A randomized trial of nasal spray salmon calcitonin in postmenopausal women with established osteoporosis: the prevent recurrence of osteoporotic fractures study. PROOF Study Group

PURPOSE

We conducted a 5-year, double-blind, randomized, placebo-controlled study to determine whether salmon calcitonin nasal spray reduced the risk of new vertebral fractures in postmenopausal women with osteoporosis.

SUBJECTS AND METHODS

A total of 1,255 postmenopausal women with established osteoporosis were randomly assigned to receive salmon calcitonin nasal spray (100, 200, or 400 IU) or placebo daily. All participants received elemental calcium (1,000 mg) and vitamin D (400 IU) daily. Vertebral fractures were assessed with lateral radiographs of the spine. The primary efficacy endpoint was the risk of new vertebral fractures in the salmon calcitonin nasal spray 200-IU group compared with the placebo group.

RESULTS

During 5 years, 1,108 participants had at least one follow-up radiograph. A total of 783 women completed 3 years of treatment, and 511 completed 5 years. The 200-IU dose of salmon calcitonin nasal spray significantly reduced the risk of new vertebral fractures by 33% compared with placebo [200 IU: 51 of 287, placebo: 70 of 270, relative risk (RR) = 0.67, 95% confidence interval (CI): 0.47- to 0.97, P = 0.03]. In the 817 women with one to five prevalent vertebral fractures at enrollment, the risk was reduced by 36% (RR = 0.64, 95% CI: 0.43- to 0.96, P = 0.03). The reductions in vertebral fractures in the 100-IU (RR = 0.85, 95% CI: 0.60- to 1.21) and the 400-IU (RR = 0.84, 95% CI: 0.59- to 1.18) groups were not significantly different from placebo. Lumbar spine bone mineral density increased significantly from baseline (1% to 1. 5%, P<0.01) in all active treatment groups. Bone turnover was inhibited, as shown by suppression of serum type-I collagen cross-linked telopeptide (C-telopeptide) by 12% in the 200-IU group (P <0.01) and by 14% in the 400-IU group (P<0.01) as compared with placebo.

CONCLUSION

Salmon calcitonin nasal spray at a dose of 200 IU daily significantly reduces the risk of new vertebral fractures in postmenopausal women with osteoporosis.

Surface-modified PLGA nanosphere with chitosan improved pulmonary delivery of calcitonin by mucoadhesion and opening of the intercellular tight junctions

Surface-modified DL-lactide/glycolide copolymer (PLGA) nanospheres with chitosan (CS) were prepared by the emulsion solvent diffusion method for pulmonary delivery of peptide, i.e., elcatonin. The nanosphere suspension was successfully aerosolized with a nebulizer similar to the drug solution, whereas the microsphere suspensions could not be aerosolized. After pulmonary administration, CS-modified PLGA nanospheres were more slowly eliminated from the lungs than unmodified PLGA nanospheres. CS-modified PLGA nanospheres loaded with elcatonin reduced blood calcium levels to 80% of the initial calcium concentration and prolonged the pharmacological action to 24 h, which was a significantly longer duration of action than that by CS-unmodified nanospheres. These results were attributed to the retention of nanospheres adhered to the bronchial mucus and lung tissue and sustained drug release at the adherence site. In addition, CS and CS on the surface of the nanospheres enhanced the absorption of drug. The rank order of the absorption of the model drugs with CS solution was carboxyfluorescein>FITC-dextran-4 (FD-4; Mw. 4000)>FD-21 (Mw. 21,000)>FD70 (Mw. 70,000), which corresponded to the molecular weights ([Mw.] given in parentheses). The absorption-enhancing effect may have been caused by opening the intercellular tight junctions.

