**4. Results and discussion**

#### **4.1 Morphological analysis of hydrogel beads**

Image of the swollen beads is shown in **Figures 2** and **3**. Beads obtained has diameter of 0.50 cm. Morphological features of curcumin loaded and unloaded beads were analysed through SEM images shown in **Figure 4**.

The morphological features of curcumin loaded and unloaded beads were analysed by recording the SEM images as shown in **Figure 4**.

Hydrogel beads containing alginate were smoother and more spherical compared to the beads consisting of alginate and carrageenan. This effect can be attributed to the higher cross linking ability of alginate relative to carrageenan. This cross linking takes place instantaneously upon dropping sodium alginate into the cross linking solution (consisting of Ca2+) leading to geometrically stable particles.

In the case of formulations containing carrageenan, the beads were less spherical, having rough and folded surfaces. This behaviour could be attributed to the low concentration of K+ in the hardening solution, and also to the reduced cross-linking efficiency of carrageenan as compared to alginate, which led to the production of non-spherical and less physically stable beads. The alginate-gelatin hydrogel beads show a smooth and homogeneous morphology, suggesting component miscibility and blend homogeny.

#### **4.2 Swelling degree**

#### *4.2.1 Effect of alginate, κ-carrageenan and gelatin ratios on swelling*

In the case of alginate-gelatin and alginate/κ-carrageenan hydrogel beads, the effect of sodium alginate on swelling of the hydrogel beads has been studied by varying its amount in the polymer blend in the range 50–80% (w/w). The results shown in **Figures 5** and **6**, clearly indicates that initially at 50% of alginate

**85**

**Figure 2.**

**Figure 3.**

*Image of the swollen beads.*

*Preparation of hydrogel beads and drug loading.*

*Preparation and Characterisation of Niosomal Emulsions as Novel Drug Delivery Vehicle…*

content in the hydrogel beads, the swelling ratio is high, while beyond this amount (70–80%) a fall in swelling degree is observed. The observed initial increase in the swelling degree could be attributed to the fact that since alginate is a linear anionic hydrophilic polymer, its increasing amount in the hydrogel beads cause an increased hydrophilicity of the polymer network with fixed ionic charges and enhanced repulsion among the polymer chains. This leads to greater swelling. However the decrease in swelling degree observed beyond 50% can be attributed to the fact that increase in alginate content results in a compact polymer network. This will form small pore sizes that slow down the diffusion of water molecules into the hydrogel

The effect of gelatin on the swelling degree of the alginate/gelatin hydrogel beads has been studied by varying the amount of gelatin in the polymer blend in the range 20–50% (w/w). **Figure 5** clearly indicates that, an increase in swelling

beads and consequently the swelling degree decreases.

*DOI: http://dx.doi.org/10.5772/intechopen.86942*

*Preparation and Characterisation of Niosomal Emulsions as Novel Drug Delivery Vehicle… DOI: http://dx.doi.org/10.5772/intechopen.86942*

**Figure 2.** *Preparation of hydrogel beads and drug loading.*

*Role of Novel Drug Delivery Vehicles in Nanobiomedicine*

SD, in percentage, was calculated using Eq. (1)

SD = W\_\_\_\_\_\_\_ <sup>s</sup> <sup>−</sup> Wd

release was calculated by using the following formula,

**4.1 Morphological analysis of hydrogel beads**

beads were analysed through SEM images shown in **Figure 4**.

analysed by recording the SEM images as shown in **Figure 4**.

*4.2.1 Effect of alginate, κ-carrageenan and gelatin ratios on swelling*

**3.4 Release study of curcumin**

**4. Results and discussion**

concentration of K+

and blend homogeny.

**4.2 Swelling degree**

C. The swelled samples were taken from the PBS at selected time intervals of 1, 2, 3, 4, and 10 up to 24 h, wiped with tissue paper, weighed and placed again in PBS. The

where Ws and Wd are the weights of swollen and dry beads, respectively.

