Formulation and characterization of antibiotic drug loaded aquasome for the topical application

Figures & data

Table 1. Factor and levels of formulation.

		Factor 1	Factor 2	Response 1	Response 2
Std	Run	A:Ca3(PO4) (gm)	B:Trehalose (mg)	Entrapment efficacy %	In vitro drug release %
6	1	4.4	150	19.2	47.5
2	2	4	100	19	45.3
12	3	3	150	23	57.2
7	4	3	79	21.2	48.2
4	5	4	200	19.2	50.2
8	6	3	220	23.4	62.3
11	7	3	150	23.4	57.3
3	8	2	200	35	62
10	9	3	150	23.1	57.2
1	10	2	100	30	50
5	11	1.5	150	21	55
13	12	3	150	23	57
9	13	3	150	23.2	57.3

Factor 1: Represents the first factor studied in the experiment (A:Ca3(PO4)). Factor 2: Represents the second factor studied in the experiment (B: Trehalose). Std Run: Standard Run number for the experiment. A:Ca3(PO4): Amount of Ca3(PO4) used in the formulation. B: Trehalose: Amount of Trehalose used in the formulation. Response 1: Entrapment efficacy of the aquasome formulation. Response 2: In vitro drug release from the aquasome formulation.

%: Percentage; gm: Gram; mg: Milligram.

Table 2. Response surface regression: analysis of variance.

Response 1: entrapment efficacy
Source	Sum of squares	df	Mean square	F-value	p-value
Model	116.28	2	58.14	4.56	0.0391	Significant
A-Ca3(PO4)	107.65	1	107.65	8.44	0.0157
B-Trehalose	8.63	1	8.63	0.6772	0.4297
Residual	127.51	10	12.75
Lack of fit	127.40	6	21.23	758.33	<0.0001	significant
Pure error	0.1120	4	0.0280
Cor total	243.79	12
Response 2: in vitro drug release
Source	Sum of squares	df	Mean square	F-value	p-value
Model	356.27	5	71.25	53.41	<0.0001	Significant
A-Ca3(PO4)	91.85	1	91.85	68.85	<0.0001
B-Trehalose	169.65	1	169.65	127.17	<0.0001
AB	12.60	1	12.60	9.45	0.0180
A^2	76.62	1	76.62	57.43	0.0001
B^2	12.10	1	12.10	9.07	0.0196
Residual	9.34	7	1.33
Lack of fit	9.28	3	3.09	206.18	<0.0001	Significant
Pure error	0.0600	4	0.0150
Cor total	365.61	12

Statistical analysis results showing the significance of factors A (Ca3(PO4)) and B (Trehalose) on Response 1 (Entrapment efficacy) and Response 2 (in vitro drug release), with p-values indicating significance levels.

Ca3(po4): Calcium phosphate; df: Degree of freedom.

Figure 1. Response surface plot and counter plot of relationship between A:ca3(po4) and B:trehalose on entrapment efficacy(I & II) and in vitro drug release (III & IV) of formulation.

Indicates the magnitude of entrapped efficacy (%), Contour lines: Represent levels of drug release (%) corresponding to different combinations of Factor 1 and Factor 2.

ca3(po4): Calcium phosphate, color scale.

Table 3. FTIR peaks of calcium phosphate core, Trehalose coated core and cephalothin-loaded aquasome.

Formulation	Wavelength (cm^-1)	Groups
Calcium phosphate core	507.28, 983.70, 1051.20, 1120.64, 1330.88, 1631.78, 3226.91	C-I, -CH2 rock, C-O, -NH3^+ rock, -CH3 bend, C = C, -OH
Trehalose coated core	387.69, 516.92, 875.68, 987.55, 1055.06, 1122.57, 1348.24	C-I, C-Br, C-C-N, -CH2 rock, C-O, -NH3^+ rock, -CH2 twist
Cephalothin loaded aquasome	513.07, 856.39, 987.55, 1051.20, 1120.64, 1348.24, 2355.08	C-Br, C-C-N, -CH2 rock, C-O, -NH3^+ rock, -CH2 twist, C-N

The formulations exhibit distinct peaks at specific wavelengths, indicative of the presence of particular functional groups.

cm-1: Reciprocal wavelength.

Figure 2. SEM (left panel) and EDX (right panel) analysis of calcium phosphate core (A), trehalose coated core (B) and Cephalothin loaded aquasome (C).

SEM, which shows the presence of spherical calcium phosphate core in the nano range.

μm: Micrometer; KeV: Kilo-electron volt; SEM: Scanning electron microscopy.

Table 4. Particle size of calcium phosphate core, Trehalose coated core and cephalothin-loaded aquasome.

Characteristics	Calcium phosphate core	Trehalose coated core	Cephalothin loaded aquasome
Z-Average (d.nm)	414	670	849
Polydispersity index (PDI)	0.350	0.237	0.200
Intercept	0.929	0.917	0.828
Size (d.nm)	265	309	452
St Dev (d.nm)	28.8	31.5	41.7

The cephalothin-loaded aquasome exhibits smaller particle sizes and a more uniform size distribution.

nm: Nanometer; PDI: Polydispersity index.

Figure 3. The size and Z-Average of calcium phosphate core, Trehalose coated core and cephalothin-loaded aquasome.

Comparison of particle sizes in each step of preparing drug loaded aquasomes.

nm: Nanometer.

Table 5. Result of stability study.

Time (months)	Temperature (°C)	Size (nm)	%EE	Physical appearance
1	4 ± 0.20	457 ± 10	62% ± 2	Normal
2	4 ± 0.20	458 ± 13	60% ± 3	Normal
3	4 ± 0.20	460 ± 9	62% ± 2	Normal

The table presents data collected over a three-month period, where each row corresponds to a specific time point. The parameters recorded include the temperature (maintained at 4°C ± 0.20°C), the size of the particles (reported in nanometers ± standard deviation), the percentage of encapsulation efficiency (%EE ± standard deviation) and the physical appearance of the samples.

%EE: Percentage entrapment efficacy; °C: Degree celsius; nm: Nanometer.