Preparation and in vitro evaluation of meloxicam-loaded PLGA nanoparticles on HT-29 human colon adenocarcinoma cells.

CONTEXT: The inhibitors of cyclooxygenase (COX)-2 play an important role in cancer chemoprevention. Certain COX-2 inhibitors exert antiproliferative and pro-apoptotic effects on cancer cells. OBJECTIVE: In this study, meloxicam, which is an enolic acid-type preferential COX-2 inhibitor, was encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) to maintain local high concentration, and its efficacy was determined. METHODS: NPs were prepared by using salting-out and emulsion-evaporation steps. Meloxicam-loaded NP formulations were evaluated with respect to the drug loading, particle size, polydispersity index, zeta potential, drug release rate, and residual poly(vinyl alcohol) (PVA) percentage. The effects of PLGA and PVA molecular weight variations on the physicochemical properties of NPs were investigated. Stability of meloxicam in NPs was assessed over 3 months. COX-2 expressing human colon adenocarcinoma cell line HT-29 was used in cellular uptake and viability assays. RESULTS: NPs had a spherical shape and a negative zeta potential, and their size ranged between 170-231 nm with a lower polydispersity index. NPs prepared with high molecular weight PLGA were shown to be physically stable over three months at 4°C. The increase in molecular weight of the polymer and emulsifier reduced the in vitro release rate of meloxicam from NPs. Meloxicam-loaded NPs showed cytotoxic effects on HT-29 cells markedly at 800 µM. Cancer cells had high uptake of coumarin-6-loaded NPs. CONCLUSION: The PLGA NPs developed in this study can be a potentially effective drug delivery system of meloxicam for the treatment of colon cancer.

Treatment outcomes of bladder stones in children with intact bladders in developing countries: A systematic review of >1000 cases on behalf of the European Association of Urology Bladder Stones Guideline panel.

INTRODUCTION: Bladder stones (BS) are still endemic in children in developing nations and account for a high volume of paediatric urology workload in these areas. The aim of this systematic review is to comparatively assess the benefits and risks of minimally invasive and open surgical interventions for the treatment of bladder stones in children. METHODS: This systematic review was conducted in accordance with Cochrane Guidance. Database searches (January 1970- March 2021) were screened, abstracted, and assessed for risk of bias for comparative randomised controlled trials (RCTs) and non-randomised studies (NRSs) with >10 patients per group. Open cystolithotomy (CL), transurethral cystolithotripsy (TUCL), percutaneous cystolithotripsy (PCCL), extracorporeal shock wave lithotripsy (ESWL) and laparoscopic cystolithotomy (LapCL) were evaluated. RESULTS: In total, 3040 abstracts were screened, and 8 studies were included. There were 7 retrospective non-randomised studies (NRS's) and 1 quasi-RCT with 1034 eligible patients (CL: n=637, TUCL: n=196, PCCL: n=138, ESWL: n=63, LapCL n=0). Stone free rate (SFR) was given in 7 studies and measured 100%, 86.6%-100%, and 100% for CL, TUCL and PCCL respectively. CL was associated with a longer duration of inpatient stay than PCCL and TUCL (p<0.05). One NRS showed that SFR was significantly lower after 1 session with outpatient ESWL (47.6%) compared to TUCL (93.5%) and CL (100%) (p<0.01 and p<0.01 respectively). One RCT compared TUCL with laser versus TUCL with pneumatic lithotripsy and found that procedure duration was shorter with laser for stones <1.5cm (n=25, p=0.04). CONCLUSION: In conclusion, CL, TUCL and PCCL have comparable SFRs but ESWL is less effective for treating stones in paediatric patients. CL has the longest duration of inpatient stay. Information gathered from this systematic review will enable paediatric urologists to comparatively assess the risks and benefits of all urological modalities when considering surgical intervention for bladder stones.

Ethylcellulose-based matrix-type microspheres: influence of plasticizer RATIO as pore-forming agent.

