Protocol for the treatment of cystoid macular edema secondary to retinitis pigmentosa and other inherited retinal dystrophies.

Inherited retinal dystrophies (IRD) are the leading cause of legal blindness in the working population. Cystic macular edema (CME) is one of the treatable causes of visual loss, affecting up to 50% of the patients. A bibliographic review has been carried out combining "inherited retinal dystrophy", "retinitis pigmentosa", "macular oedema" and a diagnostic-therapeutic protocol according to the levels of evidence and recommendations of the "US Agency for Healthcare Research and Quality". This protocol has been discussed in the monthly meetings of the XAREA DHR group with the participation of more than 25 ophthalmologists, creating a consensus document. The etiology of CME is multifactorial: dysfunction of the blood-retinal barrier, retinal pigment epithelium, and Müller cells, inflammation, and vitreous traction. OCT is the test of choice for the diagnosis and follow-up of CME associated with IRD. The drugs with the highest degree of scientific evidence are carbonic anhydrase inhibitors (IAC). Intravitreal corticosteroids, anti-VEGF, and vitrectomy with peeling of the internal limiting membrane do not have sufficient evidence. A treatment scheme is proposed for the CME in IRD in adults, another for pediatric patients and another for IRD and cataract surgery. Oral and topical IACs are effective in the treatment of CME secondary to IRD. Treatment with corticosteroids, anti-VEGF, and vitrectomy are second-line options. Randomized clinical trials are required to establish the therapeutic scale in these patients.

The expense of sending cerebrospinal fluid for analysis on all lumbar punctures in pediatric acute lymphoblastic leukemia patients.

BACKGROUND: Central nervous system (CNS) relapse in pediatric acute lymphoblastic leukemia (ALL) patients is uncommon. The cerebrospinal fluid (CSF) of patients with ALL is routinely sampled at each intrathecal chemotherapy treatment to screen for CNS relapse. The analysis of CSF is both time consuming and resource intensive and must be completed approximately 20 times per patient throughout treatment. Our objective was to examine the expense of routine screening on all CSF samples for CNS relapse in ALL patients, and to identify if CNS relapse can be detected clinically. METHODS: We identified all patients diagnosed with ALL at the Children's Hospital of Eastern Ontario (CHEO) between January 2001 and June 2021. We collected the total number of CSF samples in these patients and the number of CSF samples positive for CNS relapse. An in-depth chart review on the patients who relapsed in the CNS was completed to identify symptoms at relapse. RESULTS: Over the study period, 351 patients were diagnosed with ALL and underwent a total of 6515 lumbar punctures (LPs), each of which examined the CSF. The cost of CSF sample analysis is $14.32 (Canadian dollars [CDN]); thus, the total cost for the study sample was $93,294.80 (CDN). There were 14 CNS relapses and although symptoms including headache, vomiting, and fatigue were common, two patients were asymptomatic at relapse. CONCLUSIONS: Given the marginal cost of routine CSF screening and the lack of specific and sensitive symptoms for CNS relapse, we conclude that the routine practice of sending all CSF samples for analysis of CNS relapse in ALL patients is relatively inexpensive and beneficial.

Evaluation of Technical Competency in Healthcare Simulation (E-TeCHS) tool: a modified Delphi study.

Background: Graduates of simulation fellowship programmes are expected to have the ability to perform a variety of simulation specific skills at the time of graduation. Currently, simulation fellowship directors have access to tools to assess the ability of a fellow to debrief learners. However, there is no tool to assess a simulation fellow's competency in technical skills. The purpose of our manuscript was to develop and obtain content validation of a novel instrument designed to assess a simulation fellow's ability to perform the five core simulation technical skills. Methods: The study protocol was based on a methodology for content validation of curriculum consensus guidelines. This approach involves a three-step process, which includes the initial delineation of the curricular content. This was then followed by the validation of the curricular content using survey methodology and lastly obtaining consensus on modifications using Delphi methodology. Results: Two rounds of modified Delphi methodology were performed. Seventy-four respondents provided feedback on the round 1 survey and 45 respondents provided feedback on round 2. The final assessment tool has five elements and 16 subitems with four optional subitems. Conclusion: The Evaluation of Technical Competency in Healthcare Simulation tool provides an instrument developed from a national consensus of content experts. This tool provides simulation fellowship directors a method to evaluate fellows' competency in technical skills.

