INTRODUCTION:

Spherical agglomerations are often defined as “a novel particle engineering techniques by which agglomeration are often administered simultaneously in one step to rework crystals directly into compacted spherical form. ^1-3. besides producing spherical crystals it also enables co-precipitation of medicine and encapsulating polymers within the sort of spherical particles. This system also can be exploited to extend solubility, dissolution and hence bioavailability of poorly soluble drugs^4,5. The 2 most ordinarily used techniques of spherical agglomeration are wet spherical agglomeration method (WSA), quasi-emulsion solvent diffusion method (QESD, Transient emulsion)^6,7.

But there are two extensions of those techniques, ammonia diffusion system (ADS) and crystal-co-agglomeration technique (CCA). Another technique of this process is Neutralization, where first fine crystals form by neutralization then it'll agglomerate with the assistance of a bridging liquid. CCA may be a novel technique developed to beat the restrictions of spherical crystallization. it's a modification of the spherical crystallization technique and used for size enlargement of all, low dose, high dose, poorly compressible drugs and combination of medicine with or without diluents. during this technique drug is directly crystallized and agglomerated together with an excipient or with another drug with help of bridging liquid. Excipient or drug may or might not be crystallized during this system. An excipient which is employed during this technique should have affinity toward the bridging liquid^8,9.

Thiocolchicoside is N - [3 - (β - D - glucopyranosyloxy) - 1, 2 - dimethoxy - 10 (methylthio) - 9 – oxo - 5, 6, 7, 9 - tetrahydrobenzo [a] heptalen-7-yl] acetamide. Thiocolchicoside (THC) is a semi-synthetic derivative of colchicines; it has an affinity for the inhibitory Glycine and gamma-aminobutyric acid (GABA)-A receptors. It is used in the treatment of rheumatologic, traumatic and orthopedic disorders. THC is used as muscle relaxant agent without any side effects, its safety and efficacy is demonstrated in many clinical trials.

Famotidine is histamine H2-receptor antagonist. It is widely prescribed in gastric ulcers, duodenal ulcers, Zollinger-Ellision syndrome and gastro esophageal reflux disease. In the management of benign gastric and duodenal ulceration the dose is 40mg daily by mouth at bed time, for 4 to 8 weeks. In gastro esophageal reflux disease the recommended dose is 20mg by mouth twice a daily for 6 to 12 weeks, where gastro esophageal reflux disease is associated with esophageal ulceration; the recommended dose is 40mg twice daily for similar period¹¹.

MATERIALS AND METHOD:

Thiocolchicoside and Famotidine were procured from Yarrow chem., Mumbai, Hydroxypropyl Methylcellulose (HPMC) K15M was obtained as a gift sample from Colorcon, Goa, and Poly Vinyl Alcohol (PVA) was procured from S.D. Fine Chem, Mumbai. All other chemicals and reagents used were of analytical grade.

Drug-Excipient Interaction Study:

The possible chemical and physical interaction between the drug and polymers was carried out by Fourier transformation infra-red spectroscopy (FT-IR). The FTIR spectroscopy was employed to further characterize the possible interaction between drug and excipients in the solid state on an Infrared spectrophotometer (Shimadzu Affinity-l) by conventional KBr plate method. 1:1 of drug sample was mixed with powdered potassium bromide. The mixture was passed with 25.000psi pressure in a press to form a small pellet. IR spectrum of drug was recorded in the frequency range 400-4000cm^-1. The significant peaks were recorded and were matched with standard FTIR¹².

Standard Calibration Curve of Zolmitriptan Hydrochloride:

A UV absorption maximum was determined by scanning 10µg/ml solution of Thiocolchicoside and Famotidine in phosphate buffer of pH 6.8, by using UV-visible spectrophotometer. Further a representative spectrum was drawn of Thiocolchicoside in phosphate buffer of pH 6.8 at 272nm and spectrum of Famotidine was drawn in phosphate buffer of pH 6.8 at 421nm¹².

Preparation of Crystal Co-agglomerates:

Thiocolchicoside and Famotidine agglomerates were prepared using a three solvent system comprising methanol as a good solvent dichloromethane as a bridging liquid and water as a bad solvent. In a vessel, PVA was dissolved in sufficient amount of water. Thiocolchicoside and Famotidine was dissolved in methanol and maintained at room temperature. The latter dispersion containing dissolved polymer under constant stirring condition (300rpm) kept at room temperature. The stirring was continued and bridging liquid dichloromethane was added drop wise to obtain agglomerates, which were then filtered and dried overnight^13-15. Different batches were prepared by changing the concentration of PVA and HPMC K15M.

