Zeolitic imidazolate framework-90 loaded with methylprednisolone sodium succinate effectively reduces hypertrophic scar in vivo.

Hypertrophic scar (HS) is characterized by an abnormal fibroblast-myofibroblast transformation; non-apoptosis of fibroblasts; and redundant expression of TGF-ß1, VEGF, α-SMA, and collagen I/III. An HS affects patients' physical and psychological quality of life, leading to joint dysfunction and skin cancer. However, there is currently no satisfactory drug to treat this disorder. In this study, we constructed methylprednisolone sodium succinate (MPSS) encapsulated ZIF-90 (MPSS@ZIF-90) for the effective treatment of an HS. The encapsulation of MPSS in ZIF-90 can achieve the controllable drug release of MPSS and prolong its effective treatment time. MPSS@ZIF-90 enhanced the apoptosis of human hypertrophic scar fibroblasts and downregulated the overexpression of TGF-ß1, VEGF, α-SMA, and collagen I/III both in vitro and in vivo. The instant injection of MPSS@ZIF-90 effectively intervened with the formation of the HS after 28 days. On the contrary, MPSS@ZIF-90 greatly reduced the HS with two injections and 14 days of treatment after the HS was formed. This work provides evidence of effective intervention in the formation of an HS and the therapeutic effectiveness of MPSS@ZIF-90 with short treatment periods in vivo. It suggests that MPSS@ZIF-90 can be used as a biomedical option in the treatment of skin wounds and may reveal the potential molecular basis for promising future antifibrotic agents against scarring.

Therapeutic Effect of a Novel Nano-Drug Delivery System on Membranous Glomerulonephritis Rat Model Induced by Cationic Bovine Serum.

In order to explore a novel high efficacy drug delivery system for membranous glomerulonephritis (MGN), a complex chronic inflammation, methylprednisolone bovine serum albumin nanoparticles (ME BSA NPs) were designed. The nanoparticles were prepared by desolvation-chemical crosslinking method and its physicochemical characterizations were conducted. The experimental MGN rat models induced by cationic bovine serum albumin were established by a modified Border's method and applied in the pharmacodynamics study of ME BSA NPs. The results showed that the particle size, particle dispersion index, and entrapment efficiency of ME BSA NPs were 131.1 ± 3.4 nm, 0.159 ± 0.036, and 71.51 ± 1.74%, respectively. In addition, the image of transmission electron microscopy showed that the ME BSA NPs were the relatively uniform spherical particles. In the in vivo pharmacodynamics study, compared with saline group and SOLU-MEDROL® group, that the ME BSA NPs group was significantly reduced the levels of 24 h urinary protein (P < 0.01) and serum creatinine (P < 0.05). Consequently, these outcomes indicated that the nanoparticles we studied were a promising drug delivery system for the MGN disease, and it may be also useful for other complex chronic inflammations.

Ex vivo models to evaluate the role of ocular melanin in trans-scleral drug delivery.

Trans-scleral delivery is nowadays considered as a possible way to deliver drugs to the posterior segment of the eye. Despite the potentiality of this administration route, there is a lack of fundamental knowledge on the role of the numerous barriers involved. The aim of this work was to develop an easy and cheap ex vivo method to evaluate the barrier properties of the choroid-Bruch's layer and in particular to estimate the role of melanin in drug diffusion through ocular tissues. In vitro binding studies were performed to estimate drug affinity for melanin; model molecules used were methylene blue, propranolol, levofloxacin and methylprednisolone sodium succinate. The ex vivo model set up is based on porcine eye bulbs with light blue iris or brown iris. While the choroid of brown eyes is dark, the choroid of blue eyes is transparent, due to the absence of melanin. Permeation experiments using pigmented and not-pigmented porcine tissues gave the opportunity to discriminate between the barrier role of choroid-Bruch's membrane as such and the barrier role of melanin. Ex vivo permeation experiments can be performed using isolated choroid-Bruch's or the sclera-choroid-Bruch's layer. In this last case, it is possible to take into account also the barrier role of the sclera that tends to decrease the drug concentration at the sclera/choroid interface, thus amplifying the effect of melanin. The data obtained in this paper indicate that for some drugs melanin can really represent a barrier and the effect can imply a lower drug flux or simply a longer lag time depending on the kind of drug and the concentration applied. However, it is a saturable barrier, thus its effect can probably be overtaken by high doses or multiple administrations. The ex vivo model set up can help to refine computational models, to better evaluate the interplay among static, dynamic and metabolic barriers. Additionally, since human eyes display a full range of pigmentation, the model could also be useful to investigate the possible influence of pigmentation phenotype on trans-scleral delivery.

High-performance liquid-chromatographic-atmospheric-pressure chemical-ionization ion-trap mass-spectrometric identification of isomeric C6-hydroxy and C20-hydroxy metabolites of methylprednisolone in the urine of patients receiving high-dose pulse therapy.

