Penicillin absorption

Although the toxicological significance has yet to be studied, age-related differences in the absorption of foreign compounds are demonstrable. Neonatal and geriatric human subjects have low gastric acid secretion, and consequently the absorption of some foreign compounds may be altered. Thus in the neonate, penicillin absorption is enhanced, whereas paracetamol absorption is decreased. 

Tsuji A, Miyamoto E, Hashimoto N, Yamana T. GI absorption of [3-lactam antibiotics II. Deviation from pH-partition hypothesis in penicillin absorption through in situ and in vitro lipoidal barriers. J Pharm Sci 1978 67 1705-1711. 

Huupponen R, Seppala P, lisalo E. Effect of guar gum, a fibre preparation, on digoxin and penicillin absorption in man. Eur J Clin Pharmacol (19S4) 26, 279-81. 

Spectral Characteristics. The iafrared stretching frequency of the penicillin P-lactam carbonyl group normally occurs at relatively high frequencies (1770 1815 cm ) as compared to the absorptions for the secondary amide (1504-1695 cm ) and ester (1720-1780 cm ) carbonyl groups. 

The pharmacology of penicillins differs markedly from compound to compound but has been well reviewed (57). The majority of derivatives, including penicillin G and the antipseudomonal penicillins, ate unstable in gastric acid and ate not available orally. The isoxazolyl penicillins ate relatively acid stable but not consistendy well absorbed by the oral route. Nafcillin and oxacillin ate poody absorbed orally cloxacillin, dicloxacillin, and ducloxacillin ate more teUable. Penicillin V, ampicillin, and patticulady amoxicillin ate relatively well absorbed orally. Esters of ampicillin such as bacampicillin, pivampicillin, and talampicillin improve the level of oral absorption of ampicillin to that achieved by amoxicillin. Absorption can be diminished by food after oral adruinistration, however, and peak blood levels, usually achieved after 1 to 2 h, ate somewhat delayed after ingestion of food. 

The role of IR spectroscopy in the early penicillin structure studies has been described (B-49MI51103) and the results of more recent work have been summarized (B-72MI51101). The most noteworthy aspect of a penicillin IR spectrum is the stretching frequency of the /3-lactam carbonyl, which comes at approximately 1780 cm" This is in contrast to a linear tertiary amide which absorbs at approximately 1650 cm and a /3-lactam which is not fused to another ring (e.g. benzyldethiopenicillin), which absorbs at approximately 1740 cm (the exact absorption frequency will, of course, depend upon the specific compound and technique of spectrum determination). The /3-lactam carbonyl absorptions of penicillin sulfoxides and sulfones occur at approximately 1805 and 1810 cm respectively. The high absorption frequency of the penicillin /3-lactam carbonyl is interpreted in terms of the increased double bond character of that bond as a consequence of decreased amide resonance, as discussed in the X-ray crystallographic section. Other aspects of the penicillin IR spectrum, e.g. the side chain amide absorptions at approximately 1680 and 1510 cm and the carboxylate absorption at approximately 1610 cm are as expected. 

As a class the penicillins do not have a characteristic UV absorption spectrum. UV spectra did, however, play an important role in the structure elucidation of some of the penicillin degradation products during the early structure studies (B-49MI51104). 

One of the most popular orally active penicillins in present clinical use is amoxicillin (12). Its oral effectiveness and broad spectrum of activity against common pathogens as well as its better absorption than its closest precedent competitor, ampicillin (14), largely accounts for this. Higher blood and tissue levels of antibiotics is another means of dealing with resistance. In an attempt to achieve yet further improvements in oral bioavailability and hence blood and ti.ssue levels of amoxicillin, the prodmg fumoxicillin (13) is prepared from amoxicillin (12) by treatment with furfural [3]. The imine moiety is less basic than the primary amine so that the isoelectric point of fumoxicillin is more on the acid side than is that of amoxicillin. 

Ethoxycarbonyloxyethyl 6-(D-a-azidophenylacetamido)penicillinate (98 g) was prepared from sodium 6-(D-a-azidophenylacetamido]penicillinate (397 g, 1 mol), a-chlorodiethylcar-bonate (458 g, 3 mols) and sodium bicarbonate (504 g, 6 molsl. The product showed strong IR absorption at 2090 cm- and 1 780-1750 cm" showing the presence of azido group and /3-lactam and ester carbonyls. 

Paton, Sir William, 2 Penicillin, 149, 150f Perospirone, 163f Pharmaceutics, 1, 169 Pharmacodynamics, 1—2, 163 Pharmacognosy, 1 Phar maco kinetics absorption, 163—164 clinical, 165... 

Penicillin effective aureus -ve -ve aeruginosa Ester absorption... 

Y Yoshimura, N Kakeya. Structure-gastrointestinal absorption relationship of penicillins. Int J Pharm 17 47-57, 1983. 

AE Davis, RC Pirola. Absorption of phenoxymethyl penicillin in patients with steatorrhea. Aust Ann Med 17 63-65, 1968. 

Lennernas, H., Gjellan, K., Hallgren, R., Graffner, C., The influence of caprate on rectal absorption of phenoxymethyl-penicillin experience from an in-vivo perfusion in humans, J. Pharm. Pharmacol. 2002, 54, 499-508. 

The answer is a. (Hardman, pp 1084-1085J Amoxicillin is classified as an aminopenicillin along with ampicillin. Because it is less affected than ampicillin by the presence of food, it has a superior absorption in the GI tract. It is sensitive to penicillinase and has a narrow spectrum of activity toward certain Gram-positive and Gram-negative organisms, but not Pseudomonas. Because it is in the penicillin family, hypersensitivity reactions are a possibility... 

Intramuscular Route. The IM route is frequently used for drugs dissolved in oily vehicles or for those in a microcrystalline formulation that are poorly soluble in water (e.g., procaine or penicillin G). Advantages include rapid absorption (often in under 30 min), the opportunity to inject a relatively large amount of solution, and a reduction in pain and local irritation compared with SC injections. Potential comphcations include infections and nerve damage. The latter usually results from the choice of an incorrect site for injection. 

Figure 22.5 depicts the absorption bands of the sodium salt of Penicillin G at 703 cm F... 

Y. Yoshimura, N. Kakeya, Structure-Gastrointestinal Absorption Relationship of Penicillins , Ini J. Pharm. 1983, 17, 47-57. 

Flucloxacillin is a penicillin that must be taken either an hour before food or on an empty stomach for better absorption. 

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