Retention Of Steroids Research Articles

Local retention efficacy of steroid-loaded PLGA microspheres in epidural injection

Long-term effects of epidural steroid injections for pain management require novel drug formulations that increase tissue retention time. Present study aimed to investigate the local retention of steroid-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres in epidural injection using a rabbit model. Twenty rabbits were randomly assigned to a PLGA group (n = 10) and a triamcinolone acetonide (TA) group (n = 10). Each animal was injected with either TA-loaded PLGA microspheres or conventional TA suspension into the lumbar epidural space. The lumbar segments were then harvested from the sacrificed rabbits on day 1, week 1, 2, and 4 after the injection. On day 1, the residual steroid concentration (RSC) was lower in the PLGA group than in the TA group (5.03 ppm vs. 13.01 ppm). However, after a week, more steroids remained in the PLGA group (3.29 ppm vs. 0.58 ppm). After 2 weeks, fewer steroids remained in the PLGA group than in the TA group, although both contained less than 10% of the initial retention dose. This study shows that steroid-loaded PLGA tended to have higher steroid retention in tissue than the steroid itself at the first week after epidural injection. However, most of the steroids disappeared after 2 weeks in both groups.

Quantitative assessment of steroid amount in the tissue after epidural steroid injection: a new rabbit model.

BackgroundTo develop a rabbit epidural steroid injection (ESI) model for analyzing steroid retention in the tissue, and to assess the difference in steroid retention in the model according to the location and time elapsed after ESI.MethodsFluoroscopy-guided ESI was performed using the interlaminar approach between the lowest two lumbar segments in 13 female New Zealand white rabbits. Four rabbits were allocated to each of three different groups according to the time of sacrifice: 3, 7, and 15 days post-ESI; the remaining rabbit was sacrificed immediately post-ESI to obtain baseline data. After sacrifice, two segments were harvested: the lowest two lumbar vertebrae and another two lumbar vertebrae immediately above these. The residual steroid amount (RSA) and residual steroid concentration (RSC) in the collected spinal columns were analyzed. A linear mixed model was used to compare RSAs and RSCs between the injected and adjacent segments, and among the number of days until sacrifice; P < 0.05 was considered statistically significant.ResultsBoth RSA and RSC of the injected segment were significantly higher than those of the adjacent segment (P < 0.001, both). The RSA and RSC significantly decreased over time (P = 0.009 and P = 0.016, respectively).ConclusionsThe developed rabbit ESI model verified that significantly more steroid was retained at the injected segment than at the adjacent segment and the residual steroid decreased over time. This model could be useful not only for comparing current steroid medications, but also for developing new, better steroid formulations.

P-glycoprotein inhibition promotes prednisone retention in human sinonasal polyp explants.

P-glycoprotein (P-gp) is an efflux pump, which is part of the innate chemo-immunity defense system and is overexpressed in chronic rhinosinusitis with nasal polyps (CRSwNP). P-gp is capable of regulating corticosteroid retention and thus P-gp upregulation has been implicated in steroid resistance in several inflammatory disorders. The goal of this study is to determine whether P-gp regulates intracellular steroid retention in CRSwNP. This was a Massachusetts Eye and Ear Infirmary Institutional Review Board (IRB)-approved study in nasal polyp explants. Polyps were exposed to 50 μg/mL of prednisone for 30 minutes with or without the presence of a P-gp inhibitor (Verapamil 12.5 μM or Zosuquidar 0.31 μM) followed by a 40-minute washout period (n = 16 per group). Intracellular steroid retention was determined by quantifying the concentration of both intracytoplasmic and secreted steroid using an enzyme-linked immunosorbent assay (ELISA). Concentrations relative to control were compared using a Student t test. The intracytoplasmic prednisone concentration was significantly greater relative to control following P-gp inhibition with Verapamil (155.28% ± 22.48%, p < 0.05) and Zosuquidar (125.81% ± 12.41%, p < 0.05). Similarly, the amount of prednisone secreted by the explant was significantly reduced at 30 minutes following P-gp inhibition with Zosuquidar (78.64% ± 2.98%, p < 0.05) and 40 minutes following P-gp inhibition with Verapamil (80.56% ± 5.02%, p < 0.05). Inhibition of P-gp enhances the intracellular accumulation of prednisone in nasal polyps. This suggests that P-gp participates in regulation of glucocorticoid retention in sinonasal mucosa. These findings, coupled with the known overexpression of P-gp in CRSwNP, may point to a possible mechanism for steroid resistance in this patient population.