In this study, ethylcellulose (EC)-based microsphere formulations were prepared without and with triethyl citrate (TEC) content of 10% and 30% by water-in-oil emulsion-solvent evaporation technique. Diltiazem hydrochloride (DH) was chosen as a hydrophilic model drug and used at different drug/polymer ratios in the microspheres. The aim of the work was to evaluate the influence of plasticizer ratio on the drug release rate and physicochemical characteristics of EC-based matrix-type microspheres. The resulting microspheres were evaluated for encapsulation efficiency, particle size and size distribution, surface morphology, total pore volume, thermal characteristics, drug release rates, and release mechanism. Results indicated that the physicochemical properties of microspheres were strongly affected by the drug/polymer ratio investigated and the concentration of TEC used in the production technique. The surface morphology and pore volume of microspheres significantly varied based on the plasticizer content in the formulation. DH release rate from EC-based matrix-type microspheres can be controlled by varying the DH to polymer and plasticizer ratios. Glass transition temperature values tended to decrease in conjunction with increasing amounts of TEC. Consequently, the various characteristics of the EC microspheres could be modified based on the plasticized ratio of TEC.

[Stone therapy-use and limitations of the guidelines]. / Steintherapie ­ Anwendung und Limitation medizinischer Leitlinien.

Increase of medical knowledge, technical innovation together with a demographic change, and increase of stone incidence in daily practice challenges guideline preparation and clinical studies. Increasing interdisciplinary collaboration in stone treatment can also be demonstrated in the number of affiliated professional and working groups in the current guideline update. The following case illustrates treatment options in a symptomatic patient harbouring bilateral stones and metabolic risk factors. Decision guidance for treatment and recurrence prevention measures are presented on the basis of expert opinion and available published evidence.

Three critical clinicobiological phases of the human SARS-associated coronavirus infections.

OBJECTIVE: COVID-19 immune syndrome is a multi-systemic disorder induced by the COVID-19 infection. Pathobiological transitions and clinical stages of the COVID-19 syndrome following the attack of SARS-CoV-2 on the human body have not been fully explored. The aim of this review is to outline the three critical prominent phase regarding the clinicogenomics course of the COVID-19 immune syndrome. MATERIALS AND METHODS: In the clinical setting, the COVID-19 process presents as "asymptomatic/pre-symptomatic phase", "respiratory phase with mild/moderate/severe symptoms" and "multi-systemic clinical syndrome with impaired/disproportionate and/or defective immunity". The corresponding three genomic phases include the "ACE2, ANPEP transcripts in the initial phase", "EGFR and IGF2R transcripts in the propagating phase" and the "immune system related critical gene involvements of the complicating phase". RESULTS: The separation of the phases is important since the genomic features of each phase are different from each other and these different mechanisms lead to distinct clinical multi-systemic features. Comprehensive genomic profiling with next generation sequencing may play an important role in defining and clarifying these three unique separate phases for COVID-19. From our point of view, it is important to understand these unique phases of the syndrome in order to approach a COVID-19 patient bedside. CONCLUSIONS: This three-phase approach may be useful for future studies which will focus on the clinical management and development of the vaccines and/or specific drugs targeting the COVID-19 processes. ANPEP gene pathway may have a potential for the vaccine development. Regarding the specific disease treatments, MAS agonists, TXA127, Angiotensin (1-7) and soluble ACE2 could have therapeutic potential for the COVID-19 course. Moreover, future CRISPR technology can be utilized for the genomic editing and future management of the clinical course of the syndrome.

The essentiality of vitamin D metabolites for embryonic chick development.

Laying hens maintained on 1,25-dihydroxyvitamin D3 as their sole source of vitamin D produce eggs which appear normal but which produce embryos having a defective upper mandible and which die at 18 to 19 days of embryonic life. Hens maintained on 25-hydroxyvitamin D3, on the other hand, produce normal embryos. Hens fed a vitamin D deficient diet produce eggs which develop the same embryonic defect. Injection of the affected eggs from the 1,25-dihydroxyvitamin D3 fed hens with vitamin D3, 25-hydroxyvitamin D3, or 1,25-dihydroxyvitamin D3 greatly increases the percentage of normal embryos. It therefore appears that 1,25-dihydroxyvitamin D3 is not transferred from hen to egg in sufficient amounts to support embryonic development and that vitamin D or its metabolites, or both, are necessary for normal chick embryo development.

Correlative study of lattice imperfections in long-range ordered, nano-scale domains in a Fe-Co-Mo alloy.

