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At least 73 records · Page 4Linked to original sources
PubMed1982

Effect of salicylate on the rectal absorption of lidocaine, levodopa, and cefmetazole in rats.

Salicylic acid and sodium salicylate have been found to enhance the absorption of lidocaine, levodopa, and cefmetazole after rectal administration to rats. These drugs represent a base (lidocaine), an acid (cefmetazole), and a substance (levodopa) which exists as a zwitterion in solution. The rectal absorption of each type of drug, as well as theophylline, a neutral compound, was enhanced by salicylate, particularly at pH values where the substances exist primarily in their ionic form. A requirement for the observed enhancement is that salicylate be present in the rectal membrane. The loss of drug from the perfusing solution was greater from solutions having an ionic strength of 0.75 than from those with mu = 0.15.

Animals↗
PubMed1982

Rectal absorption and disposition of secobarbital in epileptic children.

The absorption and disposition of rectally administered secobarbital was studied in ten epileptic children, ages 2-13 yrs. Five subjects received secobarbital rectally in solution, and the other five received secobarbital suppositories. Concentration of secobarbital in serum was serially determined during 48 hrs after a single rectal dose of about 5 mg/kg. The rate of absorption of secobarbital, as measured by the time to reach peak serum concentration, was much more rapid from the solution than the suppository (0.92 +/- 0.47 hr vs 4.60 +/ 2.30 hr). The peak serum concentration of secobarbital in the solution group was consistently higher than in the suppository group (2.26 +/- 0.37 micrograms/ml vs 1.35 +/- 0.24 microgram/ml). None of the individual peak serum concentrations exceeded 3 micrograms/ml, which is well below the previously reported minimum toxic concentration of secobarbital (ie, 6 microgram/ml). The elimination half-life of secobarbital varied over a wide range, from 2.7 to 13.5 hr, and is, on the average, shorter than estimates previously reported for adult volunteers or poly-drug abusers. Also, the mean elimination half-life did not differ between the solution and the suppository groups. The extent of rectal absorption of secobarbital, as assessed by the area under the serum concentration time curve, was not significantly different between the solution and the suppository treatments. If rectal secobarbital is considered for treatment of prolonged seizure, a rectal solution may offer a more rapid and consistent onset of action than with the suppository preparation.

Adolescent↗
PubMed1989

Rate-controlled rectal absorption enhancement of cefoxitin by co-administration of sodium salicylate or sodium octanoate in healthy volunteers.

1. The effects of sodium octanoate and sodium salicylate on the rectal absorption of cefoxitin were investigated in healthy volunteers. Drug solutions were given either as a bolus or as a zero-order infusion. 2. On rectal infusion sodium octanoate and sodium salicylate both enhanced mean cefoxitin bioavailability (+/- s.d.) from 5.0 +/- 1.2% to 9.1 +/- 1.3% and 9.2 +/- 1.5%, respectively. After rectal bolus delivery octanoate increased the mean cefoxitin bioavailability from 7 +/- 3% to 17 +/- 3%, whereas bolus salicylate did not produce a statistically significant effect. All formulations were well tolerated by the volunteers. 3. It is concluded that both octanoate and salicylate are capable of enhancing rectal cefoxitin absorption in man; rate of delivery seems to be an important factor.

Absorption↗
PubMed1988

Effect of medium chain glycerides on enteral and rectal absorption of beta-lactam and aminoglycoside antibiotics.

The rat enteral and rabbit rectal models were utilized to study the effect of Capmul (medium chain glycerides) on the absorption of a selection of beta-lactam and aminoglycoside antibiotics. All tested non-orally available beta-lactam antibiotics (cefamandole, cefotaxime, moxalactam, cefoxitin, mezlocillin, carumonam, penicillin G and amdinocillin) showed increased absorption enterally in rats and rectally in rabbits when formulated with Capmul. The orally available beta-lactam antibiotics, cephalexin and cephradine, were not enhanced in their enteral or rectal absorption by Capmul in the two model systems. Ampicillin absorption was enhanced rectally and enterally by Capmul. Rectal absorption of the aminoglycoside antibiotics, tobramycin and gentamycin, was enhanced by Capmul while enteral absorption was not.

Aminoglycosides↗
PubMed1991

Enhanced rectal absorption of insulin in rabbits from hollow-type suppositories containing insulin and glyceryl-1-monooctanoate.

The absorption of two kinds of insulin (from porcine or bovine pancreas) from the rectum of rabbits after the administration of hollow-type suppositories containing insulin and glyceryl-1-monooctanoate (GMO) as an absorption-enhancing agent was investigated. Two types of suppositories were employed: type I containing insulin in an aqueous solution (approx. 25 IU/mg/100 microliters citric buffer solution at pH 3.0) in the cavity of the suppository and GMO mixed with a base material (Witepsol H-15), and type II containing insulin in a crystalline form in the same amount as in type I. Without GMO, the insulin and glucose levels in plasma were unchanged, whereas a marked increase in the plasma levels of insulin and a decrease of glucose concentrations were found following coadministration of insulin and GMO by the type I suppository. Similar enhancement of rectal absorption of insulin was obtained from porcine and bovine sources. In the case of the crystalline insulin, despite the use of the same amount of GMO, porcine insulin was more efficiently absorbed than bovine insulin by the type II suppository. GMO enhances the absorption of insulin in an aqueous solution or a crystalline form, and the dissolution rate of insulin may be an important factor in the rectal absorption of insulin.