Separation of steroids using temperature-dependent inclusion chromatography

The influence of temperature on retention and separation of estrogens, progesterone derivatives and β-cyclodextrin in reversed-phase high-performance liquid chromatography has been studied. Steroids were detected using direct UV detection at 240 and 280 nm. Detection of β-cyclodextrin was achieved using a post-column indirect photometric method. Chromatographic experiments were performed using an acetonitrile–water mobile phase (30%, v/v) and a wide range of column temperatures from 0 to 80°C with 20°C steps. Linear Van’t Hoff plots were observed for steroids and β-cyclodextrin when an unmodified binary mobile phase was applied. The retention of steroids was strongly influenced by temperature when the mobile phase was modified with β-cyclodextrin at a concentration of 12 m M. Particularly, for 17β-estradiol and 20α-hydroxyprogesterone a strong deviation from the linear Van’t Hoff plots and a remarkable affinity for β-cyclodextrin was observed. Polynomial regression calculations were performed to fit the set of experimental data points. Using third-order polynomial equations, minimum separation factor values ( α min) were calculated for temperatures from −10 to +100°C with 1°C steps. The best chromatographic conditions for separation of multicomponent samples were chosen. A possible retention mechanism for solutes in the presence of macrocyclic additives is discussed. The results presented describe the role of temperature in high-performance liquid chromatography systems in which the mobile phase is modified with an inclusion agent.

Temperature-responsive liquid chromatography. 2. Effects of hydrophobic groups in N-isopropylacrylamide copolymer-modified silica.

We recently reported the new concept of temperature-responsive liquid chromatography using temperature-responsive poly(N-isopropylacrylamide)-modified surfaces as high-performance liquid chromatography media with aqueous mobile phases. Incorporation of hydrophobic sites is an important factor to improve the efficacy (selectivity and retention) of temperature-responsive chromatography. Toward this goal, we have synthesized semitelechelic copolymers of N-isopropylacrylamide (IPAAm) and butyl methacrylate (BMA) having reactive terminal functional groups using telomerization. The lower critical solution temperatures of the copolymers shift to lower temperatures with increasing hydrophobic BMA content in the poly(IPAAm-co-BMA) relative to that of the IPAAm homopolymer. This temperature-responsive semitelechelic copolymer was grafted to the surface of (aminopropyl)silica through the reaction of activated ester-amine coupling. The polymer-modified silica was used as a column packing material. Separation of a mixture of five steroids having various hydrophobicities was investigated. Retention of steroids on poly(IPAAm-co-BMA)-modified columns is increased with an increase in column temperature. The capacity factors for steroids on the copolymer-modified silica beads was much larger than that on homopolymer PIPAAm-modified columns. The capacity factor for testosterone at 50 degrees C was 33.8 for poly(IPAAm-co-BMA) containing 5 mol% BMA, while that for the PIPAAm homopolymer was 15.0 at the same temperature. The influence of column temperature on steroid retention behavior on copolymer-modified stationary phases was significant compared with the case of homopolymer-modified columns. Furthermore, retention times for steroids increased remarkably with increasing BMA composition. The temperature-responsive elution behavior for the steroids was strongly affected by the hydrophobicity of the grafted polymer chains on silica surfaces. Possible protein separation in temperature-responsive liquid chromatography was explored using insulin chains A and B, and beta-endorphin fragment 1-27. On IBc-3.2-modified silica column, these three peptides were successfully separated at 30 degrees C with 0.5 M NaCl aqueous solution (pH 2.1) as mobile phase. The retention times of these peptides were related to the number of hydrophobic amino acid residues in the peptides. In the proposed chromatography system, elution of target substances is controlled only by a small change in column temperature without any further modification of the aqueous mobile phase.

Effect of novel penetration enhancers on the transdermal delivery of hydrocortisone: an in vitro species comparison

Six novel compounds were examined for enhancer activity using occluded hairless mouse skin (HM), hairless rat skin (HR), human cadaver skin (HC) in vitro with hydrocortisone as the model drug. The compounds investigated included: N-dodecyl-2-pyrrolidinone (DPY), N-dodecyl-2-piperidinone (DPI), N-dodecyl- N-(2-methoxyethyl)acetamide (DMEA), N-dodecyl- N-(2-methoxyethyl)isobutyramide (DMEI), N-dodecyldiethanolamine (DDE), 2-(1-nonyl)-1,3-dioxolane (ND), and Azone®. Controls consisted of no enhancer or vehicle treatment. All enhancers were applied at 0.4 M in propylene glycol 1 h prior to skin application of a saturated suspension of hydrocortisone in the same vehicle. Enhancement ratios (ER) were determined for 24 h diffusion cell receptor concentrations (Q 24), permeability coefficients (P), and 24 h full-thickness skin steroid contents. ER for controls was 1.0. N-dodecyl-2-pyrrolidinone (DPY), an Azone® analog, showed the greatest ER values for permeability coefficient (HM: 21.3, HR: 20.7, HC: 8.0) compared to control (ER: 1.0) and Azone® (HM: 18.0, HR: 13.1, HC: 5.5) in all three animal skin models. All six enhancers exhibited poor skin steroid retention (compared to Azone®) in all three skin models.