Chitosan–PEG nanocapsules as new carriers for oral peptide delivery

We have previously reported the ability of chitosan nanocapsules to enhance and prolong the oral absorption of peptides. In the present work, our goal was to design a new type of nanocapsules, using chitosan chemically modified with poly(ethylene glycol) (PEG) (0.5% and 1% pegylation degree) and to investigate the consequences of this modification on the in vitro and in vivo behaviour of the nanocapsules. Chitosan-PEG nanocapsules and the control PEG-coated nanoemulsions were obtained by the solvent displacement technique. Their size was in the range of 160-250 nm. Their zeta potential was greatly affected by the nature of the coating, being positive for chitosan-PEG nanocapsules and negative in the case of PEG-coated nanoemulsions. The presence of PEG, whether alone or grafted to chitosan, improved the stability of the nanocapsules in the gastrointestinal fluids. Using the Caco-2 model cell line it was observed that the pegylation of chitosan reduced the cytotoxicity of the nanocapsules. In addition, these nanocapsules did not cause a significant change in the transepithelial resistance of the monolayer. Finally, the results of the in vivo studies showed the capacity of chitosan-PEG nanocapsules to enhance and prolong the intestinal absorption of salmon calcitonin. Additionally, they indicated that the pegylation degree affected the in vivo performance of the nanocapsules. Therefore, by modulating the pegylation degree of chitosan, it was possible to obtain nanocapsules with a good stability, a low cytotoxicity and with absorption enhancing properties.

Mucoadhesive properties of carbopol or chitosan-coated liposomes and their effectiveness in the oral administration of calcitonin to rats

Mucoadhesive liposomes were prepared by coating multilamellar liposomes with Carbopol (CP) in a similar manner to that used in the preparation of chitosan-coated liposomes (CS-Lip) previously reported [Takeuchi et al., Chem. Pharm. Bull. 42 (1994) 1954-1956; Pharm. Res. 13 (1996) 896-901]. The positively charged liposomes containing dipalmitoylphosphatidylcholine (DPPC) and stearylamine at an optimum formulation ratio (40:1) could be coated with CP without aggregation of the liposomal particles during the coating process. The mucoadhesive properties of both the resultant polymer-coated liposomes (CP-Lip and CS-Lip) and the positively or negatively charged noncoated liposomes (Non-Lip) were evaluated using the rat intestine. The order was CS-Lip> or = CP-Lip>positively charged Non-Lip>negatively charged Non-Lip. The adhesive property of CP-Lip decreased on increasing pH of the dispersing medium from pH 5.0 to 7.4, probably owing to the electric repulsion between CP-Lip and the mucus layer. The effectiveness of the liposomal formulations in oral administration of calcitonin was evaluated by measuring the change in the blood calcium concentration of rats. Administration of CP-Lip and CS-Lip containing calcitonin showed an enhanced and prolonged reduction in blood calcium concentration. The overall pharmacological effect of CP- and CS-Lips evaluated by means of the area under the plasma calcium concentration curve was 2.4 and 2.8 times higher than that of negatively and positively charged Non-Lips, respectively.

Procalcitonin to guide initiation and duration of antibiotic treatment in acute respiratory infections: an individual patient data meta-analysis

BACKGROUND

Procalcitonin algorithms may reduce antibiotic use for acute respiratory tract infections (ARIs). We undertook an individual patient data meta-analysis to assess safety of this approach in different ARI diagnoses and different clinical settings.

METHODS

We identified clinical trials in which patients with ARI were assigned to receive antibiotics based on a procalcitonin algorithm or usual care by searching the Cochrane Register, MEDLINE, and EMBASE. Individual patient data from 4221 adults with ARIs in 14 trials were verified and reanalyzed to assess risk of mortality and treatment failure-overall and within different clinical settings and types of ARIs.

RESULTS

Overall, there were 118 deaths in 2085 patients (5.7%) assigned to procalcitonin groups compared with 134 deaths in 2126 control patients (6.3%; adjusted odds ratio, 0.94; 95% confidence interval CI, .71-1.23)]. Treatment failure occurred in 398 procalcitonin group patients (19.1%) and in 466 control patients (21.9%; adjusted odds ratio, 0.82; 95% CI, .71-.97). Procalcitonin guidance was not associated with increased mortality or treatment failure in any clinical setting or ARI diagnosis. Total antibiotic exposure per patient was significantly reduced overall (median [interquartile range], from 8 [5-12] to 4 [0-8] days; adjusted difference in days, -3.47 [95% CI, -3.78 to -3.17]) and across all clinical settings and ARI diagnoses.

CONCLUSIONS

Use of procalcitonin to guide initiation and duration of antibiotic treatment in patients with ARIs was effective in reducing antibiotic exposure across settings without an increase in the risk of mortality or treatment failure. Further high-quality trials are needed in critical-care patients.

Calcitonin: inhibitory effect on eating in rats

Subcutaneous and intracerebral injections of calcitonin inhibited feeding in rats. The anorectic activity of calcitonin was destroyed by exposing the hormone to heat, trypsin, or hydrogen peroxide. Calcitonin did not produce a conditioned taste aversion to saccharin, and maximum inhibition of feeding occurred 4.5 to 8.3 hours after subcutaneous administration. It is concluded that calcitonin inhibits feeding by acting directly on the central nervous system.