Recent advancements in data mining methods in atom probe microscopy have enabled new quantitative chemical and microstructural characterization beyond the standard three-dimensional reconstruction. For example, spatial distribution maps have been developed to enable visualisation of the local lattice occupation of a selected region of interest. However, the precision of such studies yet remains unknown as correlation with complementary methods would be required. Therefore, a correlative study of atom probe microscopy, neutron diffraction and microstructural modelling of long-range ordered, nano-scale domains in a well-researched Fe-Co-Mo Maraging-type steel is presented here. Its microstructure consists of Mo-enriched µ-phase (Fe,Co)7Mo6 particles embedded into a body-centred cubic FeCo matrix. Previous research has shown that under slow cooling conditions, this matrix partially decomposes into nano-scale B2 long-range ordered domains surrounded by disordered regions, resulting in reduced toughness in potential cutting applications. Usually, a long-range order parameter S referring to ideal B2 long-range order is assumed within such domains according to neutron diffraction. However, atom probe microscopy and modelling results presented in the current study indicate lattice imperfections with a partial substitution of atoms on the Fe- and Co-sublattices. After considering preferential retention effects during the atom probe experiment, a model unit cell is presented to define the observed imperfect B2 long-range order as pseudo-D03 long-range order, and the potential impact on the materials properties is discussed.

[Update of the 2Sk guidelines on the diagnostics, treatment and metaphylaxis of urolithiasis (AWMF register number 043-025) : What is new?] / Aktualisierung der S2k-Leitlinie zur Diagnostik, Therapie und Metaphylaxe der Urolithiasis (AWMF Registernummer 043-025) : Was ist neu?

The increase of medical knowledge and technical innovations together with the demographic change represent a challenge for the new conception of guidelines and clinical studies. The present S2k guidelines, which are exclusively concerned with kidney and ureteral stones, should support the treatment of urolithiasis in hospitals and private practices and provide information on urolithiasis for patients. Increasing interdisciplinary collaboration in stone treatment is also demonstrated in the number of professional and working groups participating in the update of the new guidelines. The present S2k guidelines emerged from a consensus process and demonstrate the current recommendations in step with actual practice. They provide decision-making guidance for diagnostics, treatment and metaphylactic measures based on expert opinions and available published fundamental evidence from the literature.

[New guidelines for urinary stone treatment. Controversy or development?]. / Neue Leitlinien zur Harnsteintherapie. Widerspruch oder Weiterentwicklung?

The new guidelines of the European (EAU), American (AUA), German, and Austrian associations of urology are based on thorough and consistent research and analysis of the published literature. However, the methodology is very diverse. In the case of the EAU-AUA guidelines on ureteral stones, the evidence was generated by a laborious meta-analysis of the entire available published literature on the subject. These guidelines represent the 1A level of evidence. The traditional European guidelines evaluate each statement separately and assign a level of evidence to each. The following aspects are new: the even greater effort to formulate guidelines accompanied by the initiation of international cooperative projects, clarity of presentation and evaluation of the individual statements (including levels of evidence), information on medication-based treatment to facilitate spontaneous passage of ureteral stones as well as stone fragments after extracorporeal shock wave lithotripsy (ESWL), a shift in the value of ESWL and ureterorenoscopy for ureteral stones, retrograde intrarenal surgery for small kidney stones refractory to ESWL or in settings unsuitable for ESWL, the use of laparoscopy in those rare cases that represent an indication for open surgery, and the additional value given to metaphylaxis in diagnosis and therapy. All of the new guidelines take these developments into account, although they differ slightly in the importance they assign to the individual items. The modifications represent the developments secondary to electronic data processing and preparation on the one hand and the rapid development of medical instruments on the other. Although ESWL is still the most important procedure for treating urinary stones, advances in flexible endoscopes, intracorporeal lithotripsy, and extraction instruments have led to a shift in the range of indications. These developments are fully accommodated in the new guidelines.

[Importance of open and laparoscopic stone surgery]. / Stellenwert der offenen und laparoskopischen Steinchirurgie.