Modelling and optimization of the separation of steroids eluted with a micellar mobile phase of sodium dodecyl sulphate containing acetonitrile

The equation 1 k′ = c 0 + c 1μ + c 2ϑ + c 3μϑ + c 4ϑ 2 (μ is the surfactant concentration and ϑ is the amount of modifier) proved to be satisfactory in the description of the retention of several steroids (boldenone, dydrogesterone, medroxyprogesterone, methandrostenolone, methyltestosterone, medroxyprogesterone acetate and testosterone) and two diuretics (amiloride and chlorthalidone) when eluted with micellar mobile phases containing sodium dodecyl sulphate (SDS) and acetonitrile. Modelling of the retention and an adequate selection of the experimental design allowed the rapid and reliable optimization of the separation of a mixture of steroids. The retention of steroids was moderately affected by an increase in the concentration of the surfactant. The elution strength of acetonitrile was relatively low and thus, a large amount of the modifier was required to obtain adequate retention times. However, the small variation in the resolution achieved in mobile phases of increasing eluent strength permitted the separation of the low (boldenone, medroxyprogesterone, methyltestosterone, medroxyprogesterone acetate) from the high (progesterone, clostebol acetate and testosterone propionate) retained steroids in the same chromatogram in less than 40 min.

Structure-retention relationships of steroid hormones in reversed-phase liquid chromatography and micellar electrokinetic capillary chromatography

Quantitative structure-retention relationship (QSRR) studies are useful prediction, finding the relevant structural descriptors for analytes and estimating the relative biological activities of a series of analytes. Most of the studies have been conducted by RP-HPLC and a few by micellar electrokinetic capillary chromatography (MECC). The aim of this work was to find structural parameters and characteristics related to the RP retention and electrophoretic migration of steroids in order to predict the retention/migration of steroid hormones on the basis of their molecular structure. Retention data were obtained with an ODS column using as mobile phases aqueous methanol-acetonitrile (mobile phase A) and methanol-tetrahydrofuran (mobile phase B). MECC was conducted with a sodium dodecyl sulfate (SDS)-borate system and with a mixed micellar solution of SDS and sodium cholate. Several topological indices, such as the connectivity indices, X, were used as structural parameters. Steric factors seem to have a great effect on the retention of steroid hormones, especially with the MeCN-containing mobile phase. Retention in mobile phase B could be predicted more accurately. Topological indices can be used in the modelling and prediction of the retention/migration of steroid hormones when the solutes form a congeneric series and stereochemical properties do not govern the separation process.

Intrarectal formalin application, an effective treatment for grade III haemorrhagic radiation proctitis

Haemorrhagic radiation proctitis (HRP) is infrequently seen amongst the patients who are either undergoing or have undergone radiotherapy to the pelvis. We treated 16 documented cases of HRP, who did not respond to conventional steroid retention enemas, with 4% formalin application. It was observed that the rectal bleeding was controlled completely in 81% cases in median follow up of 11 months (range 6–17 months) and diversion colostomy could be avoided in all the cases. The effectiveness of local formalin application in severe HRP is described in this article.

Mucosal uptake and retention of steroids in rat eleum. Possible explanation of topical efficacy in inflammatory bowel diseases (IBD)

Mucosal uptake and retention of steroids in rat eleum. Possible explanation of topical efficacy in inflammatory bowel diseases (IBD)

Comparison of the liquid chromatographic behaviour of selected steroid isomers using different reversed-phase materials and mobile phase compositions

The retention behaviour of steroid isomers in reversed-phase liquid chromatography was studied. Selectivity for the isomers changed as a function of both temperature and mobile-phase composition. In addition, the influence of the stationary phase on steroid retention and selectivity was studied for a number of monomeric and polymeric C 18 columns and β-cyclodextrin columns. The selectivity of a polymeric C 18 phase toward various androstane standards was similar to that for a liquid crystal phase used in supercritical fluid chromatography.