Introduction of Asian canine parvovirus in Europe through dog importation.

Canine parvovirus (CPV) is an important infectious agent of domestic and wild carnivores, responsible for severe and often fatal haemorrhagic gastroenteritis and leukopenia. This paper reports the genomic characterization of a CPV strain collected from a dog recently imported to Italy from Thailand. The virus was detected in all tissue samples collected. The whole genome encompassing the two open reading frames encoding for non-structural (NS1/NS2) and structural (VP1/VP2) proteins was amplified and sequenced. On the basis of genetic analysis of the VP2 gene, the isolate was characterized as CPV-2c, but it presented genetic signatures typical of Asian strains. Sequence analysis revealed the presence of amino acid changes never observed in European CPV-2c strains (NS1: Ile60Val, Tyr544Phe, Glu545Val, Leu630Pro; VP2: Ala5Gly, Phe267Tyr, Tyr324Ile, Gln370Arg). By phylogenetic analysis of full-length VP2 gene, the analysed strain clustered together with Asian viruses. Therefore, a possible introduction of the virus from Asia through the imported dog was suggested, thus confirming the important role of movement of dogs in the global spread of viruses. In addition, full-length genome analysis could help better trace the spread of canine viruses through different continents.

Effects of metformin versus placebo on vitamin B12 metabolism in non-diabetic breast cancer patients in CCTG MA.32.

BACKGROUND: Metformin is associated with low levels of vitamin B12 (VitB12) in patients with diabetes. The CCTG/MA.32 trial investigates the effects of metformin vs placebo on breast cancer (BC) outcomes in non-diabetic high-risk BC patients. We analyzed VitB12 at baseline and after 6 months of metformin (versus placebo) in the first 492 patients with paired blood samples. METHODS: VitB12 was analyzed centrally in baseline and 6-month fasting plasma. Levels <181 pmol/L were considered deficient, 181-221 pmol/L borderline, and ≥222 pmol/L sufficient. Methylmalonic acid (MMA) and homocysteine (HC) were assayed in those with VitB12 levels <222 pmol/L. Statistical analyses used Spearman's rank correlation coefficients and Wilcoxon signed-rank test for continuous variables and Chi-square test for categorical variables. RESULTS: 237 patients received metformin and 255 received placebo; median (inter quartile range) baseline VitB12 levels were 390 (290, 552) and 370 (290, 552) pmol/L in the metformin and placebo arms, respectively (p = 0.97). At 6 months, the median levels were 320 (244, 419) in the metformin versus 380 (286, 546) pmol/L in the placebo arm (p = 0.0001). At baseline, 15 patients (11 metformin and 4 placebo) had VitB12 <181 pmol/L, and at 6 months, 18 patients (15 metformin and 3 placebo) (p = 0.004). Median hemoglobin was similar at baseline, metformin, 130 g/L (124-137), and placebo arms, 131 g/L (124-137) (p = 0.38), and at 6 months, metformin, 131 g/L (91-162), and 131 g/L (106-169) in placebo group (p = 0.11). Of the 74 subjects with vitamin B12 <222 pmol/L at either time point (45 metformin, 29 placebo), at baseline MMA was normal in all patients and two had elevated HC (>15µmol/L). At 6 months, one patient (metformin) had MMA >0.4µmol/L and 3 (2 metformin, 1 placebo) had HC > 15µmol/L. CONCLUSIONS: There was an increased rate of biochemical VitB12 deficiency after 6 months of metformin; this was not associated with anemia. Further research will investigate VitB12 levels in all subjects at baseline and at 6 and 60 months.

Evidence for Tunisian-Like Pestiviruses Presence in Small Ruminants in Italy Since 2007.

