Sildenafil Citrate (API) is more commonly known by its trade name, Viagra. The drug was discovered by Pfizer. It is used to treat penile dysfunction in men. The drug was firstly created in the 1990’s and was to be used as a treatment for high blood pressure, angina and chest pain. During Trials it was discovered that the drug had insignificant effect on angina. In turn an unexpected side-effect was discovered. The drug gave men a penile erection and sustained it for a period of time. The research into heart medicine was stopped while research on penile erection was initiated. Clinical trials were carried out and a great demand was discovered due to the increasing number of men suffering from erectile dysfunction [Potts 2004]. Viagra became the little blue pill that could. The original US patent was issued in October 5th 1993 by the …show more content…
The data obtained showed that the lower hydrated form of sildenafil hemi-citrate is the peak at 5.9° while the higher hydrated form of sildenafil hemi-citrate is the peak 5.5°. Neither of these two peaks is present in the known anhydrous pattern of sildenafil mono-citrate. This is illustrated in figure 2 below. The figure shows the main peaks versus the anhydrous form of sildenafil mono-citrate. The key peaks shown for both the lower and higher hydrate are at approximately 5.9° and 5.5°. This confirms that two separate solid forms exist along with the anhydrous form. The solid formed by drying a higher hydrated form of sildenafil hemi-citrate and by ambient storage after. This is also done for lower hydrated forms of sildenafil hemi-citrate. The difference between these two can be seen in table 2 and table 3 in the appendix along with sildenafil mono-citrate. As seen there are multiple polymorphs of sildenafil citrate [PFIZER