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At least 253 records · Page 14Linked to original sources
PubMed1999

The suppository form of antibiotic administration: pharmacokinetics and clinical application.

The rectal route of antibiotic administration might be used effectively when other routes of administration are inadequate or unsuitable. With the use of various adjuvants, the rectal route can provide satisfactory pharmacokinetics and acceptable local tolerance. Experiments in animals have demonstrated the influence of the pharmaceutical formulation of suppositories on the rectal absorption and systemic distribution of beta-lactams and aminoglycosides. In healthy volunteers and in children under treatment, similar adjuvants--mainly glyceride mixtures or non-ionic surface agents--have increased the rectal absorption of aminopenicillins, cephalosporins and macrolides. Other antibiotics, including metronidazole and cotrimoxazole, have been investigated in respect of their potential rectal administration.

Animals↗
PubMed2006

Reciprocating dialysis tube method: periodic tapping improved in vitro release/dissolution testing of suppositories.

The reciprocating dialysis tube (RDT) method can be used for in vitro release/dissolution testing of suppositories and has been reported to show good in vitro and in vivo correlation. However, for suppositories with viscous excipients, the result remains variable and generally under-predicts in vivo absorption. The purpose of this study was to assess whether periodic tapping of the closure of the RDT could improve in vitro release testing of suppositories. Two commercially available acetaminophen suppositories (A and B) that showed characteristic release behavior under normal rectal temperatures (37 and 38 degrees C) were chosen as test suppositories. In the absence of tapping, suppository A showed different release profiles at 37 and 38 degrees C, but the difference disappeared with periodic tapping. This finding was consistent with minimum temperature effect in the rectal absorption of suppository A in rabbits. Suppository B showed distinct release profiles at 37 and 38 degrees C irrespective of tapping, and the rectal absorption of suppository B in rabbits was affected by temperature. The test variability (CV% and ranges of release values) was substantially reduced in the presence of tapping. In conclusion, the addition of periodic tapping to RDT method developed in this study could improve in vitro release testing of suppositories.

Acetaminophen↗
PubMed1990

Biopharmaceutical evaluation of ketoprofen following intravenous, oral, and rectal administration in dogs.

The influence of the hydrophilicity of three suppository bases on the rectal absorption of ketoprofen was studied. Absorption characteristics of ketoprofen were compared after intravenous, oral, and rectal administrations of 100 mg of drug given in a crossover design to five dogs. Rectal formulations included an aqueous solution and three suppository formulations. After oral dosing, ketoprofen was rapidly absorbed (time of maximum concentration, tmax: 0.83 +/- 0.61 h), and a comparison with the intravenous solution indicated a complete bioavailability of 0.90 +/- 0.10. After rectal administration, the rate of absorption, as evaluated with tmax and mean absorption time, was always slower than after oral dosing. A high variability was observed in the plasma concentrations obtained with suppository formulations; bioavailability values were approximately 20% lower than those from the oral solutions. No statistical difference in bioavailability and peak concentrations between the three suppository formulations was observed. Time of peak concentrations, mean absorption times, and fractions of the dose absorbed 6 h post administration did not show a difference in rate of ketoprofen absorption from the three suppository formulations. This study did not reveal a relationship between rate and extent of ketoprofen rectal absorption and the hydrophilicity of the suppository bases tested.

Administration, Oral↗
PubMed1991

Pharmacokinetics of rectal drug administration, Part II. Clinical applications of peripherally acting drugs, and conclusions.

Part I of this article, which appeared in the previous issue of the Journal, covered general considerations, the physiology of the rectum, spreading of drugs into the colon, rectal absorption, partial avoidance of first-pass elimination, rate-controlled rectal delivery of drugs, irritation of the rectal mucosa and clinical applications of rectal administration, and discussed centrally acting drugs. In Part II, this discussion is extended to drugs which act peripherally and to methods of enhancing rectal drug absorption. The overall summary appeared in Part I.

Administration, Rectal↗
PubMed1988

Pharmacokinetics and clinical efficacy of intrarectal solution of acetaminophen.