The genus Pestivirus, which belongs to the Flaviviridae family, includes ssRNA+ viruses responsible for infectious diseases in pigs, cattle, sheep, goats and other domestic and wild ruminants. Like most of the RNA viruses, pestivirus has high genome variability with practical consequences on disease epidemiology, diagnosis and control. In addition to the officially recognized species in the genus Pestivirus, such as BVDV-1, BVDV-2, BDV and CSFV, other pestiviruses have been detected. Furthermore, most of the ruminant pestiviruses show low or absent species specificity observed in serological tests and are able to infect multiple species. Particularly, small ruminants are receptive hosts of the most heterogeneous group of pestiviruses. The aim of this study was to carry out the molecular characterization of pestiviruses isolated from sheep and goats in Sicily, Italy. Phylogenetic analysis of two viral genomic regions (a fragment of 5'-UTR and the whole Npro regions) revealed the presence of different pestivirus genotypes in the analysed goat and sheep herds. Two of five viral isolates were clustered with BVDV-1d viruses, a strain widespread in Italy, but never reported in Sicily. The other three isolates formed a distinct cluster with high similarity to Tunisian isolates, recently proposed as a new pestivirus species. This represents the first evidence for Tunisian-like pestivirus presence in small ruminants in Italy. Furthermore, one of the isolates was collected from a goat, representing the first isolation of Tunisian-like pestivirus from this species.

Stereospecific Oxidation of Diacetoxyheterobetulin with Ozone and Dimethyldioxirane.

Stereospecific oxidation of diacetoxyheterobetulin with ozone and dimethyldioxirane led to 3ß,28-diacetoxy-18α,19ßH-urs-20α,21α-epoxide with yields of 79% and 87%, respectively. Oxidation with ozone was not selective and gave two minor products containing 2lα-hydroxy-20(30)-ene and 21a-hydroxy-20ß,28-epoxy-fragments in ring E. The structures of 3ß,28-diacetoxy-18α,19ßH-urs-20α,21α-epoxide and 3ß-diacetoxy-21α-hydroxy-20ß,28-epoxy-18α,19ßH-ursane were confirmed by X-ray analysis for the first time.

Inhibition of Alpha-Glucosidase by Synthetic Derivatives of Lupane, Oleanane, Ursane and Dammarane Triterpenoids.

A variety of new and earlier synthesized lupane, oleanane, ursane and dammarane triterpenoids have been investigated for their inhibitory activity against α-glucosidase. 2,3-Indole-21 ß-acetyl-20ß,28-epoxy-18α,19ßH-ursane and 3-oxo-3A-homo-3a-aza-20(S)-hydroxydammar-24(25)-ene were synthesized for the first time. The compounds 3, 4, 8-11 and 14 demonstrated strong in vitro inhibitory activity towards α-glucosidase with IC50 values of 37.5-115.1 µM. 3-Deoxy-3a-homo-3a-aza-28-cinnamoyloxy-20(29)-lupene, with an IC50 of 6.67 µM was 60-fold more active than the market drug acarbose.

Síndrome piramidal y variaciones anatómicas como causa de dolor ciático insidioso / Pyrimidal syndrome and anatomical variations as a cause of insidious sciatic pain

Mujer de 42 años, que presentó durante 6 años clínica insidiosa de dolor e impotencia funcional de miembro inferior izquierdo con pruebas diagnósticas normales llegando a un diagnóstico de exclusión de origen funcional. Fue sometida a tratamientos y técnicas conservadores sin mejoría por lo que se decidió realizar cirugía exploratoria donde se observó una compresión del nervio ciático por una variación anatómica del músculo piriforme. Tras resecar parte del músculo piramidal y liberarse la rama del nervio ciático afectada, se constató mejoría del cuadro clínico quedando la paciente asintomática (AU)

The case is presented of a 42 year old woman who had been suffering a loss of strength in her left leg for six years. After an extensive diagnostic study, the pain was classified as of functional origin by a diagnosis of exclusion. Since then, the patient has tried all kind of drug treatments and conservative techniques without improvement. After an exhaustive study with inconclusive results, the case was discussed with the Orthopaedics Department, who performed an exploratory surgery, in which compression of the sciatic nerve due to an anatomical variation of the piriformis muscle was observed. Part of the muscle was resected during surgery and the sciatic nerve was freed, after which the patient experienced a great improvement (AU)

[Pyrimidal syndrome and anatomical variations as a cause of insidious sciatic pain]. / Síndrome piramidal y variaciones anatómicas como causa de dolor ciático insidioso.

