Suppository base, release from

Te Wierik GH, Eissens AC, Lerk CF. Preparation, characterization, and pharmaceutical application of lineardextrins. III. Drug release from fatty suppository bases containing amylodextrin. Pharm Res 1994 11(1) 108 110. 

Asikoglu M, Ertan G, Cosar G. The release of isoconazole nitrate from different suppository bases in-vitro dissolution, physicochemical and microbiological studies. J Pharm Pharmacol 1995 47(9) 713-716. 

Topical bioavailability can be improved by the enhanced release of a drug from ointment or suppository bases. 

Frijlink, H.W., A.J.M. Schoonen, and C.F. Lerk. 1980. The cyclodextrins on drug release from fatty suppository bases. In-vitro observations, ed. H.W. Frijlink, 77. Groningen Drukkerij van denderen. 

Morgan, D.J., et al. 1992. Prolonged release of morphine alkaloid from a lipophilic suppository base in vitro and in vivo. Int J Clin Pharmacol Ther Toxicol 30 576. 

Polyoxyethylene alkyl ethers have also been used in suppository formulations to increase the drug release from the suppository bases. ... 

El Assasy AH, Foda NH, Badawi SS, Abd-El-Rehim RT. Release characteristics and bioavallability of pirprofen from suppository bases. Egyptian ] Pharm Sci 1995 36(1-6) 15-29. Harmia-Pulkkinen T, Ojantakanen S. In vitro release kinetics of timolol and tlmol oleate from polyethylcyanoacrylate nanoparticles. Part 2. Nanoparticles manufacture with timolol maleate using different surfactants and organic solvents. Acta Pharm Penn 1992 101(2) 57-63. 

Schoonen AJM, Moolenarr F, Huizinga T. Release of drugs from fatty suppository bases I the release mechanism. Int J Pharm 1979 4 141-152. 

Baichwal MR, Lohit TV. Medicament release from fatty suppository bases. / Pharm Pharmacol 1970 22 427-432. 

The influence of the aqueous solubility on in vitro release from fat-based suppositories is shown in Fig. 9.54, the results being collated from the smdy of 35 dmgs grouped into classes 1-V in decreasing order of water solubility. The results maybe explained as follows. The water-soluble active substances will be insoluble in the fatty base, while the less water-soluble material will tend to be soluble... 

Arima, H., Irie, T., Uekama, K. Differences in the enhancing effects of water-soluble P-cyclodextrins on the release of ethyl 4-biphenylyl acetate, an anti-inflammatory agent from an oleaginous suppository base. Int. J. Pharm. 1989, 57, 107-115. 

The release of drug from suppository bases is known to be influenced by various factors such as drug-vehicle interactions, vehicle composition, solubility and particle size of drug in vehicle (18). 

Figure 5 shows the release profiles of FP and its complexes from Witepsol H-15 suppositories. It is evident that the release rate of FP was significantly improved by the inclusion complexations with g-and DM-3-CyDs, while that from TM 3 CyD complex was almost the same as FP alone. The different release behavior between the three complexes may be attributed to the difference in dissolution rate and binding affinity of the complexes to the hydrophobic suppository base. In fact, the release rate of FP from hydrophilic bases such as macrogol suppositories containing the DM-3-CyD and TM-3-CyD complexes, was greater than that from hydrophobic bases such as Witepsol H-15 (11). 

From a biopharmaceutical viewpoint, a large sized suppository may be advantageous. In principal, a larger volume spreads over a larger intestinal surface. As a result more active substance is released from the base, more active substance dissolves in the rectal fluid and the absorption is faster. This is especially important for substances that are poorly soluble in both fat and water, such as paracetamol. The release of active substance from the base in this case strongly depends on the extent of the interface between fat and rectal fluid available for active substance release. From a technological point of view a large size suppository must be... 

Indometacin is often formulated in a macrogol base to get a good biological availability [33]. In that base discoloration and esterification may easily occur. Furthermore, the indometacin slowly crystallises giving the suppository a spotted appearance. The antioxidants butyl hydroxytoluene (BHT), butyl hydroxyanisole (BHA) and disodium edetate are added to improve the stability as well as glycerol to limit crystallisation, for instance in Indocid suppositories (Aspen, UK) [34]. Nevertheless, a fatty base must be preferred. Indometacin is released almost equally from a fatty base as from a macrogol base [8a, 35, 36] and the... 

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