Acetaminophen is frequently administered orally to children for its analgesic properties, although its potency has never been clearly evaluated in this population. In certain situations (patients vomiting or unconscious), acetaminophen has to be given rectally. However, the rectal absorption of suppositories is frequently erratic. We undertook this study first, to measure the absorption of an aqueous solution of acetaminophen administered rectally. Secondly, we evaluated acetaminophen's postoperative analgesic effects in children aged 1 to 8 years old undergoing adenoidectomy and/or tonsillectomy and compared its efficacy to meperidine. Twenty children received 20 mg.kg-1 of acetaminophen at the time of induction of anaesthesia while 20 others received 1 mg.kg-1 of meperidine intramuscularly. Thirty-two patients required meperidine in the Recovery Room. There was no statistical difference between the patients who received acetaminophen (18), and those who received meperidine (14). The absorption of acetaminophen was incomplete (peak serum concentration: 70.8 mumol.L-1) and delayed. We conclude that the rectal administration of acetaminophen at the induction of anesthesia results in incomplete and delayed absorption and does not prevent the occurrence of immediate postoperative pain in children undergoing adeno-tonsillectomy.

Acetaminophen↗
PubMedDate not supplied

Absorption kinetics of rectally and orally administered ibuprofen.

The bioavailability of rectally administered sodium ibuprofen solution and aluminum ibuprofen suspension was determined in eight normal subjects relative to the same treatments administered orally. The results indicate that the suspension was less bioavailable than the solution irrespective of the route of administration. Although not bioequivalent, rectally administered ibuprofen solution compared favourably with orally administered ibuprofen solution. The mean AUC and Cmax from rectal administration were 87 per cent and 62 per cent of the corresponding values achieved after oral administration. Mean residence times and peak times were 1-3 h longer with the rectal solution, indicating a slower rate of absorption. Absorption after rectal administration was zero order in some subjects while absorption after oral administration was first order. This may be due to the large differences in surface area between absorption sites. Since sodium ibuprofen solution is absorbed when given rectally, this route of administration could be used in patients unable to take oral ibuprofen.

Administration, Oral↗
PubMed1991

Absorption profiles of rectally administered midazolam estimated by deconvolution.

UNLABELLED: An algebraic deconvolution procedure adopted from the literature has been used to estimate the absorption profiles of rectally administered midazolam (0.3 mg/kg) in 8 healthy subjects. The extent of absorption estimated by the conventional AUC approach has previously been published and was compared to the deconvolution results. In the original study the sampling period was 840 min. When a deconvolution approach is used there may be no need to sample after the absorption is completed. Thus in this communication only samples drawn within the first 120 min and 300 min were used. The bioavailability estimated by the AUC ratio (mean 0.52 +/- SDrel 16%) is compared to the deconvolution results obtained using only data points within 120 (0.46 +/- 22%) (p = 0.02) and 300 min (0.51 +/- 20%) (p = 0.6) after drug administration. The absorption is almost complete after 120 min. Regarding the absorption rates 40% (range 27.55%) of the dose is absorbed after 60 min. The relative (normalised) absorption profiles showed that 79% (range 63-90%) of the maximum absorbed amount is absorbed within 60 min. IN CONCLUSION: Information regarding the rectal absorption of midazolam can be obtained from a sampling period of approximately 5 hours using the deconvolution approach. The algorithm used is relative easy to implement and is very easy to use with polyexponential parameters obtained by curve fitting as input.

Administration, Rectal↗
PubMed1980

The pharmacokinetics and acceptability of benoxaprofen following rectal administration.

The bioavailability of a single 300 mg dose of benoxaprofen was compared after rectal and oral administration in 5 subjects. The total absorption rectally from a suppository was 83% of that achieved orally from a capsule. Six further subjects took a 300 mg benoxaprofen suppository twice daily for 12 d. Steady state plasma levels (mean level 94 microgram/ml) were reached at about 120 h, while the elimination half-life for benoxaprofen was approximately 38 h in this study. The suppositories were well tolerated. The plasma levels obtained compared very favorably with theoretically expected levels and levels obtained after comparable oral doses.