The cumulative release of curcumin from hydrogel beads was carried out through incubating samples while shaking at 100 rpm in 20 ml of buffer solution (PBS) at pH 7.4 (1, 2, 3, 4, 10 up to 24 h incubation) at 37°C. After incubation, 3 ml sample was taken out from the buffer solution and analysed by UV-Vis spectrophotometer (Lambda 25-PerkinElmer UV-vis spectrophotometer) at max of 430 nm. The withdrawn volume of the sample was replaced with equal volume of fresh buffer solution to keep the volume of release fluid constant. The percentage drug

Percentage drug release = (Amount of drug released/

Image of the swollen beads is shown in **Figures 2** and **3**. Beads obtained has diameter of 0.50 cm. Morphological features of curcumin loaded and unloaded

The morphological features of curcumin loaded and unloaded beads were

Hydrogel beads containing alginate were smoother and more spherical compared to the beads consisting of alginate and carrageenan. This effect can be

attributed to the higher cross linking ability of alginate relative to carrageenan. This cross linking takes place instantaneously upon dropping sodium alginate into the cross linking solution (consisting of Ca2+) leading to geometrically stable particles. In the case of formulations containing carrageenan, the beads were less spherical, having rough and folded surfaces. This behaviour could be attributed to the low

efficiency of carrageenan as compared to alginate, which led to the production of non-spherical and less physically stable beads. The alginate-gelatin hydrogel beads show a smooth and homogeneous morphology, suggesting component miscibility

In the case of alginate-gelatin and alginate/κ-carrageenan hydrogel beads, the effect of sodium alginate on swelling of the hydrogel beads has been studied by varying its amount in the polymer blend in the range 50–80% (w/w). The results shown in **Figures 5** and **6**, clearly indicates that initially at 50% of alginate

in the hardening solution, and also to the reduced cross-linking

Wd <sup>∗</sup> <sup>100</sup> (%) (1)

Amount of drug loaded) ∗ 100 (2)

**84**

**Figure 3.** *Image of the swollen beads.*

content in the hydrogel beads, the swelling ratio is high, while beyond this amount (70–80%) a fall in swelling degree is observed. The observed initial increase in the swelling degree could be attributed to the fact that since alginate is a linear anionic hydrophilic polymer, its increasing amount in the hydrogel beads cause an increased hydrophilicity of the polymer network with fixed ionic charges and enhanced repulsion among the polymer chains. This leads to greater swelling. However the decrease in swelling degree observed beyond 50% can be attributed to the fact that increase in alginate content results in a compact polymer network. This will form small pore sizes that slow down the diffusion of water molecules into the hydrogel beads and consequently the swelling degree decreases.

The effect of gelatin on the swelling degree of the alginate/gelatin hydrogel beads has been studied by varying the amount of gelatin in the polymer blend in the range 20–50% (w/w). **Figure 5** clearly indicates that, an increase in swelling

#### **Figure 4.**

*SEM micrographs of unloaded (A) alginate/κ-*Car*, (B) alginate/gelatin hydrogel beads and curcumin loaded, (C) alginate/κ*-Car*, (D) alginate/gelatin hydrogel beads.*

#### **Figure 5.**

*Effect of alginate/gelatin weight ratio's on the swelling of the alginate/gelatin composite hydrogel beads at different polymer concentrations (a) 1%, (b) 1.5%, (c) 2%, (d) 2.5%.*

degree is observed with increase in gelatin content. An increase in the amount of gelatin in hydrogel beads enhances the hydrophilicity of polymer network and leads to higher swelling degree. The effect of κ-carrageenan on swelling degree of

**87**

**Figure 6.**

2.5% and weight ratio 50:50.

**4.3 Curcumin release study**

*4.3.1 Effect of alginate on curcumin release*

*with polymer concentrations (a) 1%, (b) 1.5%, (c) 2%, (d) 2.5%.*

*Preparation and Characterisation of Niosomal Emulsions as Novel Drug Delivery Vehicle…*

alginate/κ-carrageenan hydrogel beads has been studied by varying the amount of κ-carrageenan in the range 20–50% (w/w). The results showed in **Figure 6** shows the swelling degree of alginate/κ-carrageenan hydrogel beads increases with increase in carrageenan content. With increase in carrageenan content, the beads become less compact in structure and large pores and surface cavities were observed in the hydrogel beads. The alginate/κ-carrageenan (50:50) hydrogel beads show a higher degree of swelling than the alginate/gelatin (50:50) hydrogel beads. Swelling behaviour of hydrogel beads were examined by varying polymer concentration (1, 1.5, 2, 2.5%). As shown in **Figures 5** and **6**, increase in polymer concentration leads to enhancement in the swelling degree of both hydrogel beads. In both cases, hydrogel beads with polymer concentration 2.5% show the highest swelling. Comparison of the swelling degree of alginate/κ-carrageenan hydrogel beads with alginate/gelatin hydrogel beads shows that the former one with polymer concentration 2.5% and weight ratio 50:50 has higher degree of swelling than latter alginate/gelatin hydrogel beads with polymer concentration

