Development and assessment of gastric-retentive sustained release metronidazole microcapsules
- Authors: Makan, Anjana
- Date: 2017
- Subjects: Metronidazole , Drug delivery systems , Helicobacter pylori , High performance liquid chromatography , Gas chromatography , Drugs , Drugs Controlled release
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59240 , vital:27491
- Description: Helicobacter pylori is one of the most common pathogenic bacterial infections and is the leading cause of gastritis, gastroduodenal ulcer disease and gastric cancers. Studies have revealed the prevalence of Helicobacter pylori is high in many countries around the globe. Although Helicobacter pylori is highly sensitive to antimicrobial agents in vitro the clinical eradication rate of the disease is still low. The instability of API at gastric pH, low concentration of API in the gastric mucosa and short gastric residence times are the main reasons for poor eradication rates. The high prevalence rate of this disease necessitates the design and development of gastric-retentive site specific oral dosage forms for the optimized delivery of existing therapeutic molecules and may be an approach to improving the eradication rate of Helicobacter pylori. Metronidazole (MTZ) is a 5-nitroimidazole derivative that exhibits antibiotic and antiprotozoal activity. MTZ is used in combination with other compounds for the treatment of Helicobacter pylori in peptic ulcer disease. MTZ is a potential candidate for inclusion in a sustained release gastric-retentive delivery system that acts in the stomach and since it is unstable in the intestinal/colonic environment enhancing gastric residence time would be a therapeutic advantage. MTZ is a cost-effective therapy that exhibits good anti-microbial activity and has a favourable pharmacokinetic profile. A sustained release gastric-retentive formulation is therefore proposed as an approach to enhance the local delivery of MTZ and improve treatment outcomes for patients infected with Helicobacter pylori. A stability indicating Reversed-Phase High Performance Liquid Chromatography (RP- HPLC) method for the quantitation of MTZ in pharmaceutical dosage forms was developed and optimised using a Central Composite Design (CCD) approach. The RP-HPLC method was found to be linear, accurate, precise, sensitive, selective, and was applied to the analysis of MTZ in commercially available medicines. Preformulation studies were conducted as preparative work prior to manufacture gastric- retentive sustained release MTZ microcapsules. The experiments conducted were tailored for the development of sustained release MTZ microcapsules using a solvent evaporation method. The particle size and shape of the microcapsules was investigated using Scanning Electron Microscopy (SEM). MTZ- excipient compatibility studies were performed using Fourier Transform Infra-red Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD). The results revealed that no definite interaction between MTZ and intended excipients to be used for manufacture of MTZ formulations occurred. A solvent evaporation procedure was used for the manufacture of MTZ microcapsules. Preliminary formulations were manufactured using two different grades of Methocel® at various levels. In addition the impact of processing parameters on performance was also investigated. The formulations were assessed in terms of in vitro release, buoyancy, yield, encapsulation efficiency and microcapsule size. Formulation optimisation was undertaken using a CCD approach and numerical optimisation was used to predict an optimised formulation composition that would produce minimal initial MTZ release, maximum MTZ release at 12 hours and maximum buoyancy, encapsulation efficiency and yield. The kinetics of MTZ release from microcapsules was established by fitting in vitro release data to different mathematical models. Higuchi model and first-order model appeared to best fit the data as majority of the formulation batches had highest R2 values for these models. Short-term stability assessment of the optimised formulation was established by undertaking stability studies at 25°C/60% RH and 40°C/75%RH. No significant changes in any of the CQA were observed over 30 days of stability testing. A gas chromatographic (GC) method was developed and validated for the quantitation of residual acetone and n-hexane. The optimised formulation contained 213.60 ppm/g acetone and 25.23 ppm/g n-hexane which are well below the limits set for residual solvents. In conclusion, gastric-retentive sustained release MTZ microcapsules with potential for further development and optimisation have been successfully developed and assessed in these studies. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2017
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- Date Issued: 2017
Treatment of Parkinson's disease in South Africa and investigation of risk factors causing dyskinesias
- Authors: Gaida, Razia
- Date: 2012
- Subjects: Movement disorders , Parkinson's disease , Drugs
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:10159 , http://hdl.handle.net/10948/d1012466 , Movement disorders , Parkinson's disease , Drugs
- Description: Background: Levodopa is still thought of as the 'gold standard' symptomatic treatment for Parkinson’s disease. However, after four to five years of treatment, levodopa efficacy tends to decline even if there was a good initial therapeutic response. The ideal treatment of Parkinson’s disease is a much debated issue with a range of guidelines available. Objectives: This study was undertaken to analyse medication use and prescribing patterns as well as to determine the risk factors involved in causing dyskinesias in Parkinson’s sufferers. Methods: The study consisted of two parts, namely a drug utilisation review (DUR) and a questionnaire survey. There were 25 523 antiparkinsonian records consisting of 5 168 patients for the year 2010. The questionnaires were verbally administered to patients diagnosed with Parkinson’s disease. A total of 43 patients were interviewed. Results: The average age of the population was 70.74±10.37 years, with the oldest patient being 100 years. Females constituted 59.17percent (5 168: n = 3 058) of the total number of patients. The most common antiparkinsonian products dispensed were combination drugs containing levodopa with a decarboxylase inhibitor and some with a COMT-inhibitor as well (46.5percent; n = 11 875). Males represented 53.49percent (43: n = 23) of the patients included in the questionnaire survey. A review of the medical records showed that patients with dyskinesias were diagnosed with Parkinson’s disease at a younger age and had experienced longer disease duration. Conclusion: Parkinson’s disease is an under-recognised condition in South Africa. Treatment needs to be individualised and based on evidence-based guidelines. Further studies in South Africa, as well as SSA (sub-Saharan Africa), need to be conducted on both the prevalence as well as the treatment of Parkinson’s disease.
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- Date Issued: 2012
Drugs: cures or curse?
- Authors: McCarthy, T J (Terence John)
- Subjects: Drugs , Pharmacy , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/21887 , vital:29798
- Description: With Pharmacy established in our midst at UPE it seems fitting to speak about drugs, since the name pharmacy is derived from pharmakon, the Greek word for drug. The derivation of apteker from the English word apothecary and the German Apotheker is also relevant. Interestingly the Greek root for apothecary means storekeeper, so perhaps things have not changed much in the last few centuries. However, the use of drugs precedes the Greeks, English or Germans by many centuries, and both the Chinese (over 2000 years BC) and the Babylonians (over 4000 years BC) had drug lists or pharmacopoeias. In fact the Babylonians also had a strict medical code and I recall reading that "if the surgeons's knife should slip, the surgeon's hand will be cut off" which seems far better than the modern idea of trying to sue the surgeon after the event, but must have seriously hampered the recruitment of surgeons in those days.
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