Table 1: Formulation chart of co-agglomerates

Formulation	F1	F2	F3	F4	F5	F6
Thiocolchicoside (gm)	0.15	0.15	0.15	0.15	0.15	0.15
Famotidine(gm)	0.4	0.4	0.4	0.4	0.4	0.4
PVA (gm)	0.25	0.50	0.75	-	-	-
HPMC K15M (gm)	-	-	-	0.25	0.50	0.75
% Water-%Methanol-%Dichloromethane	1:1:1	1:1:1	1:1:1	1:1:1	1:1:1	1:1:1

Evaluation parameters:

Micromeritics Study^16-19:

Agglomerates (10g) were accurately weighed and transferred to a suitable graduated cylinder. The cylinder was then gently tapped to the base on a slightly resilient surface, such as a rubber pad or book, until the height of the sample in the cylinder reached at a minimum that is the sample height does not reduce with further tapping. Volume of sample in cc (ml) was read off.

D_t= M/V_t

Where,

D_t = Tapped density (g/ml), M = Mass of powder (g)

V_t = Tapped volume of powder (ml)

Bulk density:

Sample (10g) was passed through a sieve with aperture of 1.0mm. In a measuring cylinder, sample up to 250ml was introduced gently without compacting. The unsettled apparent volume was read and bulk density was calculated using following formula.

D_b= M/V_o

Where,

M= Mass of powder (gm/cc)

V_o = Bulk volume of powder (ml)

Compressibility index (CI): It is a manifestation of the compressibility of a powder. And it was calculated by using following equation,

I = (1-V/V_o) × 100

Where,

V= the volume occupied by the sample of powder after being subjected to standardized tapping procedure and

V_o= the volume before tapping

Hausner’s ratio:

Hausner’s ratio is defined as a ratio of a tapped density to bulk density. It’s a measure of relative importance of interparticulate interactions. Tapped density and bulk density were measured and therefore the Hausner’s ratio was calculated using the subsequent equation.

Hausner ratio = Bulk density/Tapped density

Angle of repose:

Angle of repose is defined as the maximum angle possible between the surfaces of pile of powder and horizontal plan. The angle of repose for the powder of every formulation was determined by the funnel method. The powder was made to permit effuse of the funnel opening fixed at a height of 2cm from the surface on a plane paper kept on the horizontal platform. After this, gradual addition of the powder from the funnel mouth was done which forms a pile of powder at the surface, this was continued until the pile touch the tip of the funnel. A circle was drawn round the pile base to calculate the radius of the powder cone was measured. Angle of repose was calculated with the utilization of the subsequent equation.

Ө = tan^-1[h/r]

Where,

h = height of pile formed

r = radius of pile formed

Drug content and Percentage yield²⁰:

Drug content is that the ratio of experimentally measured drug content to the theoretical value, expressed as percentage (%). An accurately weighed quantity (50mg) of prepared agglomerates was dissolved in 100ml of phosphate buffer 6.8. This solution is then appropriately diluted and drug content was estimated by UV spectrophotometer at 272nm for Thiocolchicoside and 421nm for Famotidine.

The percentage yield (%) of samples was calculated using following equation,

% Yield = Total weight of agglomerates ×100

Total weight of drug and polymer

% Drug Content = Practical Yield ×100

Theoretical Yield

In-Vitro Dissolution Study:

Dissolution behavior of pure Thiocolchicoside and Famotidine with comparison to the prepared agglomerates was studied using phosphate buffer pH 6.8 as dissolution medium. Drug (50mg) in muslin cloth was placed in basket containing 300ml of solution of pH 6.8 for 3 hours. After 30 min of time interval, 5ml of solution was withdrawn and diluted with buffer 6.8 solutions and analyzed at 272nm for Thiocolchicoside and 421nm for Famotidine using UV-spectrophotometer ¹⁸. After the dilution same amount of freshly prepared phosphate buffer was replaced in the dissolution chamber to maintain the sink condition. The cumulative drug release (% CDR) of the prepared agglomerates was then calculated for every batch containing different concentration of polymers. The in vitro dissolution studies were performed using paddle type having 8 Station USP type-II dissolution apparatus. The dissolution studies were administered in 900ml acid buffer of pH 1.2 for first 2 hours then it absolutely was replaced by 900ml phosphate buffer having pH 6.8 for next 10 hours. The dissolution medium was kept in a very thermostatically controlled water bath, maintained at 37±0.5°C. The paddles were rotated at 50rpm. After specific time interval5ml of sample were withdrawn and dilutions were made if necessary.

