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Results for “Rectal Absorption”

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At least 37 records · Page 2Linked to original sources

PubMed1993

Rectal absorption of acyclovir in rats and improvement of absorption by triglyceride base.

The rectal absorption of acyclovir has been evaluated after administration of suppositories without absorption enhancers in rats. The disappearance of plasma acyclovir followed biexponential kinetics after i.v. dosing. Rectal administration of a triglyceride (Vosco S-55 and Vosco S-55 + methylcellulose) suppository gave relatively high plasma concentrations and bioavailabilities (95.3 and 83.4%, respectively) compared with Witepsol and macrogol suppositories. However, the in vitro release profiles from suppositories did not accurately reflect plasma concentrations after rectal dosing. Our results suggest that the rectal administration of acyclovir suppositories may be a promising substitute for intravenous infusion, which is at present used for the treatment.

Acyclovir↗

PubMed1983

Involvement of active sodium transport in the rectal absorption of gentamicin sulfate in the presence and absence of absorption-promoting adjuvants.

The involvement of active sodium transport in the rectal absorption of gentamicin sulfate was examined in rats, employing aqueous microenemas of known total ionic strength (mu) in the presence or absence of absorption-promoting adjuvants. Rectal gentamicin bio-availability, which is negligible (1 +/- 1.2%) at an ionic strength of 0.15 without adjuvants, is significantly (p less than 0.01) increased by including adjuvants in the formulation (sodium salicylate, 12 +/- 4.0%; sodium-5-bromosalicylate, 59 +/- 15.1%; disodium ethylene (dinitrilo)tetraacetate, 24 +/- 9.3%). Pretreating the rectal mucosa cells with ouabain, a specific inhibitor of active sodium transport, significantly (p less than 0.01) reduced gentamicin absorption in response to all three adjuvants. In contrast to previous findings with sodium chloride, high ionic strength choline chloride (mu = 1.056) did not promote gentamicin absorption. The data indicate that active sodium transport is an integral component of rectal absorption of water-soluble compounds and may be involved in the mechanism of action of absorption-promoting adjuvants.

Adjuvants, Pharmaceutic↗

PubMed1989

Studies on sustained-release suppositories. II. Evaluation of polymer electrolyte containing acidic groups for prolonged rectal absorption of bacampicillin in rabbits.

Rectal absorption of bacampicillin hydrochloride (BAPC) was found to show the best bioavailability with Witepsol H-15 as suppository base among various Witepsol bases. However, an effective plasma concentration of drug (above 0.5 micrograms/ml) was only maintained for 2 h, so sustained-release suppositories of BAPC were studied. Bacampicillin reacts with acidic polymer electrolytes such as pectic acid (Pc), chondroitin sulfate (Cd) and precipitates as its adduct with the polymer in an aqueous solution. The dissolution rate of BAPC from the adducts in a solution was slower than that of BAPC itself. The absorptions of BAPC from the suppositories containing the adducts were prolonged, but the bioavailabilities were decreased compared to that from the suppository containing BAPC alone. Similar prolonged absorption could be obtained simply by mixing Pc or Cd with BAPC in a base. Further, the absorption rate was found to be controlled by the amount of the polymer addition, and both a high plasma level and excellent bioavailability were obtained. This desirable outcome may be due to the simultaneous occurrence of rapid absorption of BAPC itself and formation of the adducts.

Ampicillin↗

PubMed2005

Evaluation of snail mucin motifs as rectal absorption enhancer for insulin in non-diabetic rat models.

The use of snail mucin motifs as rectal absorption enhancer for insulin has been evaluated. The mucin motifs were extracted from the giant African snail Archachatina marginata by differential precipitation with acetone. The mucin motifs were found to have a molecular weight of 5780 Da and an isoelectric point of 3.4. At the concentrations evaluated, the mucin exhibited rectal absorption enhancing property for the administration of insulin in rats. The % basal blood glucose level of the rats that received the batch of suppositories containing no mucin were consistently above 100% except at the ninetieth minute when it came down slightly to 97.2%. Rats dosed with the batch containing 7%w/w suppositories showed the greatest blood glucose reduction with mean % basal blood glucose concentration of 61.2%. Batches of the suppository containing 5% and 7% mucin showed more marked and consistent lowering in blood glucose concentration than the other batches containing lower amounts of the rectal absorption enhancer. The batch with 7% mucin reduced the basal glucose level to 44% within 2 h of administration of the glycero-gelatin suppository loaded mucin.