INTRODUCTION: The increasing spread and technical enhancement of endourological methods has led to displacement of the surgical therapy of renal and ureteral calculi. MATERIALS AND METHODS: Based on a review of current literature, we describe indications, technique, and clinical importance of the open and laparoscopic management of urolithiasis. RESULTS: In Europe and North America, the surgical therapy of urolithiasis only plays a role in cases of very large or hard stones, after failure of shock wave lithotripsy, percutaneous nephrolithotripsy, or ureteroscopic stone removal, and in cases of abnormal renal anatomy, i.e., only in a few percent of all stone therapies. However, in developing countries and emerging markets with different structure and funding of the health care system where the methods of endourology are not readily available, these techniques still have a higher importance. Particularly in Europe, laparoscopic surgery is emerging because calculi can be removed from almost all locations in the kidney and ureter using a transperitoneal or retroperitoneal access. Functional outcomes and complication rates are comparable. The benefits of laparoscopy are less postoperative pain, shorter hospital stay, faster convalescence, and better cosmetic results. CONCLUSIONS: Although procedures for open and laparoscopic removal of renal and ureteral calculi are only performed in rare cases in daily urological practice, they are superior to the endourological techniques in some circumstances. Therefore, they should still be part of the urologist's skills.

Atom probe study of B2 order and A2 disorder of the FeCo matrix in an Fe-Co-Mo-alloy.

The physical and mechanical properties of intermetallic alloys can be tailored by controlling the degree of order of the solid solution by means of heat treatments. FeCo alloys with an appropriate composition exhibit an A2-disorder↔B2-order transition during continuous cooling from the disordered bcc region. The study of atomic order in intermetallic alloys by diffraction and its influence on the material properties is well established, however, investigating magnetic FeCo-based alloys by conventional methods such as X-ray diffraction is quite challenging. Thus, the imaging of ordered FeCo-nanostructures needs to be done with high resolution techniques. Transmission electron microscopy investigations of ordered FeCo domains are difficult, due to the chemical and physical similarity of Fe and Co atoms and the ferromagnetism of the samples. In this work it will be demonstrated, that the local atomic arrangement of ordered and disordered regions in an industrial Fe-Co-Mo alloy can be successfully imaged by atom probe measurements supported by field ion microscopy and transmission Kikuchi diffraction. Furthermore, a thorough atom probe parameter study will be presented and field evaporation artefacts as a function of crystallographic orientation in Fe-Co-samples will be discussed.

Novel Drug Delivery System for Dermal Uptake of Etofenamate: Semisolid SLN Dispersion.

BACKGROUND: Semisolid SLNs are novel strategy for dermal drug administration instead of incorporating the SLN dispersions into conventional semisolids. Etofenamate loaded semisolid SLNs were successfully prepared and in vitro characterization of formulations were performed in our previous study. The present study is an attempt to evaluate the dermal behavior of the semisolid SLNs selected on the basis of previous research and investigate the properties in terms of the convenience for topical applications. OBJECTIVE: The objective of this study is to evaluate the skin penetration characteristics of semisolid SLN formulations. The occlusive and mechanical properties of semisolid SLNs were also evaluated because of their impression on the dermal behavior of the formulations. METHOD: The occlusive properties were investigated by in vitro occlusion test. Texture analysis was performed to define the hardness, compressibility, adhesiveness, cohesiveness and elasticity of the formulations. Rat skin was chosen to evaluate the ex vivo penetration of etofenamate loaded semisolid SLNs and commercial gel product. Coumarin-6 was used to visualize the dermal distribution of the semisolid SLN formulations. For monitorizing the penetration of coumarin-6 into the skin samples Confocal Laser Scanning Microscopy was employed. RESULTS: The occlusive and mechanical properties of C1 coded semisolid SLN formulation were found more favorable in comparison with P1. The cumulative etofenamate amount in skin samples was found to be 39.88 ± 1.50 µg/cm2 for C1 and 30.56 ± 2.10 µg/cm2 for P1 coded formulations. According to CLSM images, greater fluorescence intensities and deeper skin penetrations were obtained with both of the semisolid SLNs in comparison to plain Carbopol gel. CONCLUSION: It can be concluded that the semisolid SLNs are promising alternative dermal drug delivery systems to the conventional dosage forms.

[Urolithiasis guidelines: retrospective view and perspectives]. / Steinleitlinie: Rück- und Ausblick.