Evaluation of Optimized Batch of Crystallo-Co-Agglomerates:

X-ray diffraction study (XRD): X-ray diffraction spectra of Thiocolchicoside, Famotidine and ready agglomerates were recorded with x-ray diffractometer employing using tube anode (Cu Ka λ = 1.5406) at 45Kv and 40mA. The data were recorded over a variety of 20 to 100 at a scanning rate of 30.36 s/step cps using continuous scan mode. The relative intensity I/I0 and interplanar distance (d) like the 2θ values were reported and compared.

Particle size distribution:

The particle size distribution was meted out with the assistance of Laser diffraction technique. The sample is dispersed in suitable liquid media during which it's insoluble but having wetting property. The laser passes by the dispersed medium and is diffracted by the particles. The laser diffraction pattern depends upon the particle size. The laser pattern is measured and correlated to the particle size distribution.

Stability Study:

The need of stability testing is to test the product and also to provide evidence on how the quality of a drug substance or drug product varies with time underneath the influence of assorted environmental factors like temperature, light, humidity, and allows suggested storage conditions, re-test periods and shelf lives to be established²⁰.

In the present study, stability studies were carried out at Room Temperature: 25°C±2°C/60% RH ±5% RH and Accelerated testing: 40°C±2°C/75% RH ±5% RH for 3 months for the optimized formulation. The optimized formulation was analyzed for the % drug release and % drug content.

RESULT:

Drug-Excipients Interaction: From the peaks obtained in the results of FT-IR study, it was found that there were no physical or chemical interactions between the drug and the polymer as there was no disappearance, mismatch or formation of any new peak when matched with the standard reference.

Standard Calibration Curve: From the scanning of Thiocolchicoside and Famotidine in phosphate buffer (pH 6.8), it was concluded that the λ max of Thiocolchicoside was 272nm and for Famotidine was 421nm. From the standard calibration curve it was found that Thiocolchicoside and Famotidineobeys beer’s- lamberts’ law in the range of 10 -50µg/ml. The equation of linear line was found to be, y= 0.014X + 0.139, R²= 0.997. Correlation coefficient (R²) value indicates the linear correlation between concentration and absorbance.

Fig 2: Standard Calibration Curve of Thiocolchicoside

Fig 3: Standard Calibration Curve of Famotidine

Micromeritics Evaluation:

The micromeritics evaluation of pure drug mixture (1:1) of Thiocolchicoside and Famotidine showed the tap density of 0.50 +0.004 gm/cm³, bulk density 0.18 +0.003 gm/cm³, carr’s index 22.66 +0.11, Hausner’s ratio 1.28 +0.03 and angle of repose 24.56⁰+0.22 respectively and the micromeritics of prepared agglomerates showed that there is a increase in flow and also enhancement of all the properties.

Table 2: Micromeritics Evaluation of Prepared Agglomerates

Batch No.	Tap Density (gm/cm³)	Bulk Density (gm/cm³)	Carr’s Index	Hauser’ s Ratio	Angle of Repose
F1	0.713±0.36	0.752±0.04	6.7	1.07	19.60⁰±0.25
F2	0.797±0.02	0.786±0.36	4.8	1.03	21.25⁰±0.71
F3	0.833±0.06	0.878±0.17	7.2	1.04	16.87⁰±0.06
F4	0.883±0.58	0.784±0.29	6.3	1.08	19.58⁰±0.02
F5	0.922±0.12	0.862±0.07	4.3	1.03	18.84⁰±0.08
F6	0.929±0.07	0.902±0.03	6.1	1.05	15.88⁰±0.47

Drug Content and Percentage Yield:

From the prepared co-agglomerates it was seen that the formulation F4 shows the maximum drug content of 95.68±0.82 which means that form all other batches it is having a maximum drug entrapment.

Table 3: Evaluation of % Drug Content and % Yield

Formulation	%Drug content of Thiocolchicoside	%Drug content of Famotidine	% Yield of Agglomerates
F1	89.25±0.25	85.35±0.15	90.38±0.25
F2	85.35±0.07	86.37±1.27	88.64±0.03
F3	83.75±0.03	89.85±2.03	84.12±0.72
F4	95.68±0.82	96.88±0.79	85.24±0.08
F5	89.46±0.41	89.66±0.81	82.36±0.67
F6	82.81±0.21	82.31±0.61	81.20±0.28

% Cumulative Drug Release:

From the results obtained by dissolution study it was seen that the formulation F4 shows the maximum sustained release effect in the time period of 12 hours than compared with other formulations.

