Cyclosporin. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in immunoregulatory disorders

Total synthesis of cyclosporine: access to N-methylated peptides via isonitrile coupling reactions

Recent developments in the use of isonitriles to furnish secondary and tertiary amide bond formations have been applied to a novel total synthesis of the important cyclic polypeptide cyclosporine A. Specifically, the disclosed synthetic route demonstrates the utility of microwave-mediated carboxylic acid isonitrile couplings, thioacid isonitrile couplings at ambient temperature, and isonitrile-mediated couplings of carboxylic acids and thioacids with amines to form challenging amide bonds.

Nanoparticles made of multi-block copolymer of lactic acid and ethylene glycol containing periodic side-chain carboxyl groups for oral delivery of cyclosporine A

The purpose of this study was to evaluate the potential of new carboxylated multi-block copolymer of lactic acid and ethylene glycol (EL14) for nanoparticle (NP) formation and their ability to deliver high molecular weight hydrophobic drug--cyclosporine A (CsA). CsA-loaded EL14 NPs were compared with traditional poly(lactide-co-glycolide) (PLGA) NPs, both prepared by emulsion-diffusion-evaporation process. On the one hand, the increase in drug payload from 10 to 30 per cent for EL14 NPs showed no difference in particle size, however the entrapment efficiency tends to decrease from 50 to 43 per cent; on the other hand, the more hydrophobic PLGA showed an increasing trend in entrapment efficiency from 20 to 62 per cent with increasing particle size. Over 90 per cent of CsA was released in vitro from both the nanoparticulates; however, the release was much slower in the case of more hydrophobic PLGA. On in vivo evaluation in rats, the NPs made of EL14 showed a higher C(max), a faster T(max) and enhanced tissue levels to that of PLGA that are crucial for CsA's activity and toxicity; however, the overall bioavailability of the nanoparticulates was similar and higher than Neoral. Together these data demonstrate the feasibility of NPs made of low molecular weight, hydrophilic polymer EL14 for efficient delivery of CsA.

Chronic administration of cyclosporine A changes expression of BDNF and TrkB in rat hippocampus and midbrain

Neurotrophins, including the brain-derived neurotrophic factor (BDNF), are essential for regulating neuronal differentiation in developing brains. BDNF and its receptor tyrosine kinase receptor B (TrkB) are involved in neuronal signaling, survival and plasticity. Cyclosporine A (CsA) is a potent immunosuppressive agent which prevents allograft rejection in organ transplantation and various immunological diseases. We investigated whether chronic administration of CsA decreases BDNF gene expression in rats, and the influence of CsA on mRNA levels of TrkB receptors was also examined. For 30 days of CsA (10 mg/kg/day) administration, the expression of BDNF and TrkB mRNA was significantly decreased in the hippocampus and midbrain, but there was no significant difference in the cortex. CsA (0, 1, 5 10, 15 ug/ml) down-regulated BDNF and TrkB gene expression through cultured SH-SY5Y cells, as did all-trans retinoic acid (ATRA), and there was no effect on cell viability. These experimental results indicate that suppression of the BDNF and TrkB mRNA, protein level of BDNF expression in the hippocampus and midbrain may be related to altered behavior observed following chronic administration of CsA. A common mechanism of adverse effects of CsA induced depressive symptoms may involve neurotoxicity mediated by down-regulation of brain BDNF and TrkB.

Proteomic analysis in cyclosporin A-induced overgrowth of human gingival fibroblasts

Cyclosporin A (CsA) has been used as an immunosuppressive drug to prevent organ transplant rejection and to treat autoimmune diseases. CsA has a proliferative effect on human gingival fibroblasts (HGF) in vitro. However, the molecular mechanisms underlying CsA-induced proliferation in HGF remain to be elucidated. This study was aimed to investigate the CsA responsive proteins in HGF using systematic proteomic approach. Cell viability was determined by MTT assay and reactive oxygen species (ROS) was measured by fluorescent spectrometer. Proteins profiled by two-dimensional gel electrophoresis (2-DE) were identified by matrix-assisted laser desorption ionization time-of flight (MALDI-TOF) and electrospray ionization quadrupole time-of-flight mass spectrometry (EIQ-TOF MS). To confirm the expression changes of proteins by proteomics analysis, Western blot was performed using specific antibody. CsA increased the cell viability of HGF in a dose- and time-dependent manner. Significantly, seventeen proteins were overexpressed in the CsA-treated HGF, whereas three proteins were found to be expressed less than the untreated cells. The identified proteins were mainly related with cell proliferation, metabolism, and oxidation. The overexpression of peroxiredoxin 1 (Prx 1) confirmed by Western blotting and reduction of cytosolic reactive oxygen species (ROS) levels in the CsA-treated HGF demonstrated that Prx 1 may play a crucial role in the HGF proliferation induced by CsA. Upregulation of Galectin 3 in CsA-treated HGF indicated that it is related to CsA-induced proliferation. These proteomic analysis data will provide an efficient approach in understanding the mechanisms of HGF proliferation by CsA.

Preparation, characterization and in silico modeling of biodegradable nanoparticles containing cyclosporine A and coenzyme Q10

Combination therapy will soon become a reality, particularly for those patients requiring poly-therapy to treat co-existing disease states. This becomes all the more important with the increasing cost, time and complexity of the drug discovery process prompting one to look at new delivery systems to increase the efficacy, safety and patient compliance of existing drugs. Along this line, we attempted to design nano-scale systems for simultaneous encapsulation of cyclosporine A (CsA) and coenzyme Q10 (CoQ10) and model their encapsulation and release kinetics. The in vitro characterization of the co-encapsulated nanoparticles revealed that the surfactant nature, concentration, external phase volume, droplet size reduction method and drug loading concentration can all influence the overall performance of the nanoparticles. The semi-quantitative solubility study indicates the strong influence of CoQ10 on CsA entrapment which was thought to be due to an increase in the lipophilicity of the overall system. The in vitro dissolution profile indicates the influence of CoQ10 on CsA release (64%) to that of individual particles of CsA, where the release is faster and higher (86%) on 18th day. The attempts to model the encapsulation and release kinetics were successful, offering a possibility to use such models leading to high throughput screening of drugs and their nature, alone or in combination for a particular polymer, if chi-parameters are understood.

Cyclosporine a-loaded solid lipid nanoparticles: ocular tolerance and in vivo drug release in rabbit eyes

PURPOSE

To determine the in vivo efficacy of cyclosporine A-loaded solid lipid nanoparticles (SLNs) in rabbit eyes.