*Effect of alginate/κ-carrageenan weight ratio's on the swelling of the alginate/κ-carrageenan hydrogel beads* 

Curcumin release studies were carried out in PBS (pH 7.4). Upon variation of sodium alginate ratio in the range 50–80% (w/w) in the polymer blend, the amount of curcumin released was found to diminish with time. This observation could be explained on the basis of swelling behaviour of hydrogel beads as discussed earlier. Moreover, by increasing the amount of alginate content, volume fraction of alginate

*DOI: http://dx.doi.org/10.5772/intechopen.86942*

*Preparation and Characterisation of Niosomal Emulsions as Novel Drug Delivery Vehicle… DOI: http://dx.doi.org/10.5772/intechopen.86942*

**Figure 6.** *Effect of alginate/κ-carrageenan weight ratio's on the swelling of the alginate/κ-carrageenan hydrogel beads with polymer concentrations (a) 1%, (b) 1.5%, (c) 2%, (d) 2.5%.*

alginate/κ-carrageenan hydrogel beads has been studied by varying the amount of κ-carrageenan in the range 20–50% (w/w). The results showed in **Figure 6** shows the swelling degree of alginate/κ-carrageenan hydrogel beads increases with increase in carrageenan content. With increase in carrageenan content, the beads become less compact in structure and large pores and surface cavities were observed in the hydrogel beads. The alginate/κ-carrageenan (50:50) hydrogel beads show a higher degree of swelling than the alginate/gelatin (50:50) hydrogel beads. Swelling behaviour of hydrogel beads were examined by varying polymer concentration (1, 1.5, 2, 2.5%). As shown in **Figures 5** and **6**, increase in polymer concentration leads to enhancement in the swelling degree of both hydrogel beads. In both cases, hydrogel beads with polymer concentration 2.5% show the highest swelling. Comparison of the swelling degree of alginate/κ-carrageenan hydrogel beads with alginate/gelatin hydrogel beads shows that the former one with polymer concentration 2.5% and weight ratio 50:50 has higher degree of swelling than latter alginate/gelatin hydrogel beads with polymer concentration 2.5% and weight ratio 50:50.

## **4.3 Curcumin release study**

#### *4.3.1 Effect of alginate on curcumin release*

Curcumin release studies were carried out in PBS (pH 7.4). Upon variation of sodium alginate ratio in the range 50–80% (w/w) in the polymer blend, the amount of curcumin released was found to diminish with time. This observation could be explained on the basis of swelling behaviour of hydrogel beads as discussed earlier. Moreover, by increasing the amount of alginate content, volume fraction of alginate

*Role of Novel Drug Delivery Vehicles in Nanobiomedicine*

*(C) alginate/κ*-Car*, (D) alginate/gelatin hydrogel beads.*

**86**

**Figure 5.**

**Figure 4.**

degree is observed with increase in gelatin content. An increase in the amount of gelatin in hydrogel beads enhances the hydrophilicity of polymer network and leads to higher swelling degree. The effect of κ-carrageenan on swelling degree of

*Effect of alginate/gelatin weight ratio's on the swelling of the alginate/gelatin composite hydrogel beads at* 

*different polymer concentrations (a) 1%, (b) 1.5%, (c) 2%, (d) 2.5%.*

*SEM micrographs of unloaded (A) alginate/κ-*Car*, (B) alginate/gelatin hydrogel beads and curcumin loaded,* 

**Figure 7.**

*Effect of alginate/gelatin weight ratio's on cumulative release of curcumin from the hydrogel beads with polymer concentrations (a) 1%, (b) 1.5%, (c) 2%, (d) 2.5%.*

in the hydrogel beads increases leading to the fact that curcumin molecules has to travel a long path in order to diffuse out through the swollen beads because of its characteristic size. This causes a slow release of curcumin from both the hydrogel beads.