Mucoadhesive DL-lactide/glycolide copolymer nanospheres coated with chitosan to improve oral delivery of elcatonin

The purpose of this work was to develop a novel mucoadhesive DL-lactide/glycolide copolymer (PLGA) nanosphere system to improve peptide absorption and prolong the physiological activity following oral administration. The desired PLGA nanospheres with elcatonin were prepared by the emulsion solvent diffusion method to coat the surface of the resultant nanospheres with a mucoadhesive polymer such as chitosan, poly(acrylic acid), and sodium alginate. Their mucoadhesive properties were evaluated by measuring the nanospheres adsorbed to a rat everted intestinal sac (in vitro). The chitosan-coated nanospheres showed higher mucoadhesion to the everted intestinal tract in saline than the other polymer-coated nanospheres. There was no mucoadhesion site-specificity of the chitosan-coated nanospheres between duodenal, jejunal, and ileal sacs. The payload of drug in the chitosan-coated nanospheres was successfully increased by using the solvent diffusion method in oil. The pattern of drug release of the resultant nanospheres did not differ markedly from that of uncoated nanospheres. The chitosan-coated nanospheres with elcatonin were administered intragastrically to fasted Wistar rats. The chitosan-coated nanosphere reduced significantly the blood calcium level compared with elcatonin solution and uncoated nanospheres, and the reduced calcium level was sustained for a period of 48 hr. Even under nonfasting conditions, the mucoadhesion of chitosan-coated nanospheres was unaltered and the reduction in blood Ca levels was maintained satisfactorily.

Effect of calcitonin and glutocorticoids in combination on the hypercalcemia of malignancy

The effects of the combination of glucocorticoids and calcitonin on serum calcium levels were compared with the responses to calcitonin alone in 14 patients with malignant disease and hypercalcemia. The serum calcium concentrations of those patients treated with calcitonin alone returned to pretreatment concentrations within 48 hours, whereas those treated with the combination of calcitonin and glucocorticoids maintained the lower serum calcium concentrations for more than 4 days. These results suggest that the combination of calcitonin and glucocorticoids is a rapidly effective form of medical treatment for hypercalcemia and that glucocorticoids help to maintain the acute response to calcitonin in patients with hypercalcemia.

1-Year controlled randomised trial of prevention of early postmenopausal bone loss by intranasal calcitonin

79 women who had been menopausal for less than 36 months and who had not received any form of treatment to prevent bone loss were randomly assigned to a 12-month regimen of calcium 500 mg/day or calcium 500 mg plus intranasal salmon calcitonin 50 IU/day for 5 days per week. After 12 months of treatment bone mineral density had decreased in the calcium-only group by a mean of 3.16 (SEM 0.6)% (p less than 0.01) but had increased in the calcium plus calcitonin group by 1.38 (0.8)% (NS). The difference in response between the two treatment groups was also highly significant (p less than 0.01), as was the difference between values for hydroxyprolinuria/creatininuria (p less than 0.01). Endogenous calcitonin levels rose significantly in the calcium group but remained unchanged in calcitonin-treated patients. Treatment by calcitonin and calcium was not followed by increased secretion of parathyroid hormone. The findings suggest that intranasal calcitonin can counteract early postmenopausal bone loss.

Nasal calcitonin for treatment of established osteoporosis

Thirty-seven women with established osteoporosis completed a one-year double-blind, placebo-controlled study with the primary aim of examining the effect of nasal salmon calcitonin (200 IU daily) on bone and calcium metabolism. All the women received a daily calcium supplement of 500 mg. For comparison we also report data from an age-matched group of healthy women who did not receive calcium supplementation. The bone mineral measured in the forearm (single photon absorptiometry) and spine (dual photon absorptiometry) showed a similar pattern during treatment. The calcitonin group (n = 17) did not lose bone mineral in comparison with the placebo (n = 20) and the control groups (n = 19) (P less than 0.01). The biochemical estimates of both bone resorption and bone formation decreased highly significantly in the calcitonin group (P less than 0.001) and were unchanged in the control group, whereas the placebo (calcium) group showed intermediate values. Neither subjective nor objective side-effects occurred in any of the groups. We conclude that nasal calcitonin is a realistic treatment of established osteoporosis.