METHODS

SLNs were prepared and administered to the cul-de-sac of rabbits, and the drug amount in aqueous humor was detected by high performance liquid chromatography (HPLC). The irritation was evaluated by modified Draize testing.

RESULTS

The particle size of SLNs was detected as 225.9 +/- 5.5 nm with a negative surface charge. Aqueous humor drug levels reached 50.53 ng/mL, and there was no serious irritation in rabbit eyes.

CONCLUSIONS

Topical ophthalmic efficacy of cyclosporine A was enhanced via administration of SLNs.

Impact of polymeric nanoparticles on oral pharmacokinetics: a dose-dependent case study with estradiol

The present study reports the significance of polymeric nanoparticles in oral drug delivery from pharmacokinetic perspective. Impact of different dose polymeric nanoparticulate formulations on various pharmacokinetic parameters has been reported. All nano-formulations were found to have significant effect on important pharmacokinetic parameters like C(max), T(max), AUC, absolute bioavailability, absorption rate constant (K(a)), elimination rate constant (K(el)), elimination half life (t(1/2)), mean residence time (MRT) and mean absorption time (MAT). Further, drug in polymeric nanoparticles exhibited the flip-flop pharmacokinetics suggesting its slow and sustained release from the polymeric matrix. Together, polymeric nanoparticles hold promise for the oral delivery of molecules having pharmacokinetic hurdles in their delivery approach.

Alport syndrome: significance of gingival biopsy in the initial diagnosis and periodontal evaluation after renal transplantation

Alport Syndrome (AS) is an important hereditary disorder affecting the glomerular basement membrane. Diagnosis of AS is based on the presence of hematuric nephropathy, renal failure, hearing loss, ocular abnormalities and changes in the glomerular basement membrane of the lamina densa. The aims of this case report were to show the changes in the gingival tissues in a patient with AS under therapy with cyclosporin-A after renal transplantation and to discuss the possible role of type IV collagen in gingival basal lamina as an alternative approach for the diagnosis of AS. A 20-year-old male patient with AS underwent periodontal therapy including a series of gingivectomy surgeries. Gingival samples obtained during the second surgery were examined histopathologically and by transmission electron microscopy for further pathological examination. Gingivectomy procedures have been performed every 6 months over the last 4 years. The excessive and fibrous gingival enlargements resulted in migration of the anterior teeth, but no alveolar bone loss occurred. This is the first report to demonstrate the possible changes in the gingival tissues caused by AS. It is suggested that gingival biopsy can be an initial diagnostic tool instead of renal or skin biopsies. Proper dental and periodontal care and regular visits to the dentist could provide limited gingival hyperplasia to patients with AS.

Cyclosporine A reduces dendritic outgrowth of neuroblasts in the subgranular zone of the dentate gyrus in C57BL/6 mice

In the present study, we observed the effects of cyclosporine A (CsA), an efficient immunosuppressant, on cell proliferation and neuroblast differentiation in the subgranular zone of the dentate gyrus (SZDG) in normal C57BL/6 mice using Ki67 and doublecortin (DCX) immunohistochemical staining, respectively. At 8 weeks of age, vehicle (physiological saline) or CsA was daily administered (40 mg/kg, i.p.) for 1 week. Animals were sacrificed at 2 weeks after last administration. CsA treatment did not show any influences in neurons, astrocytes and microglia based on immunohistochemistry for its markers, respectively. However, in the CsA-treated group, Fluoro-Jade B, a marker for neurodegeneration, positive cells were found in the SZDG, not in the vehicle-treated group. In the vehicle-treated group, Ki67 immunoreactive (+) nuclei were clustered in the SZDG, whereas in the CsA-treated group Ki67(+) nuclei were scattered in the SZDG, showing no difference in cell numbers. Numbers of DCX(+) neuroblasts with well-developed processes (tertiary dendrites) were much lower in the CsA-treated group than those in the vehicle-treated group; however, numbers of DCX(+) neuroblasts with secondary dendrites were similar in both the groups. These results suggest that CsA significantly reduces dendritic outgrowth and complexity from neuroblasts in the SZDG without any affecting in neurons, astrocytes and microglia in normal mice.

Development of an automatic solid phase extraction and liquid chromatography mass spectrometry method by using a monolithic column for the analysis of Cyclosporin A in human plasma

A sensitive and specific and automated liquid chromatography-electrospray mass spectrometric (LC-ESI-MS) assay for the quantification of Cyclosporin A in human plasma was developed. Following a simple protein precipitation step, the supernatant was extracted on-line and directly injected into the system LC-ESI-MS. A relatively new type of monolithic column consisting of a silica rod with bimodal pore structure was used to achieve a retention time of 2.4 min with a very low backpressure at a flow rate of 1 ml/min. The assay was linear from 0.050 to 1.000 microg/ml. The mean recovery was 91%. The mean inter-day and intra-day precisions were 1.85% and 2.83%, respectively. The combination of the automated solid phase extraction and the low retention time achieved with this columns increase the throughput and decrease the time of analysis of each sample. This technology is useful in order to improve the efficiency of the bioanalytical studies.

Pediatric liver transplantation

In previous decades, pediatric liver transplantation has become a state-of-the-art operation with excellent success and limited mortality. Graft and patient survival have continued to improve as a result of improvements in medical, surgical and anesthetic management, organ availability, immunosuppression, and identification and treatment of postoperative complications. The utilization of split-liver grafts and living-related donors has provided more organs for pediatric patients. Newer immunosuppression regimens, including induction therapy, have had a significant impact on graft and patient survival. Future developments of pediatric liver transplantation will deal with long-term follow-up, with prevention of immunosuppression-related complications and promotion of as normal growth as possible. This review describes the state-of-the-art in pediatric liver transplantation.

Cyclosporins from Mycelium sterilae MS 2929

The structures of two new cyclosporins were elucidated by NMR and MS methods as cyclo[-MeBmt(1)-Abu(2)-Sar(3)-MeLeu(4)-Val(5)-MeLeu(6)-Ala(7)-d-Ala(8)-MeLeu(9)-MeNva(10)-MeVal(11)-] and cyclo[-MeBmt(1)-Abu(2)-Sar(3)-MeLeu(4)-Abu(5)-MeLeu(6)-Ala(7)-d-Ala(8)-MeLeu(9)-MeLeu(10)-MeVal(11)-].