The case is presented of a 42 year old woman who had been suffering a loss of strength in her left leg for six years. After an extensive diagnostic study, the pain was classified as of functional origin by a diagnosis of exclusion. Since then, the patient has tried all kind of drug treatments and conservative techniques without improvement. After an exhaustive study with inconclusive results, the case was discussed with the Orthopaedics Department, who performed an exploratory surgery, in which compression of the sciatic nerve due to an anatomical variation of the piriformis muscle was observed. Part of the muscle was resected during surgery and the sciatic nerve was freed, after which the patient experienced a great improvement.

A histological and functional study on hippocampal formation of normal and diabetic rats.

BACKGROUND: The hippocampus is a key brain area for many forms of learning and memory and is particularly sensitive to changes in glucose homeostasis. AIM OF THE WORK: To investigate in experimentally induced type 1 and 2 diabetes mellitus in rat model the effect of  diabetes mellitus on cognitive functions and related markers of hippocampal synaptic plasticity, and the possible impact of blocking N-methyl-D-aspartic acid (NMDA) receptors by memantine. MATERIALS AND METHODS: Seven rat groups were included: non-diabetic control and non-diabetic receiving memantine; type-1 diabetic groups - untreated, treated with insulin alone and treated with insulin and memantine; and type 2 diabetic groups - untreated and memantine treated. Cognitive functions were assessed by the Morris Water Maze and passive avoidance test. Biochemical analysis was done for serum glucose, serum insulin and insulin resistance. Routine histological examination was done, together with immunohistochemistry for detection of the hippocampal learning and memory plasticity marker, namely activity regulated cytoskeletal-associated protein (Arc), and the astrocytes reactivity marker, namely glial fibrillary acidic protein (GFAP).  RESULTS: Both type 1 and 2 untreated diabetic groups showed significantly impaired cognitive performance compared to the non-diabetic group. Treating the type 1 diabetic group with insulin alone significantly improved cognitive performance, but significantly decreased GFAP and Arc compared to the untreated type 1 group. In addition, the type 2 diabetic groups showed a significant decrease in hippocampus GFAP and Arc compared to the non-diabetic groups. Blocking NMDA receptors by memantine significantly increased cognitive performance, GFAP and Arc in the type 1 insulin-memantine group compared to the type 1-insulin group and significantly increased Arc in the type 2-memantine group compared to the untreated type 2 diabetic group. The non-diabetic group receiving memantine was, however, significantly adversely affected. CONCLUSION: Cognitive functions are impaired in both types of diabetes mellitus and can be improved by blockage of NMDA receptors which may spark a future therapeutic role for these receptors in diabetes-associated cognitive dysfunction.

Contornos y perfil de emergencia: aplicación clínica e importancia en la terapia restauradora / Contours and emergence profile: clinical application and importance in the restorative therapy

Una adecuada atención de los tejidos duros y blandos alrededor del diente y del implante antes, durante y después de los procedimientos restauradores incrementarán enormemente la probabilidad de un buen resultado. Los contornos coronales son determinados normalmente por la anatomía dentaria, la condición periodontal, la localización del margen gingival de la restauración y el acceso a la higiene bucal, sin dejar de considerar el compromiso estético subyacente. Los contornos de una restauración apropiada requieren una reducción adecuada del pilar que permita un espesor propicio de los materiales restauradores, mientras se permite a la vez un acceso fácil a la higiene dental. El perfil de emergencia de una restauración en un área estética presenta dos aspectos: la forma subgingival y la forma supragingival. La forma subgingival debe seguir los contornos de la unión cemento esmalte y el soporte de los tejidos gingivales. Considerando las limitaciones, el espesor aumentado de los contornos subgingivales interproximales conduce a un incremento en la altura de la papila, mientras que una ampliación de los contornos faciales favorece un posicionamiento apical de los tejidos gingivales. Estos y otros aspectos clínicos deben ser conocidos por el odontólogo cuando desea realizar una restauración con éxito (AU)