Comparison of aminohydroxypropylidene diphosphonate, mithramycin, and corticosteroids/calcitonin in treatment of cancer-associated hypercalcaemia

Thirty-nine patients with cancer-associated hypercalcaemia were randomly allocated to receive aminohydroxypropylidene diphosphonate (APD), mithramycin, or corticosteroids and salmon calcitonin. Corticosteroids/calcitonin had the fastest calcium-lowering effect, owing mainly to an acute reduction in renal tubular calcium reabsorption; continued therapy over 9 days failed to suppress accelerated bone resorption, however, and most patients remained hypercalcaemic. Mithramycin also substantially reduced serum calcium within 24 h. A further dose on day 2 generally controlled hypercalcaemia until day 6 by reducing both bone resorption and renal tubular calcium reabsorption. By day 9, however, about 50% of the mithramycin-treated patients had started to relapse as bone resorption increased again. With APD serum calcium levels fell more slowly but progressively owing to effective suppression of bone resorption; by day 9 the control of hypercalcaemia was significantly better than in the other treatment groups. Symptoms of hypercalcaemia were greatly relieved, especially by APD.

Intraventricular calcitonin inhibits gastric acid secretion

Parenteral and intracerebroventricular administration of calcitonin in rats resulted in the suppression of gastric acid secretion. This suppression also occurred in rats with insulin-induced hypoglycemia and after the administration of thyrotropin-releasing hormone. Intracerebroventricularly administered calcitonin was 1000 times more effective than parenterally administered calcitonin in suppressing gastric acid secretion. Calcitonin also inhibited the development of stress-induced ulcers in rats.

Analgesic effect of salmon calcitonin in osteoporotic vertebral fractures: a double-blind placebo-controlled clinical study

Back pain due to vertebral collapse is the main symptom of postmenopausal osteoporosis. The clinical picture in these crush fractures varies, depending on the type and the location of fracture, but in general, a new vertebral crush fracture gives rise to severe pain that immobilizes the patient and necessitates bedrest. In this double-blind controlled clinical trial, 56 patients who had recently (within the last 3 days) suffered an osteoporotic vertebral fracture were hospitalized for a period of 14 days. Salmon calcitonin (100 IU) or placebo injections were given daily. Pain was rated daily on a 10-point scale by the same observers. Blood and urinary parameters were also evaluated. The results showed a significant (P less than 0.001) difference in pain intensity between the calcitonin group and the placebo group. This beneficial effect was generally apparent from the second day of treatment onward, and over the following 2 weeks, the patients were able to sit and stand, and gradually started to walk again. A significant decrease in urinary hydroxyproline and urinary calcium was also noted in the calcitonin group. It is concluded that calcitonin exerts a beneficial effect on back pain following a vertebral crush fracture.

Effectiveness of submicron-sized, chitosan-coated liposomes in oral administration of peptide drugs

The mucoadhesive behavior of chitosan-coated liposomes in the intestinal tract of the rat was examined to elucidate their particle size effects on the absorption of an entrapped drug, calcitonin. The intestine was removed from rats after oral administration of liposomes containing a fluorescent dye, and its various parts were observed with confocal laser scanning microscopy. Penetration of submicron-sized liposomes (ssLip) or chitosan-coated ssLip (ssCS-Lip) into the mucosa was observed, while such behavior was not observed for the multilamellar liposomes, even when coated with chitosan (CS-Lip). The retentive property of ssCS-Lip was confirmed by measuring the amount of dye in each part of the intestine. The pharmacologic effects of calcitonin-loaded liposomes of different particle size were measured after oral administration in rats. The pharmacologic effect of oral administration of ssLip coated with chitosan was detected up to 120 h after administration. The extensive pharmacologic effect of ssCS-Lip was attributed to their prolonged retention in the intestinal mucosa, partly owing to their penetrative property into the intestinal mucosa. The chitosan-coated ssLip, with their higher retentive property in the intestinal tract, are much more effective than ssLip and CS-Lip in improving the enteral absorption of peptide drugs.

Effect of salcatonin given intranasally on early postmenopausal bone loss

OBJECTIVE

To study the effect of salmon calcitonin (salcatonin) given intranasally on calcium and bone metabolism in early postmenopausal women.

DESIGN

Double blind, placebo controlled, randomised group comparison.

SETTING

Outpatient clinic for research into osteoporosis.

