Based on the nature of work each header has been subcategorized under the subheading: Preparation and Characterization of the crystal signifiers ; Solubility and Dissolution Studies and Formulation surveies.
8.1 PREFORMULATION STUDIES:
The drug was dissolved in really somewhat soluble in H2O and methyl alcohol, Soluble in 0.1 mol/L HCl, Practically indissoluble in trichloromethane. The runing point of the drug was found to be 185oC
8.2 DETERMINATION OF ? soap OF GATIFLOXACIN:
On the footing of preliminary designation trial it was concluded that the drug complied the preliminary designation. From the scanning of drug, it was concluded that the drug had ?max of 292 nanometers, which was equal to 292 nanometer as reported.
8.3 PREPARATION OF STANDARD CURVE OF GATIFLOXACIN WITH 0.1 N HCL PH 1.2:
From the standard curve of Gatifloxacin ( Table No.6, Graph 1 ) , it was observed that the drug obeys beer ‘s jurisprudence in concentration scope of 1 – 10 µg/ml in 0.1 N HCL pH 1.2. The incline Y = 0.0914x, the correlativity coefficient R2 =0.9999. It follows fit curve since R2 & A ; lt ; 1
8.4 PREPARATION OF CRYSTALS FORMS FROM DIFFERENT SOLVENTS:
Gatifloxacin was obtained as a natural stuff ; it was used as such for the readying of crystal signifiers. The salt showed appreciable solubility merely in methyl alcohol, ethyl alcohol, isopropyl alcohol ( 70 % ) and ethanol: H2O ( 1:1 ) to be used as dissolvers for crystallisation.
8.5 CHARACTERIZATION OF CRYSTALS FORMS:
8.5.1 Optical Microscopy
Photomicrographs showed a distinguishable difference in the morphology of different solid-states crystals signifiers of Gatifloxacin obtained from different dissolvers. The morphology of the crystals obtained may be described as follows:
From GATI – I are Prismatic crystals signifiers ; GATI – II is Spongy opaque like crystal signifiers ; GATI – Three are thin pole like crystal signifiers ; and GATI – Four are Rod shaped like crystal signifiers. It shown in Figure No. 6, 7, 8, 9.
8.5.2 Particle Size Determination
Table No. 8 was shown the atom size distributions of Gatifloxacin crystals obtained from different dissolvers. There is a big difference between the size distributions of these samples. Particle size of GATI – I is 90 ?m, GATI – II is 85 ?m, GATI – III is 94 ?m and GATI – IV is 101 ?m.
8.5.3 Determination of True Density:
Prepared crystals signifiers of GATI – I, GATI – II, GATI – Three and GATI- IV was shown in Table No.8. Obtained crystal signifiers true densenesss were 1.110 g/ml, 1.070 g/ml, 1.125 g/ml, 1.140 g/ml severally. True denseness of all crystal signifiers are more than pure drug true denseness.
8.5.4 FT-IR Spectroscopy
FTIR analysis was carried out to corroborate the pureness and quality of the drug. The consequences of these surveies confirmed the pureness of the drug. On comparing these spectra, differences in the extremum form were observed in the part of 1400cm-1 to 500cm-1.
Infrared ( IR ) spectrometry, another of import technique for word picture of polymorphs, was besides utilised. On comparing the IR spectra of the crystals, differences in the extremum forms were observed for some of the crystal signifiers GATI – I, GATI – II, GATI – Three and GATI -IV to Gatifloxacin between the scopes of 1800-1100 cm-1 ( Fig.7 ) . Forms GATI – II and GATI – Three are somewhat similar in spectra but between the 1800-1100 cm-1 part obtained extremums are different. Extremums at 1719.81 cm-1, 1557.60 cm-1 1395.39 centimeter -1 appeared in signifier GATI – II where as it shifted to 1716.12 cm-1, 1616.58 cm-1, 1391.70 cm-1 severally. Top out at 1321.65 cm-1 appeared in Form GATI – III and 1321.65 cm-1 appeared in Form GATI – II, and disappeared in Form GATI – IV. Peaks at 1391.70 cm-1, 1277.41 cm-1, 1716.12 cm-1 appeared in instance of Form GATI – Three, where as it shifted to 1395.39 cm-1 and 1719.81 cm1 in GATI – IV, and extremum at 1277.41 cm-1 it disappeared in Form GATI – IV. Peak at 1616.58 cm-1 is appeared in GATI – I, where as it shifted to 1557.60 cm-1 in GATI – II. Peak at 1317.95 cm-1 appeared in GATI – I, where as it shifted to 1278.60 and 1277.60 in GATI – Three and GATI – IV severally. Top out at 1240.65 cm-1 appeared in GATI – Four, where as it shifted in all other crystal signifiers. Extremums in pure drug of Gatifloxacin ( GATI – Phosphorus ) are different in all other crystal signifiers as GATI – I, GATI – II, GATI – Three and GATI – Four.