Administration, Rectal↗
PubMed1989

Enhancing effect of glyceryl-1-monooctanoate on the rectal absorption of gentamicin from hollow-type suppositories in rabbits.

A hollow-type suppository containing gentamicin (GM) in its cavity was prepared using Witepsol H-15 (H-15) mixed with glyceryl-1-monooctanoate (MO) or MO alone in the body of the suppository (type I) and a suppository (type II) containing GM and MO in the cavity was constructed using H-15 in the body of the suppository. Without MO, GM (60 mg) was not absorbed (plasma GM levels less than 1 microgram/ml). However, the absorption of GM from the rectum of rabbits was enhanced by coadministered MO in types I and II. Even when the amount of GM was decreased to 6 mg (1/10), GM was observed in the plasma (Cmax, 3.5 +/- 0.3 micrograms/ml) after administration of the suppository made from MO mixed with H-15. The enhancing effect of MO on the rectal absorption of GM could not be further increased by incorporating an amount of MO larger than approximately 300 mg into the suppository. This study demonstrates that MO can be used in the two types of hollow suppositories as an effective enhancing agent of rectal absorption of poorly absorbed drugs such as GM.

Animals↗
PubMed1984

Improvement of bioavailability of poorly absorbed drugs. I. Effect of medium chain glyceride base on the rectal absorption of cefmetazole sodium in rats.

The effect of medium chain glyceride on the rectal absorption of cefmetazole sodium is investigated using an in situ experiment in rats. Each glyceride component of medium chain glyceride was separated using a high-performance liquid chromatographic method. The promoting effect of medium chain glyceride was found to be mainly due to glycerylmonocaprylate and dependent on the concentration of glycerylmonocaprylate. When cefmetazole sodium in medium chain glyceride solution was administered into the rectal lumen of rats, rapid absorption of the drug was observed leading to a residual amount of about 45% at 15 min after administration. The promoting effect of medium chain glyceride was found to be more effective in the rectum than in the small intestine.

Animals↗
PubMed1994

Enhanced rectal absorption of itazigrel formulated with polysorbate 80 micelle vehicle in rat: role of co-administered esterase.

We investigated the effect of esterase on rectal absorption in the rat of itazigrel using polysorbate 80 (PS-80) micelle as a vehicle to overcome the poor aqueous solubility of itazigrel. The itazigrel formulation prepared with PS-80 increased the absorption compared with a 0.25% carmellose sodium suspension, probably by supplying the itazigrel solute to keep a high concentration at the epithelial surface. When esterase was co-administered with the formulations containing PS-80, the absorption of itazigrel from rat rectum was accelerated further, by rapid release of itazigrel from the micelle vehicle after enzymatic degradation of the PS-80 micelle.

Absorption↗
PubMed1997

[Pharmacokinetics of rectal absorption of amodiaquine in rabbits].

Experimental investigations were made in rabbits to examine the rectal absorption of antimalarial amodiaquine [AQ]. To calculate the pharmacokinetic parameters AQ was administered orally (20 mg/kg) and rectally (20 mg/kg) to the animals and the blood concentrations of the drug were controlled during a time interval of 120 hours with help of spectrofluorometric method. The pharmacokinetic analysis was performed by use of two-compartment open model system. Time-concentration curves were fitted to the data in experiments by computer program (MEDUSA) and the kinetic parameters were given in the Tables 1. and 2. It was established that rectally administered AQ resorbed not only from solution but from suppository, too. The bioavailability of the rectal preparations relating to the oral dosage form was 63.35% and 68.70%, respectively. The most appropriate drug delivery system for rectal application had been selected previously.

Administration, Oral↗
PubMed1982

Enhanced rectal absorption of theophylline, lidocaine, cefmetazole, and levodopa by several adjuvants.

Ten potential adjuvants for rectal absorption which are structurally similar to salicylate have been examined using an in situ perfusion of the rat rectum technique as well as an in vivo absorption method from microenemas. All of the adjuvants studied readily disappeared from the perfusate at pH 4.5; however, several were not absorbed well at pH 7.4. Only those that were lost rapidly from the perfusate at pH 7.4 were effective in enhancing the disappearance of the drugs (theophylline, lidocaine, cefmetazole, and levodopa) at either a pH of 4.5 or 7.4. The compounds that were effective in promoting the disappearance of drugs from the rectal perfusate all had hydroxy and carboxy groups. Those substances lacking a hydroxy group were not effective. The binding of these potential adjuvants and salicylates to rat rectum tissue was studied by equilibrium dialysis. Those adjuvants with relatively high binding to rat rectal tissue were better absorbed themselves and promoted the disappearance of drugs more than those substances exhibiting little binding. Thus, adjuvant binding to some feature of the rectal membrane appears to be important in the enhanced absorption of drugs from the rectum under the conditions of this study.