Close attention to both soft and hard tissues around teeth and implants before, during, and after restorative procedures will greatly increase the probability of a successful outcome. Crown contours are normally determined by tooth anatomy, periodontal condition, margin placement, and access for oral hygiene. However, compromises must occasionally be made in the interest of aesthetics. Proper restorative contours require adequate tooth reduction to allow proper thickness of restorative materials, while allowing easy access for personal oral hygiene. The emergence profile of a restoration in aesthetic areas has two aspects: subgingival form and supragingival form. The subgingival form should follow the contours of the cementoenamel junction and support the gingival tissues. Within limits, increased thickness of interproximal subgingival contours leads to increased papillary height, while increased facial contours lead to apical positioning of the gingival tissues. These and other clinical aspects must be known by the dentist when wishes to make a successful restoration (AU)

In situ continuous monitoring of chloride, nitrate and ammonium in a temporary stream Comparison with standard methods.

A multi-parameter probe was used for in situ chloride, nitrate and ammonium measurements in a temporary stream (Ribeira da Pardiela, in the South of Portugal). Comparison with standard analytical methods was performed for all elements. For chloride, the results of the probe depicted the same behaviour as that obtained with the standard method, although it is clear that the matrix effects were present. For nitrate, the results obtained with the probe were in agreement with the other standard methods used, except for samples collected during drought, when the stream water became brownish and exhaled an offensive smell, due to the decomposition of organic matter. For ammonium, surprisingly the probe show to be the best option, the phenate method being affected by matrix effects. The results still suggest an interference of the bicarbonate ion on nitrate determination, but standard additions approach was shown to minimize most of the matrix effects. Recoveries were reasonable to good for all the three anions under scrutiny.

Fracturas desplazadas de la espina tibial anterior. Valoración del tratamiento quirúrgico / Displaced fractures of the anterior tibial spine. Assessment of their surgical treatment

Objetivo. Analizar los resultados del tratamiento quirúrgico de las fracturas desplazadas de la espina tibial anterior y evaluar la reincorporación de estos pacientes a las actividades físicas previas. Material y método. Entre 1987 y 2003 fueron tratados quirúrgicamente 18 pacientes con fractura desplazada de espina tibial anterior de 19,9 años de edad; media (9-36). En dos pacientes se fracturaron ambas espinas tibiales. En 13 casos se realizó cirugía abierta y en 5 artroscópica. El método de fijación fue con tornillos en 13 casos, reinserciones transóseas en 3 y cerclajes alámbricos en 2 casos. La valoración clínica se realizó mediante la escala funcional de Lysholm y Gillquist, evaluando la reincorporación a las actividades deportivas mediante la escala de Tegner. Resultados. El seguimiento postquirúrgico medio fue de 36 meses (12-132). La puntuación media fue 94,7, con 14 resultados excelentes, 2 buenos y 2 regulares. Diecisiete pacientes (94%) no presentaron dolor y en dos casos (11%) se evidenció inestabilidad de rodilla. Dieciséis pacientes (88%) se reincorporaron al mismo nivel de actividad anterior a la lesión. Conclusiones. La fractura de la espina tibial anterior es una lesión con buen pronóstico, no suponiendo, en la mayoría de los casos, limitación significativa para las actividades físicas y deportivas, siendo la inestabilidad de rodilla la complicación más importante