Classs of crystal signifiers of Gatifloxacin characterized on the footing of IR spectrometry and FT-IR Spectra comparing survey and readings of crystals signifiers and pure drug ( GATI – Phosphorus ) was shown in Spectra No. 7 and Table No.9 severally.
8.5.5 Powder X-ray Diffraction Studies ( PXRD )
Sing powder X-ray diffraction ( PXRD ) to be the ideal technique for qualifying polymorphs, all the crystal signifiers were submitted for PXRD surveies. In PXRD ( Fig.6 ) , Form GATI – I and Form GATI – II gave some what similar extremum strengths spectra while remainder of other crystal signifiers ( GATI – III, and GATI – Four ) afforded different forms. Spectra of these signifiers ( GATI-I and GATI – Two ) were neither fiting with one another nor with Form GATI – III nor Form GATI – IV. On this base it was concluded that these crystals existed in three different polymorphous signifiers. It is interesting to observe that the superimposable Form GATI – I and Form GATI – II were prepared from aprotic polar dissolvers while remainders of the other crystals were obtained from polar protic dissolvers.
Gives the PXRD informations obtained for the four crystal signifiers every bit good as the commercial Gatifloxacin in footings of lattice spacing and the comparative strengths. X-ray diffraction forms for all of the three reported polymorphs are given in Figure 6. All the high strength lines ( comparative strength ) observed in the pulverization form of the polymorphs were observed in the pure signifier. High strength line at 19.78o2 theta as appeared in instance of Form GATI – II was absent in staying crystal signifiers every bit good as commercial Gatifloxacin XRD spectrum study. Other signifiers did non demo any intense line in the part 19.78 o2 theta bespeaking Form GATI – Two to be a different polymorph. Form GATI-I showed intense lines which were slightly similar intense lines as Form GATI – Two but o2 theta values different to Form GATI – II. Form GATI – Three showed characteristic intense lines at 9.12, 11.23, 16.70, 19.61o2, 20.94 and 21.69 o2 theta, which were absent in remainder of the signifiers every bit good as commercial Gatifloxacin XRD spectrum study. Form GATI – IV intense extremums at 9.17, 9.83, 12.91, 21.05 and 25.34 o2 theta in instance of absent in staying crystal signifiers but merely one intense extremum ( 9.17 o2 theta ) matched with commercial Gatifloxacin and this type of form was non observed in remainder of the polymorphs.
Above PXRD information was compared with the reported PXRD informations of commercial Gatifloxacin. Commercial Gatifloxacin showed wholly different form every bit good as line strengths to prepared crystals. Commercial Gatifloxacin showed 9.20, 12.95, 12.95, 13.49, 19.92, 21.06 and 24.31 o2 theta. Lines were different in other signifiers of polymorphs. So where as polymorphs reported here showed different intense lines in this part, bespeaking them to be different from commercial Gatifloxacin. Powder X-ray Diffraction Studies ( PXRD ) of four crystal signifiers of Gatifloxacin and pure drug was shown in Table No. 10.
8.5.6 Thermal Analysis:
Gatifloxacin crystal signifiers pure drug ( GATI – Phosphorus ) , GATI – I, GATI – II, GATI – Three and GATI – IV DSC thermograms are shown in Figure No ( s ) , 16-20. DSC thermogram of GATI – I, GAT – III shown little difference in endothermal thaw points as crisp extremums at 186.35oC, 186.42oC and heat of merger at 70.48j/g, 65.76j/g severally. GATI – I and GATI – Three decomposes at 318.36oC and 282.38oC severally. Polymorphous signifier GATI – II shown crisp extremums at 183.96oC, heat of merger at 70.67 j/g. In GATI – I and GATI – Two signifiers holding passages at 161.18oC, 160.80oC severally. GATI – II holding low runing point than the pure drug ( GAT I – Phosphorus ) , GATI – I, GATI – Three and GATI – IV. So, Form GATI – II said to be a metastable Form. GATI – I, GATI – II and GATI – Three signifiers are enantiotropic and GATI – Four and Pure Drug ( GATI – Phosphorus ) are monotropic, so GATI- IV was more stable, proofed by Heat of merger regulation of Burger and Ram Berger ‘s regulations. Forms GATI – I, GATI – Three and GATI – Four are holding high runing point and stable than GATI – P ( Pure Drug ) and GATI – II holding low runing point and metastable signifier. Form GATI – Four is more stable than other three signifiers. DSC information of Crystal signifiers and pure drug ( GATI – P ) of Gatifloxacin was shown in Table No. 11.
