The Physico-Chemical and Solvolytic Study of Alprazolam Drug in Ethanol at 303 K

The physico-chemical and solute –solvent interaction of Alprazolam in ethanol were reported at 303 K. The solute solvent interaction have been carriedout by computing various acoustic parameters, Specific acoustic impedance(z),Intermolecular freelength (Lf), Isentropic compressibility (s), Apparent molal adiabatic compressibility (k), Shear’s relaxation (s), and Solvation number (Sn).These parameters have been evaluated by using ultrasound velocity, density and viscosity data.These results are interpreted in terms of solute-solvent interaction between the molecules.


INTRODUCTION
Alprazolam is a triazolobenzodiazepine compound with antianxiety and sedative-hypnotic actions, that is efficacious in the treatment of panic disorders, with or without agoraphobia and in generalized anxiety disorders.It is marketed under the trade name xanax.

EXPERIMENTAL
The solutions were prepared by dissolving the accurately known weight of Alprazolam in ethanol and kept for some time.A continuous interferometer technique was employed for measurement of ultrasound velocity at 2Mhz.The density and viscosity were determined using vibrating densitometer DMA 48 fitted with a Hook G thermostat and viscometer.The experiment were reported atleast twice and results were reproducible with experimental error 0.00002 Kgm 3 and 0.001 cm/ sec respectively.
Computation of different physical parameters: Ultrasound Velocity (V) The variation of velocity with concentration ( C) can be expressed by the following relationship.
The result shows that while the density increases, the isentropic compressibility decreases with increasing concentration of the solute and quantity (dp/dc) is positive while (db s /dc) is negative.
Since the value of are larger than the value of for the system .The concentration derivatives of velocity( dv/dc) is positive.i.e. the ultrasonic velocity increases with increasing the concentration of solute [13][14][15][16] .
Intermolecular free length and isentropic compressibility ( s ) of Alprazolam drug solution decreases with increase in molar concentration of solute (Fig. 1-b) .The complementary use of isentropic compressibility data can provide interesting information of of solute-solvent interaction.
Apparent molal adiabatic compressibility ( k ) varies linearly s the square root of concentration.The value of apparent molal adiabatic compressibilities are negative with the increase in molar concentration.The values of apparent molal adiabatic compressibility as shown in figure 1 (c) .The values of for the solutions of Alprazolam drug were tabulated in table.These results are in agreement with the result reported by Masson 17 for electrolytic solution.
The value of specific acoustic impedance (z) increases with increasing the concentration of Alprazolam drug can be explained on the basis of lyophobic interaction between solute and solvent molecules which increase the intermolecular distance making relatively under gaps between the molecules and becoming the main cause of impedance in the propagation of ultrasound waves are tabulated.
The increase with the concentration suggest a significant interaction between the solute solvent molecules and the values are in agreement with the reported for solution of cobalt carboxylates 18 .
From the above discussion it is concluded that solvolytic study of Alprazolam in ethanol at 303 K shows specific ion -solvent interaction.Alprazolam drug shows significant solvolysis in ethanol.

V=2d×10 5
cm/sec.or V=2d×10 3 m/sec.Density : where 'M': is the weight of the liquid filled in pyknometer used.'r'is radius of capillaries 'h 1 '& 'h 2 'are the heights of the liquid in capillaries Viscosity ( h): where '' is the viscosity of liquid '' is the density of liquid.'' is the time flow of liquid 'a'&'b' are viscometeric constants.Specific Acoustic Impedance Z = Vr.Where, V and 'r' are the ultrasonic velocity and density respectively.Isentropic Compressibility : where 'V' is the ultrasound velocity and '' is the density of liquid mixtures.Intermolecular Free Length: where, 'K' is temperature dependent constant.Molal Adiabatic Compressibility where ' 0 ' and ' s 0 ' are compressibility and density of pure solvent and ' s ' & 'r' are the compressibility and density of the solution respectively.'C' is the concentration in mole/liter of solute.'M' is the molecular weight of solute.Solvation Number : Where ' n 1 ' moles of solvent and ' n 2 ' moles of solute Shear's Relaxation Time () RESULT AND DISCUSSION The ultrasound velocity of the solution of Alprazolam drug in ethanol increases with increasing concentration Alprazolam drug which is shown in above table.