Tobramycin analysis

Table 9.3 Demographic summary of patients in tobramycin analysis by sex.

An alternative method which could be used to establish the fraction of protein that actually reaches the alveoli is the so-called co-aerosohzation. If a protein is aerosolized from a solution that also contains another low molecular weight substance (deposition marker), it can be assumed that the fractions of protein and deposition marker reaching the alveoli will be the same. The deposition marker should be a substance with a known alveolar epithelial membrane passage (e.g. tobramycin or a decapeptide) which does not undergo absorption after oral administration. The fraction of the deposition marker that is deposited in the alveoli can be established from plasma (and urine) measurements of the deposition marker. The maximum fraction of protein that can pass the alveolar membrane whl then be known. The ratio between the deposited fraction and the fraction that has been absorbed into the systemic circulation (as can be estabhshed form plasma or urine analysis) will provide an estimation of the protein passage across the alveolar membrane. 

The tob-Gene Cluster of S. sp. DSM 40477. For the sequence analysis of the tobramycin (tob) gene cluster of S. sp. DSM 40477, a persistent DNA stretch of 43,220 bp was analyzed, encoding 37 ORFs from which 20 genes are potentially attributed to the tofc-cluster. Eleven genes are dedicated properly to encode... 

The correlation coefficients generated for mono-, bi- and triexponential fits obtained by nonlinear regression analyses are summarized in Table 1. Wilson el al. [8] reported that the rate of tobramycin release from Simplex PMMA beads could be fitted to monoexponential and power functions however, they obtained r2 values<0.9 for both fits. Our results show that, although the monoexponential fit is poor, both biexponential and triexponential fits provided r2 values>0.9. Since the biexponential relationship in equation (2) is proposed to fit our physical model, this approach was adopted in analysis of computer fits to release data. The rate constants, a and P, represent an initial, rapid surface release and a prolonged matrix diffusion-controlled release respectively. 

The release of tobramycin sulphate from non-biodegradable, spherical PMMA implants is biphasic and can be described by biexponential linear regression analysis. 

Table 9.16 Results of bootstrap analysis of tobramycin model presented in Eq. (9.14) with questionable observations and influential patients removed.

Further studies by methylation analysis, n.m.r. spectroscopy, circular dichroism, and m.s. on the gentamicins demonstrated the trisaccharide structure 55 for these aminocyclitol antibiotics. The m.s. studies of these compounds as N-acetylated and permethylated derivatives provided the molecular weight and sequential order of the monosaccharide residues. M.s. studies have also been made on these and other aminocyclitol antibiotics (tobramycin and kanamycin) without prior derivatization. ... 

Figure 7.9 Determination of aminoglycosides in bovine milk fortified at 0.06 ixg/kg as their phenylisocyanate derivatives, by LC-MS analysis (a) [gentamicin Cla(PhIC)5H] (b) [gentamicin C2, 2a(PhIC)5H]+ (c) [gentamicin Cl(PhIC)5H]+ (d) [tobramycin(PhIC)5H]+ (e) [neomycin B(PhIC)6H]+.

To simulate what might happen in the gut, tobramycin 50 mg/mL was mixed with sucralfate 500 mg in 40 mL of water at pH 3.5 and allowed to stand for 90 minutes at 25 C. Analysis of the solution showed that the tobramycin concentration fell rapidly and progressively over 90 minutes to about 1%. When the pH of the mixture was then raised to 6.5 to 7 for 90 minutes, there was no change in the concentration of tobramycin, suggesting that the interaction was irreversible. The reason for this change is not known, but the suggestion is that sucralfate forms insoluble chelates with tobramycin. ... 

The renal toxicity of cisplatin is potentiated by aminoglycoside antibacterials such as gentamicin and tobramycin. Extra care is required in patients treated with cisplatin requiring these antibacterials. In one retrospective analysis in patients taking cisplatin, hearing loss was not associated with the concurrent use of ototoxic drugs, including tobramycin. 

Susceptibility factors for the development of ototoxicity in adult patients with cystic fibrosis have been reviewed in a retrospective cohort study in 39 patients, of whom seven had evidence of ototoxicity, four had cochlear toxicity, two had vestibular toxicity and one had evidence of both [8 ]. In a multivariate analysis, ototoxicity was predicted by trough serum concentrations over lOmg/1 for amikacin and over 2 mg/1 for gentamicin and tobramycin (OR=45 95% 0=3.1, 655). 

J. Szunyog, E. Adams, E. Roets and J. Hoogmartens, Analysis of tobramycin by liquid chromatography with pulsed electrochemical detection, 7. Pharm. Biomed. Anal., 2000, 23, 891-896. 

Automated pre-column deiivadzation and h.p.l.c. analyses of aminoglycoside antibiotics have been reported, in an attempt to overcome problems associated with the instability of the derivatives. Reaction of amikacin with o-phthalaldehyde and mercaptoethanol in a borate buffer, reversed-phase separation, and u.v. detection at 340 nm produced two peaks, one from incomplete derivatization. It was claimed that the method was successfully applied to other aminoglycoside antibiotics containing a primary amino-group, i.e. gentamycin, tobramycin and kanamycin. Other workers have reported related derivatization and analysis conditions for tobramycin wherein mainly one peak was observed, though of unknown identify. ... 

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