Purpose. To analyze the results of the surgical treatment of displaced anterior tibial spine fractures and to assess the return of these patients to their former physical activities. Materials and methods. Between 1987 and 2003, 18 patients of a mean age of 19.9 (range: 9-23) underwent surgery for a displaced anterior tibial spine fracture. In two patients, both tibial spines were fractured. Open surgery was performed in 13 cases and arthroscopy in 5. Fixation was accomplished with screws in 13 cases, transosseous reattachments in 3 and cerclage wiring in 2 cases. The Lysholm-Gillquist score was used to carry out the patients' clinical assessment and return to sport activity was evaluated with the Tegner scale. Results. Mean postoperative follow-up was 36 months (range: 12-132). The average score was 94.7, with 14 excellent results, 2 good and 2 fair. Seventeen patients (94%) were pain free and in two cases (11%) knee instability was detected. Sixteen patients (88%) returned to the same level of activity as before the injury. Conclusions. Anterior tibial spine fractures are injuries with good prognosis and, in the majority of cases, do not lead to significant limitations on physical and sport activities. The most frequent complication is knee instability

The assimilatory nitrate reduction system of the phototrophic bacterium Rhodobacter capsulatus E1F1.

The phototrophic bacterium Rhodobacter capsulatus E1F1 assimilates nitrate under anaerobic phototrophic growth conditions. A 17 kb DNA region encoding the nitrate assimilation (nas) system of this bacterium has been cloned and sequenced. This region includes the genes coding for a putative ABC (ATP-binding cassette)-type nitrate transporter (nasFED) and the structural genes for the enzymes nitrate reductase (nasA), nitrite reductase (nasB) and hydroxylamine reductase (hcp). Three genes code for putative regulatory proteins: a nitrite-sensitive repressor (nsrR), a transcription antiterminator (nasT) and a nitrate sensor (nasS). Other genes probably involved in nitrate assimilation are also present in this region. The sequence analysis of these genes and the biochemical properties of the purified nitrate, nitrite and hydroxylamine reductases are reviewed.

Exploiting the vitamin B12 pathway to enhance oral drug delivery via polymeric micelles.

Vitamin B12 (VB12)-modified dextran-g-polyethyleneoxide cetyl ether (DEX-g-PEO-C16) was synthesized by linking VB12 residues to a DEX-g-PEO-C16 copolymer via a 2,2'-(ethylenedioxy)bis(ethylamine) spacer. The level of VB12 substitution on the DEX-g-PEO-C16 copolymer reached 1.68% (w/w). In aqueous solution, DEX-based copolymers form micelles that can entrap within their hydrophobic core up to 8.5% w/w of cyclosporin A (CsA), a poorly water soluble immunosuppressant. The permeability of Caco-2 cell membranes to CsA incorporated in VB12 modified and unmodified polymeric micelles was monitored in the presence and absence of intrinsic factor (IF). The apical (AP) to basolateral (BL) permeation of CsA through Caco-2 cell monolayers after 24 h of transport was significantly higher (1.8 and 2.3 times in absence and presence of IF, respectively) in the case of CsA loaded in VB12-modified polymeric micelles, compared to CsA in unmodified micelles. The results point to possible improvement in the application of polysaccharide-based polymeric micelles as targeted polymeric drug carriers for the oral delivery of poorly water soluble drugs.

Engineering polysaccharide-based polymeric micelles to enhance permeability of cyclosporin A across Caco-2 cells.

PURPOSE: To assess and compare the effectiveness of two types of polysaccharide-based micelles as delivery vehicles for poorly water soluble drugs by monitoring their permeability across Caco-2 cell monolayers. METHODS: Dextran (DEX) and hydroxypropylcellulose (HPC) were hydrophobically modified (HM) by grafting polyoxyethylene cetyl ether (POE-C16, 15 mol% and 5.4 mol%, respectively). The onset of micellization and mean diameter of polymeric micelles formed by HM-DEX and HM-HPC were determined by fluorescence spectroscopy and dynamic light scattering, respectively. Cyclosporin A (CsA)-loaded polymeric micelles were prepared by a dialysis procedure, and the amount of incorporated CsA was assayed by high performance liquid chromatography (HPLC). The stability of micelles in simulated gastric and intestinal fluids was studied as a function of contact time, and their cytotoxicity toward Caco-2 cells was evaluated using the MTT colorimetric assay. The bidirectional transport across Caco-2 cell monolayers of CsA entrapped in HM-DEX and HM-HPC micelles and of the polymers themselves was evaluated in the presence and absence of P-glycoprotein inhibitor. RESULTS: The amount of CsA incorporated in HM-HPC and HM-DEX micelles reached 5.5 and 8.5% w/w, respectively (entrapment efficiency of 22% or more). The polymeric micelles exhibited high stability in gastric and intestinal fluids and no significant cytotoxicity toward Caco-2 cells. The apical to basal permeability of CsA across Caco-2 cells increased significantly when loaded in polymeric micelles compared to free CsA. CONCLUSIONS: Polysaccharide-based polymeric micelles are promising carriers for the oral delivery of poorly water soluble drugs. In vitro tests indicate that, overall, HM-HPC micelles are more effective compared to HM-DEX micelles.

