Date of Award

2017

Document Type

Thesis

Degree Name

Master of Science (M.S.)

Department

Pharmaceutical and Chemical Sciences

First Advisor

Bhaskara Jasti

First Committee Member

Xiaoling Li

Second Committee Member

Rajendra Tandale

Abstract

Solubility is the amount of solute in the solvent system at phase equilibrium with certain temperature and pressure. Many of the new chemical entities are lipophilic molecules that require techniques to enhance solubility. Solubility enhancement can be achieved by either physical and/or chemical modification of the drug. Various techniques are available for solubility enhancement of poorly soluble drugs include particle size reduction, salt formation, solid dispersions, use of surfactants, prodrug, crystal modification, etc.

In this study, the three model drugs belong to BCS class II and IV having low solubility with a certain range of physicochemical properties were studies in solubility enhancement using fusion method, co-precipitation, nano-milling and spray drying techniques. The two different polymers employed for solubility enhancement are PEG 8000 and PVP 40,000. Solubility was determined by Shake Flask method at the temperature of 37±0.1 °C. The objective is to investigate the enhancement of solubility of the three model drugs namely Glipizide, Carvedilol and Furosemide in 1:1, 1:5 and 1:10 drug-polymer ratios and are characterized by Differential Scanning Calorimetry (DSC).

The Solubility of Glipizide was enhanced from 11.18 ± 1.78 µg/ml to 35.73 ± 0.04 µg/ml by 219 % increase with nano-milling technique at 1:5 ratio with PEG 8000 as carrier whereas with PVP 40000 as carrier, 286 % increase in solubility to 43.26 ± 7.87 µg/ml was observed at 1:1 ratio by fusion method. The solubility of Carvedilol was enhanced from 5.04 ± 0.55 µg/ml to 17.51 ± 0.94 µg/ml by 246 % at 1:5 ratio by fusion method with PEG8000 as carrier and 2924 % enhancement in solubility to 152.70 ± 9.09 µg/ml at 1:10 ratio by nano-milling with PVP40000 as the carrier. Furosemide showed an increase in solubility from 55.94 ± 2.48 µg/ml to 164.11 ± 9.18 µg/ml by 193 % at 1:10 ratio by nano-milling technique with PEG8000 as carrier whereas with PVP40000 as carrier, 444 % increase was observed at 1:1 ratio by nano-milling technique with solubility of 304.52 ± 23.11 µg/ml. The data showed that the decrease in percentage crystallinity and enthalpy of fusion of the model drugs upon implementing solubility enhancement techniques with the effect of particle size and the carrier used resulted in the increase of aqueous solubility of the model drugs.

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