SUBJECTS

52 Healthy women who had had a natural menopause two and a half to five years previously.

INTERVENTIONS

The 52 women were allocated randomly to two years of treatment with either salcatonin 100IU given intranasally (n = 26) or placebo (n = 26). Both groups received a calcium supplement of 500 mg daily. Seven of the women receiving salcatonin and six of those receiving placebo left the study before its end.

MAIN OUTCOME MEASURES

Bone mineral content in the spine, the total skeleton, and the forearms after two years of treatment.

RESULTS

Bone mineral content in the spine was significantly higher in the women who had received salcatonin than in those who had received placebo both after one year and after two years of treatment. After one year the difference was 3.8% (95% confidence interval 0.0 to 7.6%) and after two years it was 8.2% (3.8 to 12.6%). In contrast, the bone mineral content in the distal and proximal forearms and in the total skeleton declined similarly in both groups by about 2% each year, and after two years of treatment the differences between the groups were not significant. Biochemical estimates of bone turnover were not affected by salcatonin.

CONCLUSION

The results suggest that salcatonin given intranasally in the dose used prevents bone loss in the spine of early post menopausal women but does not affect the peripheral skeleton.

An evaluation of antibodies and clinical resistance to salmon calcitonin

21 patients with Paget's disease of bone and one with osteoporosis were studied to detect development of antibodies to salmon calcitonin during chronic therapy. Antibody titers ranged from 1:40 to 1:30,000 in plasma obtained after treatment of 11 patients. Radio-immunoelectrophoresis revealed that the antibodies were restricted to the gammaG class. One patient, W. O., with Paget's disease initially responded to treatment with a decrease in bone turnover, but later became resistant to the hormone in association with the appearance of a very high titer (1:30,000) of antibody against salmon calcitonin. A 1:10 dilution of his plasma was shown to completely inactivate 20 mMRC units/ml of salmon calcitonin as detected by bioassay in rats; slight inactivation was detected at a 1:200 dilution. All other patients continued to respond to salmon calcitonin despite the development of antibody to the hormone in ten cases. No evidence of systemic allergic reactions or other toxicity was found in any patient. The data suggest that although antibody formation may occur in as many as 50% of patients treated with salmon calcitonin, this antibody response is unlikely to be of clinical significance in most patients. However, in an occasional patient, a marked antibody response may occur which interferes with the therapeutic use of the hormone.

Calcitonin for prevention of postmenopausal bone loss

A 2-year randomised pilot study was conducted in 70 patients to see whether the osteoclast-inhibiting effect of calcitonin would reduce postmenopausal vertebral bone loss. An oestradiol-treated group was included in the study as a positive control since oestrogens are known to be effective. Calcitonin reduced vertebral bone loss in doses above 250 micrograms human calcitonin (50 international units) a week, and at this dose was as effective as oestradiol.

A comparative study of the potential of solid triglyceride nanostructures coated with chitosan or poly(ethylene glycol) as carriers for oral calcitonin delivery

We have previously reported the formation and characterization of poly(ethylene glycol) (PEG)-coated and chitosan (CS)-coated lipid nanoparticles. In the present work our goal was to study the interaction of these surface-modified lipid nanoparticles with Caco-2 cells and to evaluate the potential of these nanostructures as oral delivery systems for salmon calcitonin (sCT). The interaction of rhodamine-loaded nanoparticles with the Caco-2 cell monolayers was evaluated quantitatively and qualitatively by confocal laser scanning microscopy and fluorimetry, respectively. The ability of these nanoparticles to reversibly enhance the transport of hydrophilic macromolecules through the monolayers was investigated by measuring the transepithelial electric resistance and the permeability to Texas Red-dextran. Finally, in vivo studies of the response to sCT-loaded nanoparticles were performed in rats. The results showed that the association of rhodamine-loaded nanoparticles to the Caco-2 cell monolayer was independent of the surface coating of the nanoparticles (CS-coated versus PEG-coated nanoparticles). However, while PEG-coated nanoparticles did not affect the permeability of Caco-2 monolayers, CS-coated nanoparticles produced a dose-dependent reduction in the transepithelial electric resistance, simultaneously to an enhanced dextran transport. The results obtained following oral administration of sCT-loaded CS-coated nanoparticles to rats showed a significant and prolonged reduction in the serum calcium levels as compared to those obtained for control (sCT solution). In contrast, the hypocalcemic response of sCT-loaded PEG-coated nanoparticles was not significantly different of that provided by the control (sCT solution). Therefore, these results indicate that the surface composition of the particles is a key factor in the improvement of the efficiency of oral sCT formulations. Moreover, the encouraging results obtained for CS-coated nanoparticles underline their potential as carriers for peptide delivery.