Administration, Rectal↗

PubMed1995

Enhancing effect of viscous sodium hyaluronate solution on the rectal absorption of morphine.

The effect of the viscosity of sodium hyaluronate solution on the rectal absorption of morphine was determined in rabbits. Hollow-type suppositories containing 10 mg morphine in viscous sodium hyaluronate solution of various mean molecular weights (MWs) were prepared. Rectal absorption of morphine in the sodium hyaluronate solution (MW 2.1 x 10(6) daltons) was dependent on sodium hyaluronate concentrations in the range of 0.1 to 3% (w/v). Bioavailability after rectal administration of morphine in 0.1% sodium hyaluronate solution is consistent with that of morphine solution in the absence of sodium hyaluronate and the sustained-release plasma profile was observed for morphine in 3% sodium hyaluronate solution. Administration of hollow-type suppositories containing 10 mg morphine in 1% sodium hyaluronate solution resulted in the highest bioavailability of approximately 2-fold that after administration of morphine in physiological saline solution. Five kinds of sodium hyaluronate solution with MWs of 2.4 x 10(5), 1.0 x 10(6), 1.8 x 10(6) and 2.1 x 10(6) daltons and respective viscosities of 70, 3.3 x 10(3), 3.2 x 10(6), 5.1 x 10(3) and 5.7 x 10(3) cP (20 degrees C) were examined. Optimal viscosity of the sodium hyaluronate solution was found to enhance rectal morphine absorption. These results indicate that the selection of relevant viscosity of the sodium hyaluronate solution may contribute to the improvement of bioavailability of morphine on rectal administration.

Administration, Rectal↗

PubMed1990

Duration of absorption-enhancing effect of sodium octanoate, sodium hexanoate or glyceryl-1-monooctanoate on rectal absorption of gentamicin in rabbits.

The duration of the absorption-enhancing effect of sodium octanoate (C8), sodium hexanoate (C6) and glyceryl-l-monooctanoate (MO) on the rectal absorption of gentamicin (GM) using the hollow-type suppository was investigated in rabbits. To evaluate the duration of the absorption-enhancing effect by pretreatment (treatment of absorption enhancer before GM administration), suppository I containing each absorption enhancer in the cavity was administered into the rectum. Then suppository II containing GM in the cavity was administered at predetermined times (0.33, 2, 6 and 24 h) after the administration of suppository I. Plasma GM levels obtained by the pretreatment with absorption enhancer were compared with those obtained by the simultaneous administration of GM with absorption enhancer. The AUC and Cmax of GM significantly decreased with the pretreatment of C8 (6 and 24 h), C6 (2 and 6 h) or MO (6 and 24 h) before rectal GM administration, as compared with the simultaneous administration of GM with C8, C6 or MO. A marked decrease in the absorption-enhancing effect of C8, C6 and MO on rectal GM absorption was observed by the prolongation of the period between the pretreatment of each absorption enhancer and GM administration. The duration of the absorption-enhancing effect of C6 was shorter than that of C8, whereas this duration of MO was similar to that of C8. The effect of these absorption enhancers disappeared 24 h after the pretreatment. These results suggested that the lowering of the membrane transport barrier function recovered about one day after the administration of C8 or MO.

Administration, Rectal↗

PubMed1994

[Enhancement of rectal absorption of rifampicin by sodium para-aminosalicylate dihydrate in human subjects].