Argon laser treatment of radiation proctitis.

Radiation therapy for malignant gynecologic disease and prostatic cancer has resulted in increased survival and cure rates. This modality has unfortunately produced debilitating radiation proctitis. Recently, five patients were seen with continuous rectal bleeding secondary to radiation disease of the rectum. Four of these patients were women who were being treated for cervical carcinoma and one was a man with prostatic cancer. These patients were refractory to steroid retention enemas, iron therapy, and benproperine enema therapy. Treatment was accomplished using the argon laser with a 300-micron fiber passed via flexible fiberoptic sigmoidoscope. The most proximal areas were treated first. One and a half watts at 0.5 pulses was used. Up to 50 pulses were delivered per therapy session. The fiber was placed in contact with the lesion and circumferentially for 0.5 cm surrounding each suspected area. Bleeding stopped in the four women after two sessions and in the man after four sessions.

Reversed-phase high-performance liquid chromatography of steroid 3-sulfates and the corresponding unconjugated steroids

Simultaneous separation of steroid 3-sulfates and the corresponding free steroids has been accomplished by reversed-phase high-performance liquid chromatography (RP-HPLC). Addition of ammonium sulfate to the aqueous component of the mobile phase results in retention of the steroid sulfates to octadecyl silica packings byan apparent ion-pairing mechanism without affecting the retention of the free steroids. The retention time of steroid sulfates was dependent on the ammonium sulfate concentration in the mobile phase. Biologically important C 19 Δ 5,3β-hydroxy-steroids and corresponding 3-sulfate conjugates or estrogen and estrogen 3-sulfates have been resolved with this RP-HPLC system.

1. Salazopyrin Suppositories in Ulcerative Colitis

Eighteen patients (12 patients with proctitis and 6 with left-sided or total colitis, suffering from exacerbation at the distal portion of the large intestine) were treated with Salazopyrin suppositories. Of 13 patients who had not responded favourably in spite of oral administration of Salazopyrin and/or steroid retention enema, 7 went into remission, 4 were improved and 2 showed no change. Of remaining 5 patients who were treated initially with Salazopyrin suppositories only, 4 went into remission and one showed no change.Side-effects were observed in one case only. Thus, Salazopyrin suppositories are thought to be useful not only in the treatment of proctitis but also in the treatment of left-sided or total colitis having recurrence at the distal portion of the large intestine.

Brain serotonin and estradiol retention in the hypothalamus and pituitary of the rat.

In order to investigate whether the capacity of hypothalamic and anterior pituitary tissue to concentrate and retain estradiol is affected by serotonin (5-HT), 3H-estradiol (3HE2) retention in these structures was measured after 5-HT synthesis inhibition by either parachlorophenylalanine (PCPA) or 6-fluoro-tryptophane (6 FTrp), or after destruction of midbrain raphe nuclei containing 5-HT cell bodies, as well as after administration of the 5-HT precursor 5-hydroxytryptophane (5-HTP). No modification in 3HE2 retention was observed after tryptophane hydroxylase inhibitors of raphe lesions; administration of the precursor only increased the steroid retention at very high, nonphysiological dose levels. It is concluded that the interaction of 5-HT with gonadotropic release cannot be accounted for by a direct effect on specific estrogenic receptors, but occurs at a different level of gonadotropic release regulating structures or directly on LH-RH neurons.

Comparative bio-availability and activity of proprietary topical corticosteroid preparations: vasoconstrictor assays on thirty-one ointments.

Thirty-one proprietary corticosteroid ointments were evaluated for vasoconstriction using an occluded blanching test. The results were expressed as three parameters: (1) area under the blanching curve, (2) summed % total possible score, and (3) square root transformation of sum of scores divided by number of volunteers. Experiments were performed to (a) compare the bio-availability and activity of the ointments, (b) determine the effect of antimicrobial additivies, and (c) assess the retention of steroids in the skin. Scores for the additivie-containing and 'plain' preparations were within 90% except for Locorten-Vioform/Locorten (58%). A steroid reservoir in the skin was demonstrated lasting for 8-14 days. Selected preparations were re-tested by a non-occluded method. The results for the ointments were compared with those previously obtained using the corresponding creams.