Hydrogels for oral delivery of therapeutic proteins

In recent years there has been significant new interest in the development of transmucosal (mostly oral) pharmaceutical formulations for the delivery of therapeutic proteins. Emphasis has been given to the molecular design of new carriers for the delivery of insulin, calcitonin and various types of interferons for the treatment of diabetes, osteoporosis, multiple sclerosis and cancer. Most popular carriers include advanced designs of swollen hydrogels prepared from neutral or intelligent polymeric networks. In this review, the most successful of such systems are presented and their promise in the field described.

Enhanced intestinal absorption of salmon calcitonin (sCT) from proliposomes containing bile salts

PURPOSE

The feasibility of using proliposomes containing salmon calcitonin (sCT) and absorption enhancing agents, as an oral delivery system, to improve the intestinal absorption of sCT was explored using rats and Caco-2 cell systems.

METHODS

Seventeen surfactants were examined for their effects with reference to accelerating the permeability of sCT (300 microg/ml) across Caco-2 cell monolayers, and damage to the intestinal epithelial cells, as measured by the change in transepithelial electrical resistance (TEER) across the cell monolayer. Proliposomes containing sCT (0.75%, w/w) and sodium taurodeoxycholate (NaTDC, 2.5%, w/w) (TDC proliposomes) were prepared according to the standard method using sorbitol and phosphatidylcholine as core and wall-forming materials, respectively, administered intra-duodenally to rats, and plasma concentrations of sCT were subsequently determined by LC-MS.

RESULTS

Among the surfactants examined, some bile salts including NaTDC appeared to be the most advantageous when estimated based on the balance between the permeation enhancement (e.g., a 10.8-fold increase in the permeability of sCT for 0.1% NaTDC) and damage to the cells (e.g., a 3.55-fold decrease in the TEER value for 0.1% NaTDC). The administration of TDC proliposomes resulted in a 7.1-fold increase in the bioavailability (i.e., 0.49%) of sCT, when administered duodenally to rats. The size of the reconstituted liposomes in water was significantly smaller (e.g., 23.2 nm, number weighted diameter), and the entrapment efficiency (EE) of sCT in the reconstituted liposomes was 2.8-fold larger (54.9%), for TDC proliposomes, compared to proliposomes prepared without NaTDC (sCT proliposomes).

CONCLUSION

A 7.1-fold increase in the bioavailability of sCT could be achieved from the TDC proliposomes. In addition to the intrinsic activity of the bile salt to fluidize the membrane, the simultaneous delivery of sCT and NaTDC to the site of absorption in the intestine via proliposomes and the subsequent formation of lipophilic ion-pair complexes between sCT and NaTDC at the site might have been contributing factors in this outstanding absorption enhancement.

New surface-modified lipid nanoparticles as delivery vehicles for salmon calcitonin

The aim of the present work was to develop a new nanoparticulate system, consisting of lipid nanoparticles coated with chitosan (CS), intended for the oral administration of peptide drugs. These new nanoparticles were studied, and compared with the previously developed PEG-coated lipid nanoparticles, with regard to their ability to incorporate and deliver the model peptide salmon calcitonin (sCT). Moreover, the influence of the core composition, either a solid triglyceride (tripalmitin), or a mixture of a liquid and a solid triglyceride (Miglyol 812 and tripalmitin) on the encapsulation and release of sCT was investigated. The results showed that a CS coating could be formed around the tripalmitin nanoparticles by simple incubation of the lipid cores in a CS solution, due to the high affinity of CS for the lipid core. In addition, sCT could be efficiently associated, irrespective of the core composition, to the nanoparticles. This important association was attributed to the marked affinity of sCT for the lipid cores, as confirmed by the adsorption studies. However, the nature of the coating affected the surface association of the peptide, which was less important for the nanoparticles coated with CS, than for PEG-coated nanoparticles. This was attributed to the displacement of the sCT molecules located on the surface of the nanoparticles by the positively charged CS molecules. This reduced surface association led to a decrease in the burst release effect, which was more pronounced for the nanoparticles coated with PEG than for those coated with CS. Following the initial burst, the systems provided a continuous and slow release of the associated peptide, independently of the nature of the coating. This slow release was attributed to the affinity of the peptide for the lipids and to the absence of degradation of the lipid matrix under the in vitro release conditions.