The suppositories of rifampicin (RFP) containing sodium para-aminosalicylate dihydrate (PAS-Na) were prepared in order to enhance the rectal absorption of RFP. By the addition of PAS-Na, the in vitro release of RFP from the suppositories was enhanced and the hardness of the suppositories decreased. The rectal absorption of RFP from the suppositories containing no PAS-Na (control suppositories) was significantly lower compared to oral administration of it (26%) in human subjects. When PAS-Na was added to the suppository (300 mg), both the area under the plasma concentration-time curve (AUC) and the maximum plasma concentration (Cmax) increased significantly compared to those of the control suppositories. The rectal absorption of PAS-Na itself from the suppositories seemed to be fast. PAS-Na might increase the absorption of RFP dissolved in the rectal fluid from the suppositories, but not affect the undissolved RFP.

Administration, Oral↗

PubMed1987

Biopharmaceutical characteristics of a suppository base containing poly (oxyethylene)-poly (oxypropylene) copolymer, Unilube. I. Effects of a suppository base containing Unilube 70DP-950B on release and rectal absorption of aminopyrine in rabbit.

The rectal absorption of aminopyrine (AP) from a three-component-system suppository base (TCS), which is a mixture of oleaginous base, water-soluble base and the poly-(oxyethylene) poly-(oxypropylene) block copolymer, Unilube, was investigated. Albino rabbits were used as the animal model. The bioavailability of oleaginous base and water-soluble base (polyethylene glycol 4000) were 44.3% and 82.6%, respectively. The time to reach maximum plasma concentration (Tmax) of the oleaginous and the water-soluble bases were 21.0 +/- 8.2 min and 33.0 +/- 16.4 min, respectively. When TCS was used, its Tmax was 30 min and increasing the amount of Unilube in the base from 5% (w/w) to 20% (w/w) decreased the bioavailability from 100.4% to 47.2%. The softening temperature of TCS was 55-57 degrees C. Collectively, TCS containing 5% of Unilube gave significantly higher bioavailability than the other bases without softening until 57 degrees C. Also, the results of the two different release tests were compared with the results of an animal experiment in this paper.

Animals↗

PubMed1994

Rectal absorption of ozagrel from suppositories in rabbits.

Rectal absorption of ozagrel (a selective thromboxane synthetase inhibitor) from suppositories was studied in rabbits. Two kinds of suppositories were prepared, one was from ozagrel powder (OPS, ozagrel powder suppository), and the other from ozagrel tablet (OTS, ozagrel tablet suppository). Ozagrel from OPS was absorbed quickly with a Tmax value of 26.3 +/- 7.5 min, and the peak plasma level was significantly higher than that involving intravenous infusion or oral dose (50.3 +/- 6.7 vs. 32.8 +/- 5.4 or 9.9 +/- 1.2 micrograms/ml), indicating that OPS may be a useful dosage form rather than injection. OTS was absorbed less rapidly than OPS, but the AUCs of both suppositories were similar. Because OTS was prepared using an ozagrel tablet, it is fairly easy to get an equal content in each suppository. Therefore, OTS is not only an experimentally interesting dosage form, like OPS, but is also a practical preparation for clinical use.

Absorption↗

PubMed1985

Enhanced rectal absorption of sodium ampicillin by N-acyl derivatives of collagen peptide in rabbits and rats.

The promoting effect of N-acyl derivatives of a collagen peptide which was fractionated from the hydrolysates of collagen on the rectal absorption of sodium ampicillin was studied. An increase in the blood level of ampicillin was observed in rabbits and rats following the administration of a sodium ampicillin suppository containing N-octanoyl(C8-CP), decanoyl(C10-CP), dodecanoyl(C12-CP), and stearoyl(C18-CP) derivatives of collagen peptide. The most efficient action was observed in the suppository containing C18-CP. Some factors influencing the promoting effect of the adjuvants on the rectal absorption of sodium ampicillin from solution were also studied in rats using in situ perfusion method and loop method. The promoting effect of the adjuvants on the rectal absorption of sodium ampicillin was markedly increased in the hypertonic solution. The promoting effect was also suppressed by the addition of calcium chloride to the solution administered to the rectal loop or to the perfusate in the in situ perfusion method. These results suggest that the tight junction of the epithelia of the rectum will be markedly influenced by the presence of the adjuvants, especially in the hypertonic solution. The adjuvant interaction with the calcium ions located in the rectal membrane may be involved in the enhanced absorption of sodium ampicillin.