Autoradiographic localization of hormone‐concentrating cells in the brain of an amphibian, Xenopus laevis. II. Estradiol

Autoradiographic techniques for light microscopic examination of sex steroid retention were applied to the brains of male and female Xenopus laevis, and anuran amphibian, after 3H-estradiol administration. Estrogen was concentrated by cells in three telencephalic areas (the ventral striatum, the ventral-lateral septum and the amygdala), the anterior preoptic area, the ventral thalamus, the ventral infundibular nucleus, and in the torus semicircularis. The anterior preoptic area and the ventral infundibular nucleus contained the greatest number of labelled cells. The topography of estrogen-concentrating cells was the same in male and female brains. This fact and comparisons of 3H-estradiol with 3H-testosterone retention in Xenopus suggest that the sex steroid itself, and not the genetic sex of Xenopus determines the pattern of uptake by cells in the brain. The distribution of hormone-concentrating cells in Xenopus has many similarities to that found in birds and mammals. Preoptic, hypothalamic (tuberal), limbic forebrain and specific mesencephalic sites in all these forms contain labelled cells following radioactive sex steroid administration. Findings in Xenopus add to the argument for a phylogenetically stable system of hormone-concentrating nerve cells in limbic, hypothalamic and mesencephalic structures.

局所性抗炎症ステロイド9&amp;alpha;-fluoro-11&amp;beta;，17，21-trihydroxy-16&amp;beta;-metylpregna-1，4-diene-3，20-dione-17-benzoate(Betamethasone-17-benzoate，MS-1112)の薬理学的研究(第1報) 抗炎症作用ならびにその他の薬理作用

The anti-inflammatory activity and the other pharmacological properties of MS-1112, a new steroid compound, were examined and compared with other glucocorticoid analogues such as hydrocortisone acetate (Hydr), betamethasone 17-valerate (Val) and dexamethasone (Dexa). Systemically administered MS-1112 and glucocorticoids had a significant effect in inhibiting rat paw edema induced by various phlogistic stimulations and increasing vascular permeabilities and granuloma formation by cotton pellet or granuloma pouch. The order of those inhibiting activity was, in general, Dexa greater than MS-1112 greater than Val greater than Hydr. Concomitantly, Xthymolysis and adrenal weight suppression and reduced rate of body weight gain after multiple systemical administration were also observed. Locally administered MS-1112 caused an inhibiting activity, without systemic side-effects. This activity was approximately 3 to 5 times more potent than that of Dexa in rat carrageenin paw edema and cotton pellet granuloma. MS-1112 was less active than Dexa in glycogen liver deposition activity and in the depression of plasma level of corticosterone but more active than Val and Hydr. In the dose administered, MS-1112 had neither androgenic and anabolic nor estrogenic and anti-estrogenic activity. From this data, it concluded that MS-1112 is a very potent agent applicable regarding permeability and retention of steroids in a local site.

Sex differences in steroid retention and excretion in rats fed cholesterol.

The mechanism by which female rats maintain a higher level of serum cholesterol than males on cholesterol containing diets was studied. Retention of neutral steroids and excretion of bile acids were significantly higher in females than in males. The composition of fecal bile acids was also sex-dependent. Lithocholic and α-muricholic acids were predominant in females and hyodeoxycholic in males. It was concluded that the sex differences in blood cholesterol levels are mainly due to the higher retention rate of neutral steroids by the females and not by their limited capacity to excrete bile acids.

Sex dependency of steroid retention in rat-liver slices incubated with testosterone.

The hepatic retention of steroids which occurs during the incubation of [4‐14C]testosterone with rat liver slices is demonstrated to be a sex‐specific phenomenon. After an incubation time of 30 min, slices from female animals can be shown to have retained significantly more [4‐14C] steroid than slices from male animals. The tissue/medium distribution ratio is 13 for the males and 30 for the females.Δ4‐5α‐Hydrogenase activity of the liver tissue can be regarded as the driving force for the retention of steroids derived from testosterone turnover. Namely, the steroid retention is positively correlated with the testosterone hydrogenation rate. The Δ4‐hydrogenating activity of the female exceeds that of the male by a factor of 1.73; this is the same factor by which the hepatic retention of the female exceeds that of the male.In contrast, there is an inverse correlation between the production rate of hydroxylated C19O2‐metabolites and the extent of retention. When compared to the female animal, slices from the male possess a higher hydroxylating activity accompanied by a much lower retention.The majority of metabolites isolated from tissue have a retention which is proportional to their production rate; however, the proportionality factor varies from metabolite to metabolite. Thus, for each individual metabolite, the slice is able to maintain a specific concentration gradient against the medium. For these metabolites the retention is sex‐specific only in so far as their production rate is sex‐specific.The retention of testosterone and androstenedione is independent of their production rate. They are found in the incubation medium of both sexes, but only in the tissue of males.