Gene expression, cytoskeletal changes and extracellular matrix synthesis in human osteoblasts treated with cyclosporin A

Cyclosporin A (CyA) is an immunosuppressive agent used to prevent allograft rejection, but unfortunately it causes adverse effects such as bone diseases, osteoporosis and osteomalacia. These pathologies involve an imbalance between synthesis, degradation and mineralization of extracellular matrix. CyA can modify extracellular matrix components such as glycosaminoglycans (GAG) and collagen fibers. In addition, normal cell activity is dependent on cell morphology and substrate cell attachment. We treated normal human osteoblasts with CyA and analyzed: (i) gene expression by a microarray method; (ii) extracellular GAG and collagen after (3)H-glucosamine and Western blot analysis; and (iii) cytoskeletal changes, using actin and tubulin fluorescent antibodies. CyA increased intra- and extracellular GAG and extracellular GAG classes such as hyaluronic acid, chondroitin sulphate, and dermatan sulphate; there was no noteworthy effect on heparan sulphate and the ratio of non-sulphated to sulphated GAG. In osteoblast cultures the drug reduced cytoskeletal actin, while tubulin did not change. In vivo the osteoblasts showed morphological changes with different extracellular matrix synthesis. Microarray analysis indicated the inhibition of gene pathways related to Wnt signaling molecules, and the cytoskeletal and focal adhesion cascade. In in vitro human osteoblasts CyA modified gene expression related to cytoskeletal pattern organization and cell morphology. Since in bone pathologies osteoblasts show different morphology related to cell size, these data suggest that in vivo osteoblast different functions could be dependent on alteration of osteoblast differentiation.

Prolonged ocular hypotension: would ciliary tissue transplantation help

AIMS

Ocular hypotony and phthisis bulbi from persistent fistulae, ciliochoridal detachments, or inflammation, that cannot be treated currently. However, complete shutdown of the ciliary epithelium is rare. Secreting, transplanted ciliary tissue could restore the IOP to a level where further visual damage would not occur or even be reversed.

METHODS

Allografts of ciliary epithelium and its substrate were placed on to the surface of the iris of normal albino rabbits. The progress of the transplanted tissue was followed in the untreated animals, those who had been immunosuppressed and those who had been immunosuppresed together with cold whole body perfusion for up to 55 days. Changes were assessed by slit-lamp observation, luconyl blue staining, fluoresceine angiography, and these were compared with the histology and electron microscopic appearances.

RESULTS

Transplants survived the period of ischaemia in the anterior chamber. They started to be revascularised within 4 days and were completely revascularised in 12 days. Untreated animals showed classical rejection phenomena. However, the ciliary epithelial tissue in those animals who were immunosuppressed and had been subjected to whole body perfusion remained normal and were secreting aqueous, as judged by the histological and electron microscopic appearances.

CONCLUSIONS

Perfused allografts of ciliary tissue will survive in the normal anterior chamber of the immunosuppressed rabbit, and the electron microscopic evidence indicates that the tissue is producing aqueous. If this can be shown to be adequate in the damaged eye, then ciliary transplantation could be a valuable tool in the management of severe intractable hypotony.

Inhibition of apoptotic signals in overgrowth of human gingival fibroblasts by cyclosporin A treatment

Cyclosporin A (CsA), an immunosuppressive drug, has overgrowth effects on human gingival fibroblasts (HGF) in vitro. However, the molecular mechanism responsible for the CsA-induced gingival overgrowth remains still unclear. The present study is aimed to investigate the correlation with the apoptotic signal pathway in CsA-induced overgrowth of HGF. CsA-treated HGF were assessed for cell viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, for reactive oxygen species (ROS) detection by flow cytometry, for proliferation ability using the 5-bromo-20-deoxyuridine (BrdU), for caspase activities biochemically, for expression of apoptotic signal molecules such as cytochrome c, Fas and Fas-L and Bcl-2 family by Western blotting and VDAC by RT-PCR. CsA increased the cell viability, but not the number of BrdU-positive HGF, indicating that CsA fails to induce the proliferation of HGF. CsA also decreased the intracellular reactive oxygen species level in HGF. This was accompanied by that the antiapoptotic protein Bcl-2 was upregulated whereas the proapoptotic protein Bax was downregulated. Moreover, CsA downregulated VDAC, a mitochondrial transition pore, and decreased the level of cytochrome c released from the mitochondria into the cytosol and activation of caspase-3 and -9 associated with mitochondria-mediated apoptosis. On the other hand, Fas-L level and caspase-8 activation, the major mediator of the death receptor-mediated apoptosis, were diminished in the CsA-treated HGF. CsA inhibits the apoptotic signal molecules such as cytochrome c, caspases and Fas-L with the regulation of Bcl-2 family whereas it has no effect on cell division, which can contribute to overgrowth of HGF. These findings suggest that the decreased apoptosis plays a more important role than the increased cell proliferation in the CsA-induced overgrowth of HGF.

Gingival crevicular fluid transforming growth factor-beta1 in cyclosporine and tacrolimus treated renal transplant patients without gingival overgrowth

BACKGROUND

Gingival crevicular fluid (GCF) levels of transforming growth factor-beta(1) (TGF-beta(1)) have been previously investigated in relation to the pathogenesis of cyclosporine-A (CsA)-induced gingival overgrowth (GO) but no clinical data are available regarding the GCF levels of TGF-beta(1) in patients treated with tacrolimus (Tac). However, as gingival inflammation is pronounced at sites of GO and this consequently may lead to an elevation in TGF-beta(1) levels the present study aimed to evaluate gingival crevicular fluid (GCF) TGF-beta(1) levels in renal transplant patients using CsA or Tac without GO.

METHODS

GCF TGF-beta(1) levels were investigated in 30 renal transplant patients without GO medicated with either CsA (n=15) or Tac (n=15). Sixteen gingivitis patients and 15 periodontally healthy subjects were selected as controls. Periodontal status was evaluated by measuring probing depth, plaque index and papilla bleeding index. The TGF-beta(1) levels were analysed by enzyme-linked immunosorbent assay.

RESULTS

Both CsA and Tac groups had significantly elevated GCF TGF-beta(1) total amount compared to gingivitis and healthy groups (p<0.008). GCF TGF-beta(1) total amount of CsA and Tac groups was similar (p>0.008). Gingivitis and healthy groups had also similar GCF TGF-beta(1) total amount (p>0.008).

