An investigation into the loss of preservatives from opthalmic solutions, during filtration sterilization
- Authors: Naidoo, Nadasen T
- Date: 1970
- Subjects: Filters and filtration , Sterilization
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3851 , http://hdl.handle.net/10962/d1012931
- Description: Most eye drops are dispensed in multi-dose containers, hence protection should be given against microbial contamination during use. To remain sterile during it's use, the solution should contain a preservative in such concentration so that it kills micro-organisms in a short time. It has been stated in the literature that the instillation of contaminated eye drops constitutes a greater danger than the intravenous injection of a contaminated solution since the cornea is nonvascular and lacks the normal antimicrobial defences of the blood stream. Amongst the preservatives used, those included in the official formulations for eye drops are Chlorhexidine Acetate, Phenyl Mercuric Nitrate, Benzalkonium Chloride, and to some extent Phenylethanol, which may be used in combination with Benzalkonium Chloride. The main purpose of this investigation has been to determine the adsorption of these preservatives by different filters during sterilization by filtration. Part 1, p. 2.
- Full Text:
- Date Issued: 1970
- Authors: Naidoo, Nadasen T
- Date: 1970
- Subjects: Filters and filtration , Sterilization
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3851 , http://hdl.handle.net/10962/d1012931
- Description: Most eye drops are dispensed in multi-dose containers, hence protection should be given against microbial contamination during use. To remain sterile during it's use, the solution should contain a preservative in such concentration so that it kills micro-organisms in a short time. It has been stated in the literature that the instillation of contaminated eye drops constitutes a greater danger than the intravenous injection of a contaminated solution since the cornea is nonvascular and lacks the normal antimicrobial defences of the blood stream. Amongst the preservatives used, those included in the official formulations for eye drops are Chlorhexidine Acetate, Phenyl Mercuric Nitrate, Benzalkonium Chloride, and to some extent Phenylethanol, which may be used in combination with Benzalkonium Chloride. The main purpose of this investigation has been to determine the adsorption of these preservatives by different filters during sterilization by filtration. Part 1, p. 2.
- Full Text:
- Date Issued: 1970
An investigation of compounds occurring in leonotis species
- Authors: Naidu, Krishna
- Date: 1970
- Subjects: Leonotis -- Analysis , Chemistry -- Analytic , Nuclear magnetic resonance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3852 , http://hdl.handle.net/10962/d1012934
- Description: Two labdane diterpenoids 8-hydroxymarrubiin and leonitin were isolated from Leonotis dysophylla (Benth.) and Leonotis leonitis respectively. Spectral studies of 8-hydroxymarrubiin, C₂₀H₂₈ O₅ʻ showed the presence of a β -substituted furan, a Ϫ-lactone, three tertiary methyl groups and tertiary hydroxyl group (s). The NMR spectrum of 8-hydroxymarrubiin and marrubiin C₂₀H₂₈O₄ʻ were almost identical with the exception of the C₁₇- methyl group which appeared as a singlet in 8-hydroxymarrubiin and as a doublet in marrubiin. The extra oxygen atom was therefore assumed to be present as a hydroxyl group substituted in the C₈₋ position. This was further confirmed by the formation of an epoxide and a Ϫό-dilactone. Leonitin, C₂₀H₂₈O₇ʻ was shown by spectral and chemical evidence to be a diterpenoid dilactone possessing an ester function and an ether linkage. Comparison of the NMR spectra of compound X and leonitin suggested that the acetoxy function occurs in the C₂₀- position. This was further supported by the formation of a 'Ϫό -dilactone. The absence of a β -furan moiety was apparent from chemical and spectral evidence, A structure for leonitin is proposed and aspects of its stereochemistry discussed.
- Full Text:
- Date Issued: 1970
- Authors: Naidu, Krishna
- Date: 1970
- Subjects: Leonotis -- Analysis , Chemistry -- Analytic , Nuclear magnetic resonance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3852 , http://hdl.handle.net/10962/d1012934
- Description: Two labdane diterpenoids 8-hydroxymarrubiin and leonitin were isolated from Leonotis dysophylla (Benth.) and Leonotis leonitis respectively. Spectral studies of 8-hydroxymarrubiin, C₂₀H₂₈ O₅ʻ showed the presence of a β -substituted furan, a Ϫ-lactone, three tertiary methyl groups and tertiary hydroxyl group (s). The NMR spectrum of 8-hydroxymarrubiin and marrubiin C₂₀H₂₈O₄ʻ were almost identical with the exception of the C₁₇- methyl group which appeared as a singlet in 8-hydroxymarrubiin and as a doublet in marrubiin. The extra oxygen atom was therefore assumed to be present as a hydroxyl group substituted in the C₈₋ position. This was further confirmed by the formation of an epoxide and a Ϫό-dilactone. Leonitin, C₂₀H₂₈O₇ʻ was shown by spectral and chemical evidence to be a diterpenoid dilactone possessing an ester function and an ether linkage. Comparison of the NMR spectra of compound X and leonitin suggested that the acetoxy function occurs in the C₂₀- position. This was further supported by the formation of a 'Ϫό -dilactone. The absence of a β -furan moiety was apparent from chemical and spectral evidence, A structure for leonitin is proposed and aspects of its stereochemistry discussed.
- Full Text:
- Date Issued: 1970
- «
- ‹
- 1
- ›
- »