Optimised nanoformulation of bromocriptine for direct nose-to-brain delivery: biodistribution, pharmacokinetic and dopamine estimation by ultra-HPLC/mass spectrometry method

Figures & data

Figure 1. Percentage radioactivity remaining in the nose after different time intervals for BRC-loaded CS NPs and BRC solution (control) (n = 3, mean ± SD) is shown.

Table 1. Validation data of BRC in biological samples.

Biological samples	Nominal concentration (ng/ml)	Intra-batch precision			Inter-batch precision
		Determined concentration (ng/ml)	% RSD	% Accuracy	Determined concentration (ng/ml)	% RSD	% Accuracy
Plasma	0.5	0.53 ± 0.005	0.95	107.1	0.52 ± 0.01	1.93	105.9
	4	4.14 ± 0.058	1.41	103.5	4.11 ± 0.05	1.22	102.9
	8	7.24 ± 0.127	1.75	90.5	7.54 ± 0.12	1.61	94.2
Brain homogenates	0.5	0.49 ± 0.002	0.45	98.98	0.46 ± 0.003	0.66	93.30
	4	3.85 ± 0.079	2.06	96.30	3.93 ± 0.040	1.04	98.34
	8	7.62 ± 0.048	0.63	95.31	7.69 ± 0.138	1.79	96.13

BRC: Bromocriptine; RSD: Relative standard deviation.

Figure 3. Typical chromatograms of (A) extracted BRC from plasma; (B) extracted BRC from brain homogenates are shown.

Figure 2. Mass spectrum of BRC precursor ion (protonated precursor [M+H]+ ions at m/z 656.12) and propranolol precursor ion (protonated precursor [M+H]+ ions at m/z 260.10) are shown.

Table 2. Stability data of BRC in biological samples under different conditions.

Exposure condition	Theoretical concentration	Plasma			Brain
		Determined concentration (ng/ml)	% RSD	% Accuracy	Determined concentration (ng/ml)	% RSD	% Accuracy
Bench-top stability (25°C for 24 h)	4	4.03 ± 0.190	4.73	100.80	3.78 ± 0.04	1.16	94.66
	8	8.20 ± 0.80	9.81	102.58	7.76 ± 0.09	1.19	97.05
Long-term stability (−80°C for 30 days)	4	3.89 ± 0.10	2.71	97.47	3.64 ± 0.06	1.86	91.04
	8	7.89 ± 0.237	3.00	98.73	7.56 ± 0.10	1.38	94.53

BRC: Bromocriptine; RSD: Relative standard deviation.

Figure 4. Degradation products obtained after (A) acidic stress; (B) alkaline stress; (C) oxidation stress; (D) sunlight and (E) thermal stress are shown.

Table 4. Pharmacokinetic parameters of BRC solution and BRC-loaded CS NPs in mice following intravenous (i.v.) and intranasal (i.n.) administration.

Formulations	Brain and plasma samples	Cmax (ng/ml)	Tmax (h)	t1/2(h)	Ke (h^-1)	AUC 0 – 480 (ng h/ml)	AUC0 – ∞ (ng h/ml)
BRC solution (i.n.)	Brain	0.185 ± 0.01	1.0	9.73 ± 2.09	0.074 ± 0.01	0.937 ± 0.02	1.992 ± 0.27
	Blood	0.315 ± 0.01	2.0	9.48 ± 1.6	0.074 ± 0.01	1.559 ± 0.05	2.990 ± 0.39
BRC-loaded CS NPs (i.n.)	Brain	0.569 ± 0.008	1.0	5.58 ± 0.72	0.125 ± 0.01	2.339 ± 0.07	3.618 ± 0.37
	Blood	0.645 ± 0.01	2.0	5.12 ± 0.35	0.136 ± 0.009	2.655 ± 0.08	3.857 ± 0.28
BRC-loaded CS NPs (i.v.)	Brain	0.259 ± 0.08	1.0	6.07 ± 1.69	0.121 ± 0.03	0.966 ± 0.09	1.607 ± 0.34
	Blood	0.823 ± 0.09	1.0	4.24 ± 0.67	0.166 ± 0.02	2.740 ± 0.33	3.839 ± 0.38

BRC: Bromocriptine; CS NPs: Chitosan nanoparticles.

Table 3. Brain and blood distribution of BRC solution and BRC-loaded CS NPs in mice after intranasal (i.n.) and intravenous (i.v.) administration.

Formulation	Biological samples	0.5 h (ng/ml)	1 h ng/ml	2 h (ng/ml)	4 h (ng/ml)	8 h (ng/ml)
BRC solution (i.n.)	Brain	0.088 ± 0.019	0.185 ± 0.013	0.165 ± 0.011	0.119 ± 0.008	0.075 ± 0.007
	Blood	0.121 ± 0.008	0.243 ± 0.008	0.315 ± 0.014	0.211 ± 0.015	0.103 ± 0.008
BRC-loaded CS NPs (i.n.)	Brain	0.250 ± 0.013	0.569 ± 0.008	0.458 ± 0.010	0.262 ± 0.022	0.157 ± 0.022
	Blood	0.262 ± 0.022	0.582 ± 0.009	0.645 ± 0.011	0.265 ± 0.021	0.161 ± 0.020
BRC-loaded CS NPs (i.v.)	Brain	0.106 ± 0.020	0.259 ± 0.081	0.184 ± 0.008	0.100 ± 0.014	0.071 ± 0.016
	Blood	0.425 ± 0.021	0.822 ± 0.099	0.657 ± 0.045	0.290 ± 0.076	0.176 ± 0.031

BRC: Bromocriptine; CS NPs: Chitosan nanoparticles.

Figure 5. Concentration–time profile of (A) brain concentration (B) plasma concentration and (C) brain:blood ratio of BRC solution and BRC-loaded CS NPs in mice after intranasal (i.n.) and intravenous (i.v.) administration (n = 3, mean ± SD) is shown.

Figure 6. Brain section of (A) normal mice, (B) haloperidol-treated mice and (C) combined treatment of haloperidol and BRC-loaded CS NPs (i.n.)-treated mice is shown.

Figure 7. Representation of (A) log percentage drug remaining versus time and (B) Arrhenius plot for optimised BRC-loaded CS NPs.