CONCLUSIONS

Within the limits of the present data it is unlikely that TGF-beta(1) is an exclusive mediator of CsA- or Tac-induced GO. However, pathogenesis of GO is multifactorial and contribution of TGF-beta(1) to the interrelations between cytokines and growth factors with fibrogenic potential cannot be disregarded.

Peristomal dermatology

Inflammatory or infectious conditions affecting the skin around an intestinal stoma are common and may be a source of considerable aggravation to patients. Recognition and prompt appropriate treatment of these conditions improves their quality of life. Peristomal pyoderma gangrenosum represents a most unusual peristomal skin condition that is difficult to treat; resolution often requires diagnosis and therapy of underlying inflammatory bowel disease.

Alendronate therapy in cyclosporine-induced alveolar bone loss in rats

BACKGROUND AND OBJECTIVE

Cyclosporine A is an immunosuppressive drug that is widely used in organ transplant patients as well as to treat a number of autoimmune conditions. Bone loss is reported as a significant side-effect of cyclosporine A use because this can result in serious morbidity of the patients. As we have shown that cyclosporine A-associated bone loss can also affect the alveolar bone, the purpose of this study was to evaluate the effect of the concomitant administration of alendronate on alveolar bone loss in a rat model.

MATERIAL AND METHODS

Forty Wistar rats (10 per group) were given cyclosporine A (10 mg/kg, daily), alendronate (0.3 mg/kg, weekly), or both cyclosporine A and alendronate, for 60 d. The control group received daily injections of sterile saline. The expression of proteins associated with bone turnover, including osteocalcin, alkaline phosphatase and tartrate-resistant acid phosphatase (TRAP), and also the calcium levels, were evaluated in the serum. Analysis of the bone volume, alveolar bone surface, the number of osteoblasts per bone surface and the number of osteoclasts per bone surface around the lower first molars was also performed.

RESULTS

The results indicate that cyclosporine A treatment was associated with bone resorption, represented by a decrease in the bone volume, alveolar bone surface and the number of osteoblasts per bone surface and by an increase in the number of osteoclasts per bone surface and TRAP-5b. These effects were effectively counteracted by concomitant alendronate administration.

CONCLUSION

It is concluded that concomitant administration of alendronate can prevent cyclosporine A-associated alveolar bone loss.

Advanced delivery of ciclosporin A: present state and perspective

Ciclosporin A has been used as an immunosuppressor for organ transplantation and other autoimmune disorders for a number of years. Its poor biopharmaceutical characteristics of low solubility and permeability makes the uphill task of designing delivery systems even more challenging for the drug delivery scientist. Works have been performed to investigate administration through various body routes, and have employed approaches that use as emulsions, microspheres, nanoparticles, liposomes, physical and chemical penetration enhancers. Although progress has been made, there is still room for improvement in the application of ciclosporin A, as none of these formulations is ideal.

Calcineurin inhibitors in pediatric renal transplant recipients

The calcineurin inhibitors, cyclosporine (ciclosporin) [microemulsion] and tacrolimus, are the principal immunosuppressants prescribed for adult and pediatric renal transplantation. For pediatric patients, both drugs should be dosed per body surface area, and pharmacokinetic monitoring is mandatory. While monitoring of the trough levels may suffice for tacrolimus, cyclosporine therapy that utilizes the microemulsion formulation requires additional monitoring (e.g. determination of 2-hour post-dose levels). In a well designed randomized study in children, as in studies in adults, there was no difference in short-term patient and graft survival with cyclosporine microemulsion and tacrolimus. However, tacrolimus was significantly more effective than cyclosporine microemulsion in preventing acute rejection after renal transplantation when used in conjunction with azathioprine and corticosteroids. With regard to long-term outcome, the difference in acute rejection episodes resulted in a better glomerular filtration rate at 1 year after transplantation and eventually in better graft survival 4 years after renal transplantation. Whether this difference persists when calcineurin inhibitors are used in combination with mycophenolate mofetil has not been determined. The prevalence of hypomagnesemia was higher in the tacrolimus group whereas hypertrichosis and gingival hyperplasia occurred more frequently in the cyclosporine group. In contrast with adults, the incidence of post-transplantation diabetes mellitus was not significantly different between tacrolimus- and cyclosporine-treated patients. There was also no difference with regard to post-transplantation lymphoproliferative disorder. Medication costs were similar, but in view of the lower rejection episodes and better long-term graft survival as well as the more favorable cosmetic side effect profile, tacrolimus may be preferable. The recommendation drawn from the available data is that both cyclosporine and tacrolimus can be used safely and effectively in children. We recommend that cyclosporine should be chosen when patients experience tacrolimus-related adverse events.

Cyclosporin in the treatment of patients with atopic eczema - a systematic review and meta-analysis

OBJECTIVE

To systematically assess the effectiveness of systemic cyclosporin in patients with severe atopic eczema.

STUDY DESIGN

Systematic review and meta-analysis of controlled and uncontrolled trials. Electronic (MEDLINE, Cochrane databases) and hand search of published work. Independent standardized assessment of eligibility and data abstraction by two reviewers.

METHODS

For the qualitative review data on study design, study population, methodology, results, tolerability and methodological quality was independently extracted by two reviewers. Qualitatively homogeneous studies were pooled using a random-effects model. The mean relative change in objective disease severity was chosen as the main outcome measure for the quantitative analysis. Publication bias was explored by regressing treatment effect on sample size. Sensitivity analysis included meta-regression of study-specific covariates (inclusion of children, study type, concomitant topical therapy, study quality).

RESULTS

Fifteen studies including 602 patients met the eligibility criteria. In all studies analysed, cyclosporin consistently decreased the severity of atopic eczema. Twelve studies appeared homogeneous enough to be pooled. After 2 weeks of treatment we found a dose-related response with a pooled mean decrease in disease severity of 22% (95%-CI 8-36%) under low-dose cyclosporin ( 3 mg/kg) and 40% (95%-CI 29-51%) at dosages >or=4 mg/kg. After 6-8 weeks the relative effectiveness was 55% (95%-CI 48-62%).

CONCLUSIONS

Due to evidence of publication bias the quantitative results need to be interpreted with caution. Effectiveness of cyclosporin is similar in adults and children, but tolerability might be better in children. As data to adequately evaluate the long-term effectiveness and safety of cyclosporin in patients with atopic eczema are unavailable, long-term registries are encouraged.