TGA shown really interesting consequences, signifier of GATI – I weight losingss start from temperature 61.01oC after that upon increasing temperature it losingss weight at 231.82oC and weight losingss 1.88 % , 9.82 % severally. Then weight loss is quickly occurred and concluding residue was obtained 58.54 % . GATI – Two I weight losingss start from temperature 36.78oC after that it losingss weight at 228.54oC and weight losingss 1.69 % , 8.23 % severally. Then weight loss is quickly occurred and concluding residue was obtained 68.11 % . Crystal signifier of GATI – III shown weight losingss from temperature scope of 37.61oC, 69.63oC, 234.29oC and weight losingss 2.29 % , 7.22 % , 9.08 % in orderly in TGA thermogram, and residue was obtained 63.30 % . GATI – IV signifier weight losingss from temperature scope of 34.32oC and so 253.17oC. Percentage weight losingss as 1.99 % and 9.58 % severally. Final residue was obtained 56.67 % . Pure drug ( GATI – Phosphorus ) weight losingss start from temperature from 39.25oC, 257.28oC and weight losingss 1.88 % 11.76 % severally. Final residue was collected 58.07 % . DTA consequences besides shown impressive consequences and similar to DSC consequences.
8.5.7 SOLUBILITY STUDIES
Solubility of GATI – P ( Gatifloxacin ) was found to be 22.15 mg/ml. Improvement in solubility was observed with crystal signifier of GATI – Two. Where GATI – I, GATI – Three and GATI – IV crystal signifiers solubility lessening somewhat. Solubility of crystal signifiers follows in order of GATI – IV & A ; lt ; GATI – III & A ; lt ; GATI – I & A ; lt ; AGTI – P & A ; lt ; GATI – II. Solubility of crystal signifiers shown in Table No. 12, Graph No. 2.
8.5.8 DISSOLUTION STUDIES
The consequence of the in vitro disintegration survey is shown in table IV. The consequences had shown a pronounced difference in their disintegration behaviour of the crystals signifiers of pure drug and pure drug. Results shown that the sum of crystal signifier of GATI – II disintegration rate was well higher than others crystal signifiers. The highest disintegration rate was observed in the crystal signifier of GATI – II 99.47 % than other crystal signifiers GATI – I, GATI – III, GATI – Four and GATI – P ( pure drug ) disintegration rates 93.73 % , 92.70 % , 90.22 % and 95.02 % severally at the terminal of 60 min. per centum drug release follows in order of GATI – IV & A ; lt ; GATI – III & A ; lt ; GATI – I & A ; lt ; GATI – P & A ; lt ; GATI – II. Percentage of drug release of prepared crystals shown in Table No. 13, Graph No.3.
8.6 Evaluation of Tablets:
The prepared crystals signifiers of Gatifloxacin tablets were subjected to preliminary word picture such as hardness, thickness, % weight fluctuation, crumbliness and decomposition. The evaluated parametric quantities are within the acceptable scope for all the preparations of tablets.
There were no pronounced fluctuations in the thickness of tablets within each preparation bespeaking unvarying behaviour of crystal signifiers throughout the compaction procedure.
The hardness of the tablet was found to be in the scope of 4.6 – 5.0kg/cm2.
Crumbliness of all the preparation showed tablets was found to be in the scope of 0.33 – 0.51 % .
No important differences were observed in the weight of single tablets from the mean weight. It had shown that all the preparations fell within the scope of ± 5 % . The mean weight of tablets within each preparation was found to be unvarying. This indicates unvarying feeling of the die pit during tablet compaction procedure.
All prepared crystal signifiers GATI – I, GATI – II, GATI – Three and GATI – IV shown decomposition clip below 8 proceedingss.
In Vitro Drug Release Profile:
The disintegration trial for in vitro drug release of all preparations was carried out by utilizing of USP Type -II ( paddle ) . A revolving at 100 revolutions per minute with phosphate buffer pH – 7.4 disintegration media was used. The survey carried out at 37±0.5 & A ; deg ; drug release as shown in Table No. 15.
The consequences are observed as crystal signifier of Gati – II shown highest disintegration rate 98.28 % than other crystal signifiers GATI – I, GATI – III, GATI – Four and GATI – P ( pure drug ) disintegration rates 92.34 % , 91.01 % , 88.62 % and 93.58 % severally at the terminal of 90 min. But other crystal signifiers as GATI – I, GATI -II and GATI – IV shown slowest disintegration in their tablet drug release with changeless release than pure drug ( GATI – Phosphorus ) and crystal signifier of GATI – II. Prepared crystal signifiers tablets per centum drug release shown in the order of GATI – IV & A ; lt ; GATI – III & A ; lt ; GATI – I & A ; lt ; GATI – P & A ; lt ; GATI – II. Dissolution tare profile of prepare crystals tablets shown in Graph No. 4.