Fourteen metabolites of methylprednisolone have been analysed by gradient-elution high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS). The compounds were separated on a Cp Spherisorb 5 microm ODS column connected to a guard column packed with pellicular reversed phase. The mobile phase was an acetonitrile- 1.0% aqueous acetic acid gradient at a flow rate of 1.5 mL min(-1) The analysis gave a complete picture of parent drug, prodrugs and metabolites, and the alpha/beta stereochemistry was resolved. The short (1-2 h) elimination half-life of methylprednisolone is explained by extensive metabolism. The overall picture of the metabolic pathways of methylprednisolone is apparently simple-reduction of the C20 carbonyl group and further oxidation of the C20,C21 side chain (into C21COOH and C20COOH), in competition with or in addition to oxidation at the C6 position.

Methylprednisolone-hemisuccinate and its metabolites in serum, urine and bile from two patients with acute graft rejection.

Methylprednisolone-hemisuccinate (MPHS), methylprednisolone (MP), 20-alpha-hydroxy- (20 alpha HMP) and 20-beta-hydroxymethyl-prednisolone (20 beta HMP) concentrations were measured in serum, urine and bile from two liver transplant recipients who had received 1 g MPHS by a 1 h intravenous infusion for treatment of an acute rejection episode. These patients excreted similar total amounts of the dose in urine as patients with rheumatoid arthritis (historical controls) who had normal liver function. The transplant patients showed a ratio in urine of 'total metabolites'/MPHS that was one third that of patients with rheumatoid arthritis. Less than 0.2% of the administered MPHS appeared in bile as MPHS, MP, 20 alpha HMP and 20 beta HMP during the 24 h following infusion. Liver transplantation did not affect the overall elimination of drug in urine. However, the impaired liver function following transplantation resulted in reduced conversion of MPHS to its active form (MP).

High-performance liquid chromatography separation and quantitation of methylprednisolone from rat brain.

A sensitive, reliable method for the extraction, separation, and quantitation of methylprednisolone from rat brain is reported. The method can accurately quantitate methylprednisolone levels between 9.8 and 2500 ng/injection using a two-step HPLC separation and monitoring absorbance at 254 nm. A 90% extraction recovery of methylprednisolone (interday variation of 9.0% and an intraday variation of 0.0 to 7.7%) from rat cortex was obtained with a double extraction method using low toxicity solvents. These solvents are known to quantitatively extract the neutral lipids and phospholipids from brain. Combined with the ability to separate the neutral lipid and methylprednisolone fractions for further separation, and the ability to separate all phospholipid classes in the first run, this method offers great utility combined with the reliable, high extraction recovery and sensitive quantitation of methylprednisolone.

Pharmacokinetics of methylprednisolone, methylprednisolone sodium succinate, and methylprednisolone acetate in dogs.

The absolute bioavailability and pharmacokinetic parameters of two methylprednisolone formulations (methylprednisolone sodium succinate and methylprednisolone acetate) were determined in five dogs. Plasma concentrations of methylprednisolone, methylprednisolone sodium succinate, and methylprednisolone acetate were measured by sensitive and specific high-performance liquid chromatographic methods. After intravenous methylprednisolone sodium succinate administration, methylprednisolone was released rapidly but the extent of availability was rather low (43.6%). This has been tentatively explained in terms of its subsequent single-pass metabolism in the liver, i.e., hepatic hydrolysis of methylprednisolone sodium succinate followed by immediate hepatic elimination of the released methylprednisolone. After intramuscular administration of methylprednisolone acetate, its absorption was slow (half-time of absorption, 69.04 h) and the availability of the released methylprednisolone was low (42.7%). Therapeutic implications of these results are discussed, especially those which are relevant to shock therapy.

Kinetics of methylprednisolone and its hemisuccinate ester.

Methylprednisolone in the form of its hemisuccinate ester was injected intravenously in doses of 10 mg/kg and 63.1 mg. Plasma levels of methylprednisolone and of the ester were measured and their kinetics were calculated. Results indicate dose dependency in the kinetics of both. About 10% of the dose was excreted unchanged as hemisuccinate in the urine, indicating incomplete conversion of the prodrug. When methylprednisolone (80 mg) was also taken by mouth, the relative bioavailability of the tablets was 99%. Saliva levels of methylprednisolone were low but paralleled plasma levels in the postdistribution phase. No methylprednisolone hemisuccinate was found in saliva.

Strategies in the design of solution-stable, water-soluble prodrugs III: influence of the pro-moiety on the bioconversion of 21-esters of corticosteroids.

Succinate esters and many other carboxylic acid esters utilized as water-soluble prodrugs have limited utility due to their aqueous solution instability. In an earlier study, a strategy for the design of solution-stable 21-carboxylic acid esters of corticosteroids was developed from a consideration of various physical organic factors which influence ester hydrolysis. Several 21-esters of methylprednisolone were synthesized, and their stability in aqueous solution was monitored to demonstrate the feasibility of the approach. In this study, the bioconversion of representative examples of 21-esters of methylprednisolone exhibiting shelf lives of greater than or equal to 2 years at 25 degrees C was monitored to evaluate their utility as prodrugs in comparison to a commercially marketed sodium succinate ester. Ester hydrolysis studies conducted in human and rhesus monkey serum suggest that derivatives having an anionic solubilizing moiety (sulfonate or carboxylate) are not hydrolyzed in serum, while compounds having a cationic (tertiary amino) solubilizing moiety are hydrolyzed rapidly by serum esterases. In vivo pharmacokinetic studies in rhesus monkeys were also conducted to compare the bioconversion rates and overall bioavailability of several solution-stable prodrugs with the 21-succinate ester. Derivatives having solution stability exceeding 2 years at 25 degrees C with a faster bioconversion rate and an overall bioavailability equal to or higher than that of the succinate ester have been identified. Relative bioavailability appears to be highly sensitive to the charge of the solubilizing pro-moiety and pro-moiety chain length.