Expression of fibronectin-binding integrins in gingival epithelium in drug-induced gingival overgrowth

BACKGROUND AND OBJECTIVE

Gingival overgrowth is a side-effect of nifedipine and cyclosporin medications. Integrins are transmembrane glycoproteins that mediate cell adhesion, regulate cell proliferation and participate in the regulation of tissue fibrosis. The aim of this study was to investigate whether expression of epithelial cell integrins is linked to the development of drug-induced gingival overgrowth.

MATERIAL AND METHODS

Human gingival biopsies of patients taking nifedipine, cyclosporin, or a combination of both medications, were used. Expression of the alpha5beta1, alphavbeta1 and alphavbeta6 integrins, and of cellular extra domain A of fibronectin, was localized in frozen sections using immunohistochemistry.

RESULTS

The activated conformation of the beta1, alpha5beta1 and alphavbeta6 integrins were more frequently expressed in distinct locations in the oral epithelium in the combined drug group. Cellular extra domain A of fibronectin, a ligand for both alpha5beta1 and alphavbeta6 integrins, was expressed within the connective tissue of all groups. It was also expressed around the basal keratinocytes of the control, nifedipine and cyclosporin-induced gingival overgrowth groups, but not in the combined medication group. No relationship between the presence of inflammation and integrin expression was found.

CONCLUSION

The results indicate that expression of certain integrins is up-regulated in the epithelium of drug-induced gingival overgrowth where they could participate in controlling the formation of elongated rete ridges and tissue fibrosis.

Cyclosporine A inhibits acetylcholinesterase activity in rats experimentally demyelinated with ethidium bromide

Cyclosporine A is the major immunosuppressive agent used for organ transplantation and for the treatment of a variety of autoimmune disorders such as multiple sclerosis. In this work, we investigated the effect of the cyclosporine A on the acetylcholinesterase activity in the cerebral cortex, striatum, hippocampus, hypothalamus, cerebellum and pons of the rats experimentally demyelinated by ethidium bromide. Rats were divided into four groups: I control (injected with saline), II (treated with cyclosporine A), III (injected with 0.1% ethidium bromide) and IV (injected with 0.1% the ethidium bromide and treated with cyclosporine A). The results showed a significant inhibition (p<0.05) of acetylcholinesterase activity in the groups II, III and IV in all brain structures analyzed. In the striatum, hippocampus, hypothalamus and pons the inhibition was greater (p<0.005) when ethidium bromide was associated with cyclosporine A. In conclusion, the present investigation demonstrated that cyclosporine A is an inhibitor of acetylcholinesterase activity and this effect is increased after an event of toxic demyelination of the central nervous system.

PLGA nanoparticles for oral delivery of cyclosporine: nephrotoxicity and pharmacokinetic studies in comparison to Sandimmune Neoral

The cyclosporine-loaded poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) were prepared by the emulsion-diffusion-evaporation method and were optimized for particle size and entrapment efficiency. The optimized particles were 143.3+/-8.7 nm in size with narrow size distribution and 71.9+/-1.7% entrapment efficiency at 20% w/w initial drug loading when prepared with 0.1% w/v of Didodecylmethylammonium bromide (DMAB) as stabilizer. These particulate carriers exhibited controlled in vitro release of cyclosporine for 23 days at a nearly constant rate and showed very good hemocompatibility in vitro. The nanoparticulate formulation showed significantly higher intestinal uptake as compared to Sandimmune Neoral and cyclosporine suspension. The relative bioavailability of nanoparticulate formulation was found to be 119.2% as compared to Sandimmune Neoral. A marked difference in the pharmacokinetic profile between nanoparticulate and Sandimmune Neoral formulations was observed where nanoparticulate formulation showed controlled release of cyclosporine over 5 days, on the other hand, the marketed formulation showed a sharp Cmax with a 3-day release profile. The nanoparticulate formulation exerted significantly lower nephrotoxicity in the rats as compared to Sandimmune Neoral, which was evidenced by lower blood urea nitrogen (BUN), plasma creatinine (PC) and malondialdehyde (MDA) levels in plasma and kidney. The results were further supported by the histopathological changes in kidneys. Together, these results indicate that PLGA NPs have greater potential for oral delivery of cyclosporine.

Caspase-dependent apoptosis induced by calcineurin inhibitors was prevented by glycogen synthase kinase-3 inhibitors in cultured rat cortical cells

Calcineurin is selectively enriched within neurons of the central nervous system. The mechanism of calcineurin inhibitor-induced neurotoxicity remains poorly understood. The purpose of this study is to examine whether glycogen synthase-3 (GSK-3) is involved in calcineurin inhibitor-induced apoptosis. Calcineurin inhibitors such as cyclosporine A (CsA) and FK506 increased apoptotic cell death with morphological changes characterized by cell shrinkage, nuclear condensation of fragmentation, and internucleosomal DNA fragmentation. Alsteropaullone and 1-azakenpaullone, GSK-3 inhibitors, prevented calcineurin inhibitor-induced apoptosis. In addition, insulin growth factor-I (IGF-I) and cycloheximide completely blocked cell death. Moreover, caspase-3 activation was accompanied by calcineurin inhibitor-induced cell death. These results suggest that calcineurin inhibitors induce caspase-dependent apoptosis and activation of GSK-3 is involved in cell death in rat cortical neurons.

The up-regulation of type I plasminogen activator inhibitor in human gingival fibroblasts stimulated with cyclosporin A

BACKGROUND AND OBJECTIVE

Cyclosporin A is used as an immunosuppressive agent and its prominent side-effect is the induction of fibrous gingival overgrowth. The progression of fibrous gingival overgrowth results from the accumulation of extracellular matrix. Type I plasminogen activator inhibitor (PAI-1) acts as the inhibitor of extracellular matrix degradation and is involved in some fibrotic diseases. However, little is known about the correlation between PAI-1 and cyclosporin A-induced gingival overgrowth. The aim of this study was to investigate the effects of cyclosporin A on the expression of PAI-1 mRNA and protein in human gingival fibroblasts human gingival fibroblasts in vitro and to compare PAI-1 expression in normal healthy gingival tissues and cyclosporin A-induced gingival overgrowth specimens in vivo.

MATERIAL AND METHODS

Quantitative reverse transcription-polymerase chain reaction and western blot assay were used to investigate the effects on human gingival fibroblasts exposed to cyclosporin A. In addition, 10 cyclosporin A-induced gingival overgrowth specimens and five normal gingival tissues were examined by immunohistochemistry.