The first German guidelines on urolithiasis were published in four sections in "Der Urologe A" in 1997 and were listed at The Association of the Scientific Medical Societies in Germany (AWMF) in 1999. The European Association of Urology (EAU) published the first guidelines on urolithiasis in 2000. All guidelines must be updated on a regular basis. Guidelines should represent the highest level of evidence for the best diagnostic and therapeutic procedures, independent of economic pressure. Guidelines should safeguard optimal patient care and also serve as a basis for education and training of healthcare professionals. They are a tool for quality management and for national healthcare structures and strategies as well as for the judicature. Medical guidelines form the foundation for the elaboration of local clinical treatment pathways, which are the bridge to treatment of patients and also take economic and regional circumstances into consideration. In the future information technology (IT) could play an even more important role for both the complex methods of establishing guidelines and their implementation. The contents of guidelines could then be directly integrated into the clinical pathway, if necessary or into electronic patient charts in order to propose a medically and financially optimized treatment pathway. Because of the complexity of producing guidelines, they will in part be produced at a national level and adapted to the regional circumstances. Future technical, medical and genetic developments will lead to a multidisciplinary and multiprofessional cooperation in the production of guidelines.

Intragenic dominant suppressors of glp-1, a gene essential for cell-signaling in Caenorhabditis elegans, support a role for cdc10/SWI6/ankyrin motifs in GLP-1 function.

The glp-1 gene product mediates cell-cell interactions required for cell fate specification during development in Caenorhabditis elegans. To identify genes that interact with glp-1, we screened for dominant suppressors of two temperature-sensitive glp-1 alleles and recovered 18 mutations that suppress both germline and embryonic glp-1 phenotypes. These dominant suppressors are tightly linked to glp-1 and do not bypass the requirement for a distal tip cell, which is thought to be the source of a signal that is received and transduced by the GLP-1 protein. Using single-strand conformation polymorphism (SSCP) analysis and DNA sequencing, we found that at least 17 suppressors are second-site intragenic revertants. The suppressors, like the original glp-1(ts) mutations, are all located in the cdc10/SWI6/ankyrin domain of GLP-1. cdc10/SWI6/ankyrin motifs have been shown to mediate specific protein-protein interactions in other polypeptides. We propose that the glp-1(ts) mutations disrupt contact between GLP-1 and an as yet unidentified target protein(s) and that the dominant suppressor mutations restore appropriate protein-protein interactions.

Biomechanical properties of Achilles tendon in diabetic vs. non-diabetic patients.

BACKGROUND/OBJECTIVES: Structural and functional impairments of the Achilles tendon in diabetic patients has the potential to contribute to ulcer formation through altered foot mechanics. This study aimed to examine the biomechanical and histopathological alterations in Achilles tendon specimens from diabetic vs. non-diabetic individuals. MATERIALS AND METHODS: 42 Achilles tendon samples obtained from patients treated with below-knee or above-knee amputation for chronic diabetic foot ulcers (n=21) or for non-diabetic conditions (n=21) were included. A tensile test was performed for each tendon and a stress vs. strain graft was obtained to calculate following biomechanical parameters: elasticity (Young modulus), load, stiffness, toughness, energy, strain, elongation and tenacity. Groups were also compared with regard to histopathological findings (inflammatory cell infiltration, collagen organization, and degeneration). RESULTS: Non-diabetic tendons exhibited a superior biomechanical profile over diabetic tendons with regard to the following biochemical parameters: elasticity, maximum load, stiffness, toughness, load, energy, strain and elongation at break point, tenacity, and strain at automatic load drop (p<0.05 for all comparisons). Diabetic tendons had mild impairment of collagen organization and focal collagen degeneration, whereas neither diabetic nor non-diabetic tendons had inflammatory cell infiltration. CONCLUSION: The structural and functional alterations associated with diabetes adversely affect the biomechanical properties of the Achilles tendon, potentially acting together with neuropathy and ischemia in the development of diabetic foot ulcers.

Development of etofenamate-loaded semisolid sln dispersions and evaluation of anti-inflammatory activity for topical application.

Dermal application of various active substances is widely preferred for topical or systemic delivery. SLNs consist of biocompatible and non-toxic lipids and have a great potential for topical application in drugs. In this study, semisolid SLN formulations were successfully prepared by a novel one-step production method as a topical delivery system of etofenamate, an anti-inflammatory drug. Compritol 888 ATO and Precirol ATO 5 were chosen as lipid materials for the fabrication of the formulations. In-vitro evaluation of the formulations was performed in terms of encapsulation efficiency, particle size, surface charge, thermal behavior, rheological characteristics, in vitro drug release profile, kinetics, mechanisms, stability, and anti-inflammatory activity. The colloidal size and spherical shape of the particles were proved. According to the results of the rheological analysis, it was demonstrated that the semisolid SLN formulations have a gel-like structure. Stability studies showed that semisolid SLNs were stable at 4°C for a six month period. Zero order release was obtained with Precirol ATO 5, while Compritol 888 ATO followed the square root of time (Higuchi's pattern) dependent release. Semisolid SLNs showed higher inhibitory activity of COX in comparison with pure etofenamate. In conclusion, etofenamate-loaded semisolid SLN formulations can be successfully prepared in a novel one-step production method and useful for topical application.