Effects of steroid treatment on release of cardiac myosin light chain II in acute myocardial infarction in dogs.

The effect of methylprednisolone sodium succinate (MP) on release of myosin light chain II (LCII) from the myocardium was studied in experimental myocardial infarction (MI). Acute MI was produced in conscious, closed-chest dogs by ligating the left anterior descending coronary artery beyond the first diagonal branch. MP, 30 mg/kg, was administered intravenously just before and 24 hours after MI. After MI, LCII levels in the serum were determined serially up to 240 hours. MI size was determined histologically 10 days after MI. In the MP group, LCII levels in the serum within 72 hours were lower than in the control, and cumulative LCII release for 3 days decreased from 530 +/- 159 to 310 +/- 101 ng/ml (mean +/- standard deviation) (p less than 0.001). However, the peak LCII level appeared later (control vs MP, 63 +/- 27 vs 122 +/- 25 hours, p less than 0.001), and the peak LCII level and cumulative LCII release for 10 days were not decreased by MP treatment. MI size also was not reduced by MP (11.0 +/- 4.4% vs 11.8% +/- 4.5% of the left ventricle, difference not significant). Since the rate of disappearance of LCII is rapid and was not affected by MP, these results suggest that MP treatment early after acute MI delays breakdown of myosin filaments, but cannot prevent it.

Uptake and elimination of methylprednisolone from contused cat spinal cord following intravenous injection of the sodium succinate ester.

The uptake and elimination of methylprednisolone by the injured cat lumbar spinal cord were examined following a single 30-mg/kg intravenous bolus injection of the sodium succinate ester. The findings were considerably different from those previously reported for normal lumbar cord. When the glucocorticoid was administered 30 minutes after a 400 gm-cm contusion injury, peak tissue concentrations in both injured and uninjured segments of traumatized spinal cord were not achieved until 30 minutes following drug administration. The elimination of methylprednisolone from injured spinal cord tissue was biphasic in nature, with a rapid elimination phase occurring between 1 and 2 hours after drug administration. This rapid elimination phase was followed by a slower phase which paralleled the constant elimination rate from uninjured tissue of traumatized cord (approximate half-time = 6 hours). Significantly more methylprednisolone accumulated in the injured segment of traumatized spinal cord than in an uninjured segment adjacent to the injury site. This was only true, however, if the drug was administered at times up to 1 hour after injury. If injected after 1 hour, uptake by the injured segment decreased significantly with time after trauma and was no different from that observed for the uninjured segment in the same animal, which showed no significant variation with time after trauma. The probable basis for these differences and the possible clinical implications of these pharmacokinetic characteristics are discussed.

Correlation of methylprednisolone levels in cat spinal cord with its effects on (Na+ + K+)-ATPase, lipid peroxidation, and alpha motor neuron function.

Large intravenous doses of methylprednisolone sodium succinate are associated with biochemical and electrophysiological effects in the cat spinal cord which may be of therapeutic value in the treatment of spinal cord injury. The potentially beneficial effects of large doses of the glucocorticoid include: 1) an enhancement of spinal cord (Na + + K+)-ATPase activity; 2) an attenuation of lipid peroxide formation; 3) a hyperpolarization of motor neuron resting membrane potentials; and 4) an accelerated impulse conduction along the myelinated portion of the motor axon. Each of these is apparent with spinal cord tissue levels of methylprednisolone around 1.3 micrograms/gm wet weight, which are rapidly obtained following a single intravenous dose of 30 mg/kg. The half-life of methylprednisolone in cat spinal cord following a single intravenous administration, as well as the duration of its pharmacological actions, is roughly 3 hours. The data suggest that, in order to be of therapeutic value in the treatment of acute spinal cord trauma, early intervention with high-dose intravenous methylprednisolone (30 to 40 mg/kg) is necessary, followed by intravenous maintenance dosing of 15 to 20 mg/kg every 2 to 3 hours. The rationale and duration for this regimen are discussed.

Placental transfer of methylprednisolone following maternal intravenous administration.

Seven normal patients in labor at term were given 125 mg of methylprednisolone hemisuccinate intravenously shortly before delivery. Analysis of maternal and cord plasma samples indicated that both the hemisuccinate and free alcohol forms of the corticosteroid were transported in pharmacologic levels to the fetal compartment. Since methylprednisolone may have less of an infection-potentiating effect than other commonly used corticosteroids, use of it as a stimulator of fetal lung surfactant deserves further investigation.