RESULTS

Investigations of the time dependence of PAI-1 mRNA expression in human gingival fibroblasts treated with 200 ng/ml of cyclosporin A revealed a rapid accumulation of the transcript: a significant signal was first detectable after 1 h of exposure and the signal remained elevated throughout the 24-h incubation period (p < 0.05). Cyclosporin A was also found to up-regulate PAI-1 protein in a time-dependent manner (p < 0.05). The PAI-1 staining in gingival tissue was stronger in the cyclosporin A-induced gingival overgrowth group than in the normal gingival group (p < 0.05). In the cyclosporin A-induced gingival overgrowth group, intensive staining for PAI-1 expression was observed mainly in the cytoplasm of fibroblasts, endothelial cells and inflammatory cells.

CONCLUSION

These findings suggest that the up-regulation of PAI-1 may play an important part in the molecular pathogenesis of cyclosporin A-induced gingival overgrowth.

Influence of cyclosporin A on quality of bone around integrated dental implants: a radiographic study in rabbits

OBJECTIVES

To evaluate the influence of cyclosporin A (CsA) administration on bone around integrated dental implants assessed by a bone quality index and by quantitative subtraction radiography.

MATERIAL AND METHODS

A total of 36 machine surface commercial implants were placed in 18 adult rabbits. After a 3-month healing period without any disturbance, the animals were randomly divided into three groups of six animals each. Group A was sacrificed at this time. CsA was injected subcutaneously in an immunosuppressive dose of 10 mg/kg/day in a test group (Group T), and a Group B served as a control, receiving only vehicle. After 3 months of cyclosporin administration, the animals of both Groups B and T were sacrificed. Radiographs were obtained at implant surgery and at the day of sacrifice with a CMOS sensor. Bone quality around the implants was compared between the groups using a bone quality index and quantitative subtraction radiography.

RESULTS

The bone analysis showed that in Group T, the bone quality changed dramatically from a dense cortical to a loose trabecular bone structure (P<0.0001, chi(2) test) while in Groups A and B there were no significant differences. Quantitative digital subtraction radiography showed significantly (P<0.05) lower gray shade values (radiographic density) in a region of bone formation around the implants in Group T (118+/-12) than in Groups A (161+/-6) and B (186+/-10).

CONCLUSION

Within the limits of this study, CsA administration has a negative effect on the quality of bone around integrated dental implant.

Disease, destination, dose and delivery aspects of ciclosporin: the state of the art

Since its discovery in 1971, ciclosporin has revolutionized organ transplantation and the treatment of autoimmune disorders. The wide array of applications resulting from its clinical efficacy warrant unique administration strategies and varying doses, times of exposure and extents of distribution, depending on target tissue. The poor biopharmaceutical characteristics of low solubility and permeability makes this uphill task even more challenging for the drug delivery scientist. Efforts underway have explored various body routes employing approaches like emulsions, microspheres, nanoparticles, liposomes, iontophoresis and penetration enhancers. This review attempts a brief holistic view of the "four Ds" (disease, destination, dose and delivery) surrounding this immunomodulator drug.

Topical 2% cyclosporine A in preservative-free artificial tears for the treatment of vernal keratoconjunctivitis

BACKGROUND

A double-masked, placebo-controlled trial to evaluate the short-term efficacy and safety of topical 2% cyclosporine A in preservative-free artificial tears for patients with vernal keratoconjunctivitis.

METHODS

Twenty patients with severe vernal keratoconjunctivitis were included in the study. All were treated with topical 2% cyclosporine A eye drops. One eye of each patient was administered 2% cyclosporine A in preservative-free artificial tears; the fellow eye received the placebo (vehicle) for the first 2 weeks, in a double-masked, placebo-controlled trial. Thereafter, the placebo eye received cyclosporine A (open trial). Symptoms and signs were scored on the day of enrollment and at the end of week 2, 4, and 14.

RESULTS

At the end of week 2, no statistically significant decrease was noted from baseline in mean scores of either signs (p = 0.18) or symptoms (p = 0.50) in the eyes that received placebo. On the other hand, a statistically significant decrease was observed in both sign and symptom scores (p < 0.001, for both) of eyes that received cyclosporine A. Significant differences were also noted at 2 weeks in mean scores of both signs and symptoms (p < 0.001, for both) between the eyes that received cyclosporine A and those that received placebo. At week 4 and 14, statistically significant decreases in both sign scores and symptom scores were noted compared with baseline in the eyes that received cyclosporine A and in the eyes that had initially received placebo (p < 0.001, for all).

INTERPRETATION

Topical 2% cyclosporine A in preservative-free artificial tears is effective in alleviating signs and symptoms of patients with severe vernal keratoconjunctivitis and had no observed side effects over the course of the study.

Drug-drug interaction after single oral doses of the furanocoumarin methoxsalen and cyclosporine

Furanocoumarins increase the bioavailability of drugs that are CYP3A4 substrates. A possible interaction of methoxsalen with cyclosporine was evaluated in 12 healthy volunteers following oral administration of 40 mg methoxsalen, 200 mg cyclosporine, or a combination of both in a randomized crossover study. Methoxsalen increased area under the plasma concentration-time curve (AUC) and peak plasma concentration (Cmax) of cyclosporine by 29% (range, -20% to 172%; P < .05) and 8% (range, -10% to 26%; P < .05), respectively, compared to cyclosporine alone. The AUC geometric means ratio (95% confidence interval) for cyclosporine plus methoxsalen/cyclosporine alone was 1.14 (1.02, 1.27), and treatments were therefore not bioequivalent. Methoxsalen causes a clinically significant interaction with cyclosporine in some susceptible individuals. The reasons for susceptibility and the clinical implications for chronic cyclosporine administration have not been established. Caution is recommended in combination therapy, and more frequent monitoring of cyclosporine plasma levels and clinical monitoring is advised.

Relationship between IL-1A polymorphisms and gingival overgrowth in renal transplant recipients receiving Cyclosporin A

AIM

Levels of interleukin-1alpha (IL-1alpha) are elevated in periodontal inflammation. IL-1A gene polymorphisms are associated with inflammatory diseases. This study aimed to investigate IL-1A gene polymorphism in Cyclosporin A (CsA)-treated renal transplant patients and investigate the association between this polymorphism and gingival crevicular fluid (GCF) levels of several cytokines.

MATERIALS AND METHODS

Fifty-one renal transplant patients on CsA treatment (25 with and 26 without gingival overgrowth) and 29 healthy controls were recruited for the study. Demographic, pharmacological and periodontal parameters were recorded and gingival overgrowth was assessed.