Solubilization of poorly water soluble drugs in micelles of hydrophobically modified hydroxypropylcellulose copolymers.

The main objective of this study is to exploit the solubilizing potential of hydroxypropylcellulose-g-polyoxyethylene alkyl ether (HPC-g-(POE)(y)-C(n)) polymeric micelles towards poorly water soluble drugs in order to improve their oral bioavailability. Hydrophobically modified HPC graft copolymers of various compositions were synthesized by attaching hexadecyl or octadecyl residues to the hydrophilic HPC backbone via short POE linkers of different lengths. The onset of micellization was estimated by fluorescence spectroscopy. The hydrodynamic diameter of different HPC-g-(POE)(y)-C(n) micelles was evaluated by dynamic light scattering (DLS). Cyclosporin A (CsA), a poorly water soluble immunosuppressant, was selected as model drug. CsA-loaded HPC-g-(POE)(y)-C(n) micelles were prepared by a dialysis procedure and the amount of CsA incorporated in the micelles was assayed by high-performance liquid chromatography. Following 24-h incubation with human colon adenocarcinoma, Caco-2 cells, the cytotoxicity of various HPC-g-(POE)(y)-C(n) copolymers was evaluated using the MTT colorimetric assay and compared to those of unmodified HPC and free (POE)(y)-C(n). In aqueous solution, different HPC-g-(POE)(y)-C(n) copolymers formed polymeric micelles of low critical association concentrations (CAC) and micelle mean diameters ranging from 78 to 90 nm. CsA loading into HPC-g-(POE)(y)-C(n) polymeric micelles was significantly larger than in unmodified HPC. It increased with increasing number of (POE)(y)-C(n) units grafted per HPC chain. On the cellular level, unmodified HPC showed no cytotoxicity, while free (POE)(y)-C(n) molecules inhibited cell growth. Most importantly, the study revealed that HPC-g-(POE)(y)-C(n) exhibited no significant cytotoxic effect.

Solubilization of cyclosporin A in dextran-g-polyethyleneglycolalkyl ether polymeric micelles.

Solubilization of the poorly water-soluble drug, Cyclosporin A (CsA), in aqueous dispersions of dextran-grafted-polyethyleneglycolalkyl ether (DEX-g-PEG-Cn) polymeric micelles was examined as a function of copolymer structure. In aqueous solution, DEX-g-PEG-Cn form polymeric micelles of low critical association concentrations (CAC) and small micelle sizes as determined by fluorescence spectroscopy and dynamic light scattering (DLS). Copolymers with longer polysaccharide chain showed larger CAC and mean diameter. The percentage of CsA loading into micelles was determined by high performance liquid chromatography. It was significantly larger in polymeric micelles compared to unmodified dextrans. It increased with increasing number of PEG-Cn units grafted per dextran chain and decreasing dextran molecular weight. The cytotoxicity of DEX-g-PEG-C(16) polymeric micelles towards Caco-2 cells, tested by MTT cytotoxicity assay, was significantly lower than that of free PEG-C(16) molecules. It can be concluded that the length of the hydrophilic part as well as the content and chemical nature of the hydrophobic substituents have an important effect on the ability of polymeric micelles to solubilize poorly-water soluble drugs.