cancer case with inguinal nodal metastasis that was operated using a totally endoscopic approach. Laparoscopic intersphincteric resection was done for rectal cancer and video endoscopic inguinal lymphadenectomy (VEIL) for inguinal lymph nodes. The patient was presented to and managed in the Oncology Center, Mansoura University, Egypt.

RESULTS

The patient had an uneventful postoperative course with better outcome than open surgery.

CONCLUSIONS

Incorporation of minimally invasive approaches such as laparoscopy and VEIL in the management of inguinal nodal metastasis from rectal cancer can have a great impact on the patient's quality of life without affecting the oncologic outcome.

Small breast Schwannoma in an old female; a case report

Schwannoma is a usually benign peripheral nerve sheath tumor with rare breast incidence and few reported cases. We report a case which was presented to and managed in the Oncology center, Mansoura University in November 2017.

Determination of barnidipine in human serum and dog plasma by HPLC with electrochemical detection

Barnidipine is a 1,4-dihydropyridine calcium antagonist. HPLC was conducted on a polybutadiene coated alumina column using an alkaline mobile phase and an electrochemical detector to determine the content of this drug in serum and plasma. A good linear relationship between barnidipine concentration and peak height was found in 5-500 ng/ml with a correlation coefficient of 0.998. The detection limit was 1 ng/ml. The within-day and day-to-day variations were examined for control human serum. Relative standard deviation of within-day assay for serum spiked with 10 ng/ml barnidipine.HCl was 6.9% and the recovery was 104%. A pharmacokinetic study was made in which the time course of barnidipine in dog plasma was followed.

Utility of certain pi-acceptors for the spectrophotometric determination of some penicillins

Two simple and sensitive spectrophotometric methods are described for the determination of six penicillin derivatives. The methods are based on the reaction of these drugs as n-electron donors with either 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) as pi-acceptors, to give a highly coloured radical anion. The coloured products are quantified spectrophotometrically at 460 and 842 nm for DDQ and TCNQ, respectively. The optimization of the different experimental conditions is described. The interference from streptomycin sulphate and common degradation products was also studied. The proposed methods were applied successfully to the determination of the different penicillins investigated, either in pure or dosage forms, with good accuracy and precision. The results were compared with those given by the official United States Pharmacopeial XXI method.

Spectrophotometric methods for the determination of sulphathiourea

Three simple and sensitive spectrophotometric methods are described for the determination of sulphathiourea. The methods are based on the interaction of this thioamide with either iodine, tetracyanoethylene (TCNE) or copper nitrate to give the corresponding charge-transfer or metal-ion complexes, which can be measured at 363, 350 and 353 nm, respectively. In each case, a 1:1 complex was formed. Beer's law is obeyed for each procedure in a concentration range of 1-150 micrograms ml-1. The proposed procedures can be applied to the determination of sulphathiourea in its pharmaceutical formulations.

Spectrophotometric determination of some pharmaceutical amides through charge-transfer complexation reactions

A spectrophotometric method is described for the assay of fenpipramide hydrochloride, isopropamide iodide, trimethobenzamide hydrochloride, morphazinamide hydrochloride and tolazamide. The method is based on the formation of a charge-transfer complex between the drug as n-donor and iodine, a sigma-acceptor. The product exhibits absorption maxima at 295 and 365 nm; measurements are made at 365 nm for fenpipramide and at 295 nm for the other compounds. Beer's law is obeyed in a concentration range of 1-120 micrograms ml-1. The method is rapid, simple and sensitive and can be applied to the analysis of some commercial and laboratory prepared tablets without interference. A more detailed investigation of the complex was made with respect to its composition, association constant and free energy change.

Use of p-benzoquinone for the spectrophotometric determination of certain sulphonamides

A simple spectrophotometric method for the determination of 15 sulphonamides in bulk and in dosage forms is described. The method is based on the interaction of p-benzoquinone with sulphonamides in 0.1 M hydrochloric acid. The resulting chromophore is measured at 500 nm. The effects of different variables on colour development were established. Beer's law was obeyed in a concentration range of 10-50 micrograms ml-1. Results from the analysis of different sulphonamide tablets and ophthalmic solutions marketed locally were in good agreement with that of a reference method. Correlations between A1cm(1%) and certain physical parameters such as pKa values, characteristic volume Vx, and molecular connectivity indices 1X and 1Xv were determined by linear regression equations. A poor correlation was found between A1cm(1%) and bulkiness parameters but a highly significant negative correlation was obtained with apparent pKa values.