RESULTS

Multiple regression analysis showed that genotype was significantly associated with gingival overgrowth (p=0.02). Carriage of the IL-1A (-889) T allele was strongly protective [95% confidence interval (CI): 0.046-0.77], although not significantly associated with IL-1alpha protein levels in GCF. IL-1alpha, IL-1beta and IL-8, but not IL-6, were detected in GCF of CsA-treated patients, but none of them was significantly associated with gingival overgrowth.

CONCLUSIONS

This study is the first to associate a gene polymorphism as a risk factor for CsA-induced gingival overgrowth in renal transplant patients, demonstrating that IL-1A polymorphism might alter individual susceptibility to CsA. However, there was no association between GCF cytokine levels and the presence of gingival overgrowth or patient IL-1A genotype.

Comparative bioavailability of the microemulsion formulation of cyclosporine (Neoral) with a generic dispersion formulation (Cicloral) in young healthy male volunteers

The aim of this study was to compare the bioavailability of cyclosporine (CyA) from the generic dispersion formulation Cicloral (CIC) with the microemulsion formulation Neoral (NEO) and the original Sandimmune (SIM) capsules after single doses of 100, 300, or 600 mg of drug, respectively. The study was performed according to an open 3-period cross-over design with 12 young healthy male volunteers for each dosage. The concentrations of CyA and its main metabolites were determined by high performance liquid chromatography in whole blood and urine up to 48 hours postdosing. Peak concentrations and area under the time-concentration curve were greater for the NEO and CIC formulations compared with SIM, and the mean bioavailability of CIC was significantly (P<0.05) lower compared with NEO. The bioavailability of SIM compared with NEO was 54% to 71%, in agreement with previous results. Bioequivalence was not demonstrated between CIC (test) and NEO (reference) as the 90% confidence intervals were outside the 80% to 125% guidelines based on log-transformed AUCs, and were 75.2% to 87.7% at 100 mg, 79.2% to 91.8% at 300 mg, and 76.6% to 94.5% at 600 mg doses. The respective values for Cmax were 78.9% to 94.6%, 80.7% to 95.0%, and 71.4% to 84.1%. A good correlation was demonstrated between the urinary recovery of CyA and the AUC4. Therefore, the urinary recovery of CyA may be helpful as a surrogate parameter for the systemic exposure of patients to CyA. Whereas the relative amount of hydroxylated metabolites (AM1, AM9, AM1c) was similar for all formulations and doses, the urinary recovery of the N-demethylated metabolite AM4N decreased with increasing dose indicating saturable metabolism. No relationship could be demonstrated between CYP3A activity using dextromethorphan as a probe for the metabolic clearance of CyA.

Three generations of cyclosporine a formulations: an in vitro comparison

When the microemulsion formulation of the critical dose drug cyclosporine A (CsA) (Sandimmun Optoral) was introduced in the mid-1990s, it became clear that this new formulation improves the oral bioavailability of CsA and has a positive influence on its pharmacokinetic variability. Previous studies with the original CsA formulation (Sandimmun) showed that the size of the emulsion droplets and concomitant food intake has an effect on the absorption of CsA from the small intestine when orally administered. It was suggested that these effects might have an influence on the drugs' pharmacokinetic parameters. In this study, we focused on the two above-mentioned aspects and compared the first and second generations of CsA products (Sandimmun, Sandimmun Optoral) to generic CsA formulations by analyzing the contents of cyclosporine A gel capsules with respect to their emulsion droplet and micelle sizes using photon correlation spectroscopy (PCS). We tried to discern any differences in droplet size between different generations of CsA formulations, primarily the second and third generation, through simple physical tests. Because a high fat content food may influence the absorption of CsA, we also determined the distribution of CsA between hydrophilic and lipophilic phases using high-performance liquid chromatography analysis. It became clear that when compared under simple physical conditions, established cyclosporine formulations and new generic products show significant differences in droplet size and distribution between an aqueous phase and a high fat content food. Whether these differences are of clinical relevance remains to be investigated.

A fluorescence polarization-based assay for peptidyl prolyl cis/trans isomerase cyclophilin A

Peptidyl prolyl cis/trans isomerase cyclophilin A (CypA) serves as a cellular receptor for the important immunosuppressant drug, cyclosporin A. In addition, CypA and its enzyme family have been found to play critical roles in a variety of biological processes, including protein trafficking, HIV and HCV infection/replication, and Ca(2+)-mediated intracellular signaling. For these reasons, cyclophilins have emerged as potential drug targets for several diseases. Therefore, it is extremely important to screen for novel small molecule cyclophilin inhibitors. Unfortunately, the biochemical assays reported so far are not adaptable to a high-throughput screening format. Here, we report a fluorescence polarization-based assay for human CypA that can be adapted to high-throughput screening for drug discovery. The technique is based on competition and uses a fluorescein-labeled cyclosporin A analog and purified human CypA to quantitatively measure the binding capacity of unlabeled inhibitors. Detection by fluorescence polarization allows real-time measurement of binding ratios without separation steps. The results obtained demonstrated significant correlation among assay procedures, suggesting that the application of fluorescence polarization in combination with CypA is highly advantageous for the accurate assessment of inhibitor binding.

Lipoic acid supplementation prevents cyclosporine-induced hypertension and nephrotoxicity in spontaneously hypertensive rats

BACKGROUND

Cyclosporine (CsA) has significantly improved long-term survival after organ transplantations. Hypertension and nephrotoxicity are common side effects during CsA treatment and are aggravated by high salt intake.

OBJECTIVE

To examine whether lipoic acid (LA), a natural antioxidant that scavenges reactive oxygen species and regenerates/recycles endogenous antioxidants, could prevent CsA-induced hypertension and nephrotoxicity.

METHODS

Six-week-old spontaneously hypertensive rats (SHR) on a high-sodium diet (NaCl 6%) received CsA [5 mg/kg subcutaneously (s.c.)] alone or in combination with LA (0.5% w/w) for 6 weeks. Blood pressure, arterial functions, and tissue morphology were determined. Immunohistochemistry, quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and high-pressure liquid chromatography were used for kidney and heart samples.