Adjuvants, Pharmaceutic↗
PubMed2003

Preparation and rectal absorption of highly concentrated glycyrrhizin solution.

We developed a simple method for preparing a highly concentrated solution of glycyrrhizin monoammonium salt (GZ) at low viscosity with no surfactants nor organic solvents and investigated the absorption profile after rectal administration to rats. GZ (200 mg/ml) was dissolved in phosphate buffered solution, pH 7.0; over 350 mM concentration was maintained for the aqueous solution without gel-formation. When glycerin was used as a non-aqueous formulation, GZ did not form gel. Apparent permeability coefficients of GZ obtained from 350 mM phosphate buffered solution (pH 7.0) and glycerin solution through rat rectal mucosa estimated by in vitro parallel diffusion chamber technique were 0.686 x 10(-6) and 0.379 x 10(-6) cm/s, respectively. On the other hand, the area under plasma concentration-time curves of GZ in 400 mM phosphate buffer (pH 7.0) and glycerin formulations after rectal administration to the rat were significantly higher than that in polyethylene glycol 400/propylene glycol (55 : 5) formulation. Maximum plasma concentrations of these formulations were dependent on the apparent permeability coefficients of GZ. Increased absorption observed by phosphate buffered formulation accompanied no pronounced histological damage in mucosa. These results demonstrate that addition of a highly concentrated phosphate salts is effective not only for lowering the viscosity of a highly concentration of GZ solution, but also for improving the mucosal GZ absorption.

Administration, Rectal↗
PubMed1980

Oral and rectal absorption of chloral hydrate and its betaine complex.

Chloral hydrate and its betaine complex was administered orally and rectally to nine healthy male subjects. The urinary excretion, which was a reflection of absorption, of a metabolite, trichloroacetic acid, was determined. No statistically significant difference was found between the oral absorption of chloral hydrate and its betaine complex and between the rectal absorption of chloral hydrate and its betaine complex. A statistical difference was found between the oral and rectal absorption of chloral hydrate and between the oral and rectal absorption of chloral betaine.

Administration, Oral↗
PubMed1989

Rectal absorption of E-2078 (dynorphin analogue peptide) in rats.

The plasma levels in rats of a dynorphin analogue peptide (E-2078) after rectal administration have been studied. The bioavailabilities of E-2078 after rectal administration, subcutaneous injection, intramuscular injection, and oral administration were 21.6, 67.8, 67.1, 0.7%, respectively. The effect of dose, pH, osmolarity and viscosity on the rectal absorption of E-2078 were studied. A sigmoid relationship between the dose and the AUC was observed on rectal administration, while there was a linear relationship on intramuscular administration. The AUC was increased in acidic solution and highly viscous solution. The osmolarity did not affect the absorption of E-2078. In microscopic studies, E-2078 caused little or no damage to the rectal mucosa in rats.

Administration, Oral↗
PubMed1987

Enhancement of the rectal absorption of sodium ampicillin by N-acylamino acids in rats.

The promoting efficacies of N-acyl derivatives of amino acids on the rectal absorption of sodium ampicillin were investigated using the rat rectal loop technique. N-Acyl derivatives with longer carbon chains in the acyl moiety showed a greater promoting potency. The promoting potencies of N-acyl derivatives of phenylglycine and phenylalanine were greater than those of glycine and alanine derivatives when compared at the same length of carbon chain in their acyl moieties. The promoting action of N-acylamino acids was not influenced by the presence of N-ethylmaleimide or ouabain. The promoting potencies of N-acylamino acids were depressed in the presence of calcium chloride in the rectal loop. The contribution of the calcium ion sequestration capacity of N-acylamino acids to their promoting efficacies is discussed.

Amino Acids↗
PubMed1998

Enhanced rectal absorption of amphotericin B lyophilized with glycyrrhizinate in rabbits.

The influence of bases and additives in the formulation for rectal absorption of amphotericin B (AMB) lyophilized with dipotassium glycyrrhizinate (GLYK) was investigated using rabbits in relation to an in vitro release test. The release of AMB from the fatty base of Witepsol or a medium chain triglyceride (MCT) was markedly faster than that from the hydrophilic base of macrogol. The addition of polyoxyethylene (2) lauryl ether (POE(2)LE) into the fatty bases led to a marked increase in the release rate, whereas POE(9)LE or sodium lauryl sulfate resulted in a significantly lower release rate. Animals received rectally each of seven AMB formulations of Witepsol H-15, macrogol, MCT with surfactants and aqueous solution. The absorption of the AMB lyophilized mixture with GLYK at a 1:9 molar ratio from a MCT base was significantly superior to that from macrogol. The addition of POE(2)LE into the MCT base resulted in a marked increase in bioavailability, showing the highest bioavailability of 4.9%. High serum levels of over 100 ng/ml of serum were maintained for 24 h following administration. The lowest bioavailability was 0.32% for the macrogol suppository. There was a good correlation between the release rate of AMB from the formulations and bioavailability. These results suggest that an AMB rectal formulation may provide a promising therapeutic alternative to infusion, taking into account the serum level of AMB exceeding the minimal inhibitory concentration of the infecting organism.

Absorption↗