Table 4: % Cumulative Drug Release of Thiocolchicoside (‘F’ indicates drug release of Thiocolchicoside and ‘FF’ indicates drug release of Famotidine)

Time (hrs)	F1	F2	F3	F4	F5	F6	Pure Drug- Thiocolch icoside	FF1	FF2	FF3	FF4	FF5	FF6	Pure Drug- Famotidine
0.5	8.854	2.241	6.126	10.65	0.203	1.134	32.95	7.854	4.24	6.23	12.65	1.516	1.144	35.47
1	15.77	14.81	7.26	20.40	1.581	5.786	45.25	18.77	18.81	7.26	25.40	2.581	6.786	48.58
2	16.97	21.36	8.94	25.67	3.24	9.678	58.70	19.97	24.36	8.17	29.67	4.24	8.678	59.69
4	29.34	38.68	19.87	31.76	16.24	37.81	60.82	25.34	36.68	17.87	36.76	19.24	29.81	68.62
6	32.77	54.34	32.67	44.23	52.66	59.87	77.11	38.77	57.34	33.67	47.23	48.66	58.87	78.04
8	67.89	69.98	47.89	51.56	73.67	68.67	89.33	77.89	68.98	49.89	55.56	69.67	76.97	87.52
10	73.04	78.42	78.90	63.56	88.75	88.83	99.41	81.04	76.42	71.90	68.56	79.75	89.53	99..24
12	89.55	89.25	98.34	72.68	92.08	99.02		90.55	90.25	95.34	73.87	89.99	95.12

DISCUSSION:

From the prepared agglomerates of Thiocolchicoside and Famotidine was seen that the agglomerates showed a better flow property, better dissolution time and better stability of the optimized formulation. The various micromeritics parameters evaluated of prepared agglomerates where found to in the range of tap density 0.713±0.36 - 0.929±0.007gm/cm², bulk density 0.752±0.04 – 0.902±0.003gm/cm², carr’s index 4.3-7.2 Hausner’s ratio 1.03-1.08 and angle of repose 15.88⁰±0.47 – 21.25⁰±0.71 whereas the micromeritics property of pure drug mixture was found to be tap density 0.50±0.004, bulk density 0.18±0.003, carr’s index 22.66±0.11, Hausner’s ratio 1.28±0.03 and angle of repose 24.56⁰±0.22. The % drug content of Thiocolchicoside was found to be in the range of 82.81±0.21–95.68±0.82 while of Famotidine 82.31±0.61 – 96.88±0.79. The % yield was found to be in the range of 81.20±0.28 – 90.38±0.25. The cumulative drug release of Thiocolchicoside was found to be in the range of 32.95-99.41% while of Famotidine 35.47-98.15%. The cumulative drug release of Thiocolchicoside prepared agglomerates was found to be in the range of 0.203-99.02% while the release of Famotidine was 1.516-95.34%. From all the above evaluation parameters it was found that the F4 batch was optimum as it showed maximum drug content of Thiocolchicoside and Famotidine i.e. 95.68±0.82% and 96.88±0.79%. The cumulative drug release of the F4 batch was seen to give more sustained release of 10.65-72.68% for Thiocolchicoside and 12.65-73.87% for Famotidine. The stability study indicated that the prepared formulation was having no significance decrease in the % drug release and in % drug release.

CONCLUSION:

The method for preparation of crystal- co-agglomerates was successful method for improvising the dissolution, flow ability, and stability of the drug which will help to give more bioavailability in the body by reducing the hepatic first pass metabolism. The dissolution and disintegration rate of agglomerate was increased in presence of HPMC K15M.From the above experiment, it can be concluded that this method is proficient for creating spherical agglomerates with enhanced micromeritics, mechanical and conventional properties.

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Received on 14.09.2021 Modified on 07.12.2021

Asian J. Pharm. Res. 2022; 12(2):125-131.

DOI: 10.52711/2231-5691.2022.00019

Day(s)	Room Temp	%Drug content of Thiocolchicoside	% Drug content of Famotidine	% Drug Release in 12 hours	Accelerated Study	%Drug content of Thiocolchicoside	% Drug content of Famotidine	% Drug Release in 12 hours
0	25°C ± 2°C / 60 % RH ± 5% RH	95.68±0.82	89.25±0.25	72.68	40°C ± 2°C / 75 % RH ± 5% RH	95.28±0.84	85.35±0.15	73.87
30		95.58±0.97	89.17±1.05	72.98		95.15±0.32	85.05±0.05	73.99
60		95.28±0.62	88.05±0.38	73.01		94.98±0.64	84.85±0.12	74.10
90		94.92±0.25	88.89±0.75	73.18		94.72±0.44	84.55±1.01	74.25