Absorption↗
PubMedDate not supplied

Oral and rectal nalbuphine bioavailability: first-pass metabolism in rats and dogs.

The disposition of the narcotic antagonist/analgesic nalbuphine after i.v., oral, and rectal dosing was evaluated in rats and dogs. In both species nalbuphine had high systemic clearance and low oral bioavailability as a result of extensive first-pass metabolism. Administration to a closed 2 cm length of rectum in rats resulted in complete bioavailability; first-pass metabolism was circumvented. However, the extent of first-pass metabolism increased when the dose was not restricted to the lower rectum. Rectal nalbuphine bioavailability in dogs from a solution or three suppository formulations was low and equivalent to oral bioavailability. This was probably because of upward spreading of the dose and subsequent first-pass metabolism. Sodium salicylate, which has been shown to improve rectal absorption of other drugs, did not affect nalbuphine bioavailability rectally.

Administration, Oral↗
PubMed1998

Studies of drug delivery systems for a therapeutic agent used in osteoporosis. II. Enhanced absorption of elcatonin from nasal mucosa in rabbits.

In this study, the effects of a protease inhibitor, endocytosis inhibitors and an absorption-enhancing agent on the absorption of ((Asu1,7)-eel calcitonin, ECT) from the nasal mucous membrane in rabbits were examined, and the results were compared with those obtained following the rectal absorption of ECT reported in our previous paper. ECT was efficiently absorbed from the nasal mucous membrane and effectively decreased serum calcium (Ca) concentrations. The increase in the area under the percent decrease in serum Ca concentration (deltaCa%)-time curve (deltaCa%-AUC) value, assumed to be an index of the pharmacodynamics (hypocalcemic effect) of ECT, depended on the dose of ECT administered intranasally. When nafamostat mesilate, a protease inhibitor, was coadministered with ECT, the deltaCa%-AUC markedly increased. It is presumed that the influence (enzymatic barrier function) of protease on the nasal absorption of ECT is significant. However, no significant difference in the deltaCa%-AUC value was observed when an endocytosis inhibitor (cytochalasin B or monensin) was coadministered with ECT. ECT administration in combination with sodium decanoate, the sodium salt of a medium-chain fatty acid, effectively increased the deltaCa%-AUC value due to the enhancing effect of sodium decanoate on the nasal absorption of ECT. We conclude that the nasal application offers a promising approach for the administration of pharmaceutical preparations containing ECT with additives such as nafamostat mesilate and sodium decanoate.

Absorption↗
PubMed2006

Synthesis and properties of N-nicotinoyl-2-(5-fluorouracil-1-yl)-D,L-glycine ester as a prodrug of 5-fluorouracil for rectal administration.

N-Nicotinoyl-2-(5-fluorouracil-1-yl)-D,L-glycine (NFG) methyl-(NFGM), ethyl-(NFGE) and isopropyl esters (NFGIp) were synthesized and their potential as a prodrug of 5-fluorouracil (5-FU) for rectal administration was investigated. Chemical conversion proceeded either by elimination of (5-FU) or by hydrolysis of ester group. 5-FU was released from NFGIp, NFGE and NFGM 90.5%, 71.3% and 48.5% of the dose, respectively, in 80% human plasma and 79.8%, 56.3% and 31.6%, respectively, in pH 7.4 buffer solution after 48 h of incubation at 37 degrees C. Release of 5-FU occurred mainly from NFG esters but very slightly from NFG, which suggested that release of 5-FU was greatly dependent on the stability of the ester group against hydrolysis. Solubility (M) in pH 7.4 buffer solution was 0.13, 0.09 and 0.04 and apparent partition coefficient in 1-octanol/pH 7.4 buffer solution was 0.76, 1.61 and 4.2, respectively, for NFGM, NFGE and NFGIp, which were in the ranges suitable for rectal absorption. Plasma concentration (microg/mL) of NFGM, NFGE and NFGIp at 50 min after rectal administration to rats was 1.9, 4.6 and 6.7, respectively, and that for 5-FU was below the limit of detection. Their potential as prodrugs of 5-FU for rectal administration is suggested.

Administration, Rectal↗