Ampicillin↗

PubMed1990

Effect of beta-cyclodextrin on the in vitro permeation rate and in vivo rectal absorption of acetaminophen hydrogel preparations.

The amounts of beta-cyclodextrin and hydroxyl propyl methyl cellulose (HPMC) affecting the in vitro permeation rate of acetaminophen containing in both aqueous solutions and HPMC hydrogel preparations through the dialyzer tubing and isolated rat rectum were investigated. The partition coefficient of acetaminophen with or without beta-cyclodextrin in water/n-octanol system was also studied. In vivo absorption experiments of these test formulations were carried out by rectal administration in rats. The results indicate that the concentrations of beta-cyclodextrin and HPMC used decreased the amount permeated of acetaminophen from both test formulations. The more the amount of beta-cyclodextrin or HPMC the slower the permeation rate of acetaminophen. The permeation rate of acetaminophen through the dialyzer tubing was higher than that of acetaminophen through the isolated rat rectum. The result also shows beta-cyclodextrin and HPMC markedly reduced the in vivo bioavailability of acetaminophen from both test formulations. The lower partition coefficient and the higher hydrophilic properties of beta-cyclodextrin inclusion complex, and the higher viscosity of HPMC hydrogel matrix might be responsible for decreasing the in vitro permeation rate and depression of in vivo rectal absorption of acetaminophen. The in vitro permeation data was well correlated with in vivo absorption results, suggesting that the in vitro permeation study regardless of the dialyzer tubing method or the isolated rat rectum method might be used to estimate the in vivo rectal absorption of acetaminophen.

Acetaminophen↗

PubMed1983

Enhancement of rectal absorption of insulin using salicylates in dogs.

Sodium salicylate and 5-methoxysalicylate both increased the rectal absorption of insulin in dogs when co-administered with insulin in various formulations. Microenema formulations containing 4% gelatin showed the highest insulin bioavailability of the formulations studied whereas microenemas (without gelatin) and suppository formulations were not as effective in enhancing the rectal absorption of insulin.

Animals↗

PubMed1991

Enhancement by fatty acids of the rectal absorption of propranolol: in vitro evaluation in the rat.

The effects of a series of fatty acids on the rectal absorption of propranolol (PL) were examined in vitro, using macrogol 1500 base and rat rectal tissue. Lauric acid, at a fatty acid: PL molar ratio of 1:1, produced the largest increase in permeation rate (Js), penetration coefficient and partition coefficient of PL. PL flux was increased 2.5-fold in the presence of lauric acid compared to that without the fatty acid. However, the Js value of PL was decreased at increased molar ratios (e.g., 3:1) of lauric acid. The permeation rate of lauric acid across the rectal membrane was much larger than that of PL. Furthermore, the apparent partition coefficient of PL in an n-octanol/buffer system was significantly increased at a 1:1 molar ratio to lauric acid compared with that of PL alone. These results suggest that a complex-mediated mechanism facilitates PL transport, thereby partially contributing to the enhancement of PL rectal absorption. A similar mechanism is applicable to percutaneous drug absorption, as reported previously. Thus, a portion of PL, after first forming a complex with fatty acids, may rapidly permeate across rectal membranes.

Animals↗

PubMed1982

Release and rectal absorption of aminophylline suppositories prepared in a hospital pharmacy.

In vitro release and in vivo rectal absorption of suppositories containing aminophylline and various bases prepared in our hospital pharmacy were investigated. The release tests were conducted using three methods: the cylindrical filter paper method, the Sartorius solubility simulator method and the disintegration test in J.P. IX. In all cases, release from PEG-containing suppositories was better than that from Witepsol-containing products. However, this tendency was not reflected in the blood level of theophylline after rectal absorption of these suppositories.

