Lamotrigine loaded PLGA nanoparticles intended for direct nose to brain delivery in epilepsy: pharmacokinetic, pharmacodynamic and scintigraphy study

Figures & data

Table 1. Optimized formulation parameters for LTG-PNPs.

Parameter	Optimized value
Amount of PLGA (mg)	82
Concentration of Poloxamer 407 (%)	0.75
% EE	71.3 ± 2.0
Particle size (nm)	170.0 ± 2.8
% CDR at 24 h	94.5 ± 4.2
PDI	0.191 ± 0.035
Zeta potential (mV)	−16.60 ± 2.96

Figure 1. In-vitro release profiles of LTG-SOL & LTG-PNPs.

Figure 2. DSC Thermogram of (A) Pure LTG (B) LTG-PNPs.

Figure 3. X-ray diffractogram of (A) pure LTG (B) PLGA (C) Poloxamer 407 (D) LTG-PNPs.

Figure 4. TEM image of LTG-PNPs.

Figure 5. FTIR spectra of (A) Pure LTG (B) LTG-PNPs.

Figure 6. Ex-vivo permeation of LTG-SOL & LTG-PNPs across goat nasal mucosa.

Figure 7. Histopathological condition of goat nasal mucosa after treatment with (A) Phosphate buffer saline (PBS) pH 6.4 (B) Isopropyl alcohol (IPA) (C) LTG-SOL (D) LTG-PNPs.

Figure 8. Drug concentration versus time plot upon administration of ^99mTc-LTG-SOL (intranasal and intravenous)_. and ^99mTc-LTG-PNPs (intranasal) in BALB/c mice in (A) blood (B) brain.

Table 2. Biodistribution of ^99mTc-LTG-SOL_i.v., ^99mTc-LTG-SOL_i.n., ^99mTc-LTG-PNPs_i.n. in blood and brain at different time intervals in BALB/c Mice*.

		Sampling time points (min) (% radioactivity/g)
Formulation & route of dosing	Organ/tissue	0	15 min.	30 min.	60 min.	120 min.	240 min.	480 min.
^99mTc-LTG-SOLi.v.	Blood	0	1.390 ± 0.320	1.090 ± 0.242	0.775 ± 0.217	0.651 ± 0.024	0.410 ± 0.018	0.074 ± 0.004
	Brain	0	0.313 ± 0.002	0.052 ± 0.003	0.101 ± 0.002	0.072 ± 0.001	0.036 ± 0.002	0.003 ± 0.002
Brain/blood ratio		0	0.225	0.05	0.130	0.111	0.088	0.040
^99mTc-LTG-SOLi.n.	Blood	0	0.059 ± 0.073	0.074 ± 0.034	0.025 ± 0.025	0.017 ± 0.001	0.005 ± 0.001	0..002 ± 0.001
	Brain	0	0.017 ± 0.001	0.083 ± 0.002	0.018 ± 0.001	0.007 ± 0.002	0.001 ± 0.001	0.001 ± 0.001
Brain/blood ratio		0	0.288	1.121	1.059	0.412	0.200	0.500
^99mTc-LTG-PNPsi.n.	Blood	0	0.066 ± 0.001	0.062 ± 0.004	0.101 ± 0.005	0.102 ± 0.004	0.058 ± 0.003	0.047 ± 0.002
	Brain	0	0.098 ± 0.003	0.084 ± 0.020	0.097 ± 0.001	0.114 ± 0.005	0.057 ± 0.002	0.034 ± 0.012
Brain/blood ratio		0	1.485	1.355	0.960	1.118	0.982	0.723

*Each value is mean ± SD of three estimations.

Table 3. Pharmacokinetic Parameters of ^99mTc-LTG-SOL_i.v., ^99mTc-LTG-SOL_i.n. and ^99mTc-LTG-PNP_i.n. in BALB/c Mice.

Pharmacokinetic Parameter	^99mTc-LTG-SOL i.v.		^99mTc-LTG-SOL i.n.			^99mTc-LTG-PNP i.n.
	Blood	Brain	Blood		Brain	Blood	Brain
Cmax (%radioactivity/g)	1.390 ± 0.320	0.313 ± 0.002	0.074 ± 0.034		0.083 ± 0.002	0.102 ± 0.004	0.114 ± 0.005
Tmax (min)	15	15	30		30	120	120
AUC0–480 (min × % radioactivity/g)	453.84	42.45	9.7005		4.8225	82.59	76.005
Nasal bioavailability (%)			2.137		11.36	18.19	179.046
T1/2 (min)		305.21			336.32		963.33

Table 4. Drug targeting efficiency [DTE (%)] and direct target organ transport [DTI (%)] following administration of ^99mTc-LTG-SOL_i.n. and ^99mTc-LTG-PNPs_i.n.

Formulation	DTE (%)	DTI (%)
^99mTc-LTG-SOLi.n.	49.71	531.00
^99mTc-LTG-PNPsi.n.	92.03	984.17

Figure 9. Gamma scintigraphy images in rabbits following intranasal administration of (A) ^99mTc-LTG-SOL_. and (B) ^99mTc-LTG-PNPs.

Figure 10. Onset time of seizures in Pentylenetetrazole (PTZ)-induced convulsions in Albino Wistar rats.

Table 5. Time (s) for the development of seizures in male Albino Wistar rats (n = 6).

Formulation administered	Administration after 15 min	Administration after 30 min	Administration after 60 min
Control group	131.36 ± 3.06	135.25 ± 4.07	128.45 ± 3.45
LTG-SOLi.n.	187.08 ± 5.25*	255.78 ± 6.98*	210.06 ± 6.78*
LTG-SOLi.v.	160.68 ± 6.87*	165.26 ± 6.26*	160.35 ± 8.48*
LTG-PNPsi.n.	241.55 ± 5.96*$	440.84 ± 9.89*$	355.85 ± 9.88*$

*p < .05; Significant as compared to control group, One-way ANOVA followed by Tukey’s test.

*$<.05; Very significant as compared to LTG-SOL i.n. & LTG-PNPs i.v., One-way ANOVA followed by Tukey’s test.

Table 6. Stability study of LTG-PNPs (P10).

Conditions	Parameters	Initial	3 months	6 months
4 ± 2 °C (Refrigerator)	% EE	72.0 ± 2.5	70.2 ± 1.6	69.2 ± 3.1
	Particle size (nm)	206.2 ± 3.0	208.2 ± 3.5	211.3 ± 5.1
	CDR at 24 h (%)	93.3 ± 3.3	92.1 ± 2.4	90.6 ± 3.0
25 ± 2 °C/60 ± 5 %RH (Stability chamber)	% EE	72.0 ± 2.5	70.7 ± 3.1	72.0 ± 2.5
	Particle size (nm)	206.2 ± 3.0	214.0 ± 4.6	222.7 ± 4.1
	CDR at 24 h (%)	93.3 ± 3.3	89.3 ± 3.1	86.1 ± 2.6