RESULTS

CsA induced severe hypertension, cardiac hypertrophy, endothelial dysfunction, and pronounced albuminuria. Histologically, the kidneys showed severe thickening of the media of the afferent arteries with fibrinoid necrosis, perivascular monocyte/macrophage infiltration and nitrotyrosine overexpression. CsA induced the expression of fibrogenic connective tissue growth factor both in the heart and kidneys. The detrimental effects of CsA were associated with upregulation of myocardial atrial natriuretic peptide (ANP) mRNA expression, paradoxical activation of the renin-angiotensin system (RAS), induction of renal reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase, and overexpression of oxidative stress-induced transcription factor NRF2. LA lowered blood pressure, ameliorated cardiac hypertrophy and endothelial dysfunction, and totally normalized albuminuria. In LA-treated rats, renal and cardiac morphologies were indistinguishable from those of SHR controls. CsA-induced myocardial ANP and connective tissue growth factor (CTGF) mRNA overexpression, RAS activation, NADPH oxidase induction, and NRF2 overexpression were prevented by LA. LA induced the mRNA expression of gamma-glutamylcysteine ligase, the rate-limiting enzyme in glutathione synthesis, and markedly increased hepatic cysteine and glutathione concentrations.

CONCLUSIONS

Our findings suggest a salutary role for lipoic acid supplementation in the prevention of CsA-induced hypertension and nephrotoxicity, and underscore the importance of increased oxidative stress in the pathogenesis of CsA toxicity.

Intrarenal blood oxygenation and renal function measured by magnetic resonance imaging during long-term cyclosporine treatment

Treatment with cyclosporine (CsA) markedly affects the renin-angiotensin-aldosterone system in parallel with an increase in the net tubular reabsorption or a decrease in secretion. Since tubular reabsorption is closely linked to medullary oxygen consumption, the aim of the present study was to investigate the intrarenal oxygenation and renal function in response to CsA. Six mini Göttingen pigs were treated with CsA (10 mg/kg/d) for 6 months. The intrarenal oxygenation was indirectly measured as R2* obtained with a multiecho gradient-echo magnetic resonance imaging (MRI) sequence. Single-kidney renal blood flow (skRBF) was measured by a velocity-sensitive gradient-echo MRI sequence. Relative single-kidney glomerular filtration rate (rskGFR) was derived from the MRI time-activity curve in response to an intravenous bolus of Gd-DTPA (0.05 mmol/kg). The present study showed that administration of CsA increased the medullary R2* (23.1 Hz vs 19.0 Hz, P = .002), whereas R2* was slightly increased in the renal cortex (13.3 Hz vs 12.3 Hz, P = .012). In parallel, rskGFR increased significantly (47.2 mL/min vs 19.8 mL/min, P = .005) but skRBF was unchanged (197.6 mL/min vs 202.5 mL/min, P > .05). The increased R2* in the renal medulla indicated that CsA augments the tubular reabsorption of water, leading to increased oxygen consumption. The supply of oxygen to the kidney was, however, maintained during treatment with CsA as suggested by an unchanged renal blood flow. The increased tubular reabsorption was compensated for by an elevated glomerular filtration rate.

Ciliary tissue transplantation in the rabbit

Irreversible damage of the ciliary body can be responsible for prolonged ocular hypotony and phthisis bulbi, which, currently, cannot be treated. The aim of this study was to achieve survival of morphologically normal ciliary tissue (CT) transplants in the anterior chamber of a rabbit's eye. Outbred female New Zealand albino rabbits received CT allografts, which were placed on to the surface of the host iris. We evaluated the influence of ciclosporin (CsA), VEGF and donor perfusion on graft survival. Operated eyes were assessed clinically and histologically, and revascularization of the grafts was determined by fluorescein angiography. All grafts became dark and ischemic during the first five to seven days after transplantation. Reperfusion of the grafted tissue was complete at approximately ten days after transplantation. In untreated animals, transplants became infiltrated by inflammatory cells, which led to destruction of the tissue. This was prevented by systemic use of CsA. Transplants treated with VEGF prior to transplantation had fewer ischemic areas but epithelial cell survival was not improved. Whole body donor perfusion prior to preparation of the grafts resulted in less inflammation and, histologically, in a better quantity and quality of the epithelial cells in the CT transplants. Ciliary tissue can be successfully transplanted but the ciliary epithelium suffers from ischemia and in untreated animals the whole transplant is rejected in the classical fashion. If the donor is perfused and the host immunosuppressed, histologically normal ciliary epithelium can be preserved together with rapid revascularization, minimal inflammation and good survival of the transplant, although fibrosis continued to occur during the two months after transplantation.

Are neurodegenerative disorders systemic diseases? Outlook for future immune-based therapies

The prevalence of neurodegenerative diseases increases exponentially with age. Increasing life expectancies in Western countries have, therefore, been accompanied by a growing increase in the number of victims, and in the future we can expect to see an increased number of the geriatric population suffering from these diseases. Despite improvements in our understanding of the pathogeneses, the prospects for finding a cure remain bleak. Many questions remain unanswered: are we dealing with a family of diseases or with individual unrelated syndromes? Is there a systemic malfunction that operates via a common pathway but affects different tissues or organs in different individuals? How will the answers to these questions affect future therapy?

Polymeric micelles for the solubilization and delivery of cyclosporine A: pharmacokinetics and biodistribution

The aim of this study was to assess the potential of polymeric micelles to modify the pharmacokinetics and tissue distribution of cyclosporine A (CsA). Drug-loaded methoxy poly(ethylene oxide)-b-poly(epsilon-caprolactone) (PEO-b-PCL) micellar solutions in isotonic medium were prepared and administered intravenously to healthy Sprague-Dawley rats. Blood and tissues were harvested and assayed for CsA, and resultant pharmacokinetic parameters and tissue distribution of CsA in its polymeric micellar formulation were compared to its commercially available intravenous formulation (Sandimmune). In the pharmacokinetic assessment, a 6.1 fold increase in the area under the blood concentration versus time curve (AUC) was observed for CsA when given as polymeric micellar formulation as compared to Sandimmune. The volume of distribution and clearance of CsA as PEO-b-PCL formulation were observed to be 10.0 and 7.6 fold lower, respectively, compared to the commercial formulation. No significant differences in t(1/2) or MRT could be detected. In the biodistribution study, analysis of tissue samples indicated that the mean AUC of CsA in polymeric micelles was lower in liver, spleen and kidney (1.5, 2.1 and 1.4-fold, respectively). Similar to the pharmacokinetic study in these rats, the polymeric micellar formulation gave rise to 5.7 and 4.9-fold increase in the AUC of CsA in blood and plasma, respectively. Our results show that PEO-b-PCL micelles can effectively solubilize CsA, at the same time confining CsA to the blood circulation and restricting its access to tissues such as kidney, perhaps limiting the onset of toxicity.