Bicyclic pyrazolines, potential central nervous system depressants and antiinflammatory agents.

The synthesis and CNS activity of a series of 34 substituted bicyclic pyrazolines are described. Ten of these compounds were also screened for antiinflammatory activity. One of the compounds (15) exhibited significant antiinflammatory activity in the carrageenan-induced edema test.

Angiotensin-converting enzyme inhibitors. Mercaptan, carboxyalkyl dipeptide, and phosphinic acid inhibitors incorporating 4-substituted prolines.

Analogues of captopril, enalaprilat, and the phosphinic acid [hydroxy(4-phenylbutyl)phosphinyl]acetyl]-L-proline incorporating 4-substituted proline derivatives have been synthesized and evaluated as inhibitors of angiotensin-converting enzyme (ACE) in vitro and in vivo. The 4-substituted prolines, incorporating alkyl, aryl, alkoxy, aryloxy, alkylthio, and arylthio substituents were prepared from derivatives of 4-hydroxy- and 4-ketoproline. In general, analogues of all three classes of inhibitors with hydrophobic substituents on proline were more potent in vitro than the corresponding unsubstituted proline compounds. 4-Substituted analogues of captopril showed greater potency and duration of action than the parent compound as inhibitors of the angiotensin I induced pressor response in normotensive rats. The S-benzoyl derivative of cis-4-(phenylthio)captopril, zofenopril, was found to be one of the most potent compounds of this class and is now being evaluated clinically as an antihypertensive agent. In the phosphinic acid series, the 4-ethylenethioketal and trans-4-cyclohexyl derivatives were found to be the most potent compounds in vitro and in vivo. A prodrug of the latter compound, fosinopril, is also being evaluated in clinical trials.

Substituted 1,2,3,4-tetrahydroaminonaphthols: antihypertensive agents, calcium channel blockers, and adrenergic receptor blockers with catecholamine-depleting effects.

Substituted 1,2,3,4-tetrahydroaminonaphthols were found to be calcium channel blockers with antihypertensive properties. These compounds also possessed adrenergic beta-receptor blocking activity. From the structure-activity studies, no clear correlation emerged between the in vitro calcium channel blocking activity and the acute anti-hypertensive activity in cannulated spontaneously hypertensive rats. Extensive pharmacological testing of selected compounds indicated that aminonaphthols are antihypertensive agents with many pharmacological properties. The relative contribution of various pharmacological actions toward the observed antihypertensive activity is unclear. Since the clinically useful calcium channel blocker verapamil is structurally related to these compounds, one of the aminonaphthols, trans-3-[(3,3-diphenylpropyl)amino]-1,2,3,4-tetrahydro-6,7 -dimethoxy-2-naphthalenol (12), was compared with verapamil for calcium channel blocking activity, adrenergic blocking activity, and catecholamine-depleting activity. Both compounds were found to be equipotent in these test systems.

Benzazepinone calcium channel blockers. 4. Structure-activity overview and intracellular binding site.

We have synthesized a series of benzazepinones (2) in order to determine the structure-activity relationships (SAR) for calcium channel blockers related to diltiazem. A prerequisite for calcium channel blocking activity in vitro and in vivo is the presence of two pharmacophores: a 4'-aryl methyl ether and a basic substituent appended to N1 with a pKa in the physiological range. When these constraints are satisfied, a wide variety of substitution is tolerated at C6, C7, and C3. The presence of an electron-withdrawing group at C6 appears to enhance potency in vitro and in vivo. For such benzazepinones, activity is primarily dependent upon lipophilicity, as measured by log P. We believe these compounds must partition into the cell membrane in order to access their receptor. The quaternary methiodide 15k was used to demonstrate that the binding site for benzazepinones is on the intracellular face of the membrane. This work represents the first comprehensive SAR of diltiazem-like calcium channel blockers.