Absorption↗

PubMed1983

Adjuvant effects of glyceryl esters of acetoacetic acid on rectal absorption of insulin and inulin in rabbits.

The promoting effect of glyceryl esters of acetoacetic acid on the rectal absorption of insulin and inulin was studied. A decrease in the serum glucose level was observed in rabbits following the administration of an insulin suppository containing glyceryl-1,3-diacetoacetate (adjuvant II) or 1,2-isopropylideneglycerine-3-acetoacetate (adjuvant IV). The promoting effects of adjuvants II and IV on the rectal absorption of insulin and inulin were suppressed by the addition of calcium and magnesium to the suppository. This indicates that adjuvant interaction with the calcium and magnesium ion located in the rectal membrane is involved in the enhanced absorption of insulin and inulin. Adjuvant release from the suppository formulation in addition to adjuvant lipid solubility were found to be other important factors for enhanced absorption of insulin and inulin.

Acetoacetates↗

PubMed1995

Promotion of rectal absorption of sodium ampicillin by disodium glycyrrhetinic acid 3 beta-O-monohemiphthalate in rats.

The promotional effect on rectal absorption of sodium ampicillin (ABPC) by the glycyrrhetinic acid derivative disodium glycyrrhetinic acid 3 beta-O-monohemiphthalate (GA MHPh) was studied in rats and compared with those of sodium caprate (CAP) and sodium glycocholate (GLY). Duration of the promotive effect of GA MHPh was also studied. Rectal absorption of ABPC was significantly enhanced by addition of GA MHPh at an optimum concentration of about 1.5%. The plasma maximum concentration of ABPC was 78.71 micrograms/ml 10 min after its rectal administration at 100 mg/kg with 1.5% GA MHPh. The bioavailability of ABPC with and without 1.5% GA MHPh was 82.12% and 3.92%, respectively. Thus, absorption of ABPC in the presence of 1.5% GA MHPh was about 21 times that of ABPC alone. GA MHPh was more effective as an absorption promoter than either CAP or GLY. Its promoting action on the mucosal membrane was apparent immediately, reached a maximum at 5 min and remained for at least 20 min after rectal administration of the solution. It is therefore suggested that GA MHPh is a very useful promoter absorption of the hydrophilic drug ABPC when administered rectally.

Ampicillin↗

PubMed1984

The use of phenothiazines to enhance the rectal absorption of water-soluble compounds.

The ability of phenothiazines to enhance the rectal absorption of sodium cefoxitin and gentamicin sulphate from aqueous formulations was examined in rats. In the absence of absorption-promoting adjuvants, sodium cefoxitin and gentamicin sulphate bioavailabilities from the rectal compartment were less than 5% of the corresponding intravenous administration. In aqueous microenemas containing 20 mg ml-1 phenothiazine, sodium cefoxitin bioavailability increased to 16-62%, while gentamicin sulphate bioavailability increased to 74-146%. The absorption-promoting potential of chlorpromazine and perphenazine was concentration-dependent, with significant increases in gentamicin sulphate absorption occurring with 1 mg ml-1 chlorpromazine or 2.5 mg ml-1 perphenazine. Maximal gentamicin sulphate bioavailability and serum concentrations were achieved with 10 mg ml-1 chlorpromazine or 20 mg ml-1 perphenazine. The findings indicate that the phenothiazines, which are well absorbed rectally, also significantly enhance the rectal absorption of water-soluble, poorly absorbed compounds.

Animals↗

PubMed1986

Influence of salicylate and anaesthesia on the rectal absorption of theophylline in rats.

The effect of sodium salicylate and anaesthesia on the rectal absorption of theophylline was evaluated in rats. Theophylline proved to be slowly but completely absorbed on rectal infusion in conscious rats, compared with intravenous infusion. Pentobarbital anaesthesia did not influence absorption. In contrast to literature data, the results with salicylate showed that rectal absorption of theophylline was not enhanced.

Anesthesia↗