الفهرس 
MethodologyOnly 14 pages are availabe for public view
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Abstract
Phenytoin (diphenylhydantoin), a hydantoin derivative that has long been known for its use in epilepsy, Clinical data indicate that systemic or topical phenytoin enhances the healing of various types of wounds, chronic ulcers and burns..
The work in this thesis comprises the following chapters:
1- Preformulation studies involve solubility and compatibility study.
2- Formulation and evaluation of phenytoin and its sodium salt in certain topical preparations.
3- Clinical evaluation of selected formulations.
Chapter One
Solubility and Compatibility Study
1- Phase Solubility Studies
The phase solubility of phenytoin in different aquous phosphate buffer (pH6.8) cosolvent systems such as polyethelene glycols (PEG 400, PEG 600 and PEG 6000), propylene glycol (PG), glycerol, ethanol, methanol and isopropanol in concentration range from 0-30% w/w was studied.
The increase in the solubility followed the log-linear model except for the case of glycerol. In the presence of glycerol, the solubility decreased and the minimum solubility was found at around 15%. Few reports on the decrease in the solubility by the addition of organic cosolvents, (the solubility of indomethacin was reported to decrease by the addition of dimethyl acetamide), although clear explanation has never been made on this case, aggregation of the cosolvent molecules may need to be considered, when their amount is not sufficient to provide homogeneous water-cosolvent mixture. The solubilization capacity could be arranged in the decreasing rank order as follow: isopropanol > ethanol > PEGs > methanol > PG.
The phase solubility study applid for phenytoin in different aqueous surfactant systems; Tween 80, Sodium dodecylsulfate (SDS) and Pluronic F127 (PF127) in concentration range (0-8%w/w) was studied.
The results indicated a good linearity between the surfactant concentration and the solubility. The partitioning of phenytoin into aqueous surfactant solutions and hence the solubilization capacity of the tested surfactant towards phenytoin could be arranged in the following decreasing order: SDS > Tween 80 > PF127, which can be attributed to the type and chemical structure of the surfactant.
2- Compatibility Study
The compatibility of phenytoin and its sodium salt with different polymers predicted to be used in formulations, such as PEG 6000, Hydroxypropylmethylcellulose (HPMC) and Hydroxypropylcellulose (HPC) was studied using Differential Scanning Calorimetry (DSC) and Infrared Spectroscopy (IR).
The DSC curves of phenytoin sodium showed a single exothermic peak at about 328.75C0 corresponding to melting of the drug. Such peak doesn’t disappear in the physical mixture. The presences of polymer increases the exothermic characters. This proved that there is no