Spray Dried Thiolated Chitosan Coated Sodium Alginate Multilayer Microparticles for Vaginal Anti-HIV Microbicide Delivery

Jianing Meng 1*, Vivek Agrahari 1*, Miezan J. Ezoulin 1, Sudhaunshu S. Purohit 2, Tao Zhang1, Agostino Molteni3, Daniel Dim4, Nathan A. Oyler 2, Bi-Botti C. Youan1**

1Laboratory of Future Nanomedicines and Theoretical Chronopharmaceutics Division of Pharmaceutical Sciences, University of Missouri-Kansas City, Kansas City, Missouri 64108

2Department of Chemistry, University of Missouri-Kansas City, Kansas City, Missouri 64110

3School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri 64108

4Truman Medical Center Hospital Hill, Kansas City, Missouri 64110

* Author contributed equally

** Correspondence to: Bi-Botti C. Youan (Tel: 816-235-2410; Fax: 816-235-5779; Email: )

1. Experimental design and optimization of spray dried MPs

The responses obtained by the custom design are shown in Table S1. The validity of the model is determined by ANOVA test, which is shown in Table S2. The P value is 0.0007, less than 0.05, indicating a statistically significant model fit at 95% confidence.

Table S1. Percent yield obtained by the custom experimental design.

No. / Polymer Mw / Polymer concentration (mg/ml) / Inlet T (°C) / Yield (%)
1 / Low / 15 / 150 / 48.3
2 / Low / 10 / 100 / 43.9
3 / High / 5 / 150 / 56.1
4 / High / 5 / 100 / 44.9
5 / High / 15 / 150 / 17.4
6 / High / 5 / 150 / 54.9
7 / Low / 5 / 125 / 52.5
8 / High / 15 / 100 / 5.37
9 / Low / 5 / 150 / 61.2
10 / High / 5 / 100 / 50.5
11 / Low / 5 / 100 / 48.6
12 / High / 15 / 150 / 20.2
13 / High / 10 / 125 / 43.2
14 / Low / 15 / 125 / 40
15 / Low / 15 / 100 / 14.6
16 / Low / 10 / 150 / 49.5

Table S2: ANOVA analysis for measured responses.

Response / Source / DF / Sum of squares / Mean square / F ratio / P value
C1 / Model / 8 / 4004 / 501 / 16.6 / 0.0007*
C2 / Error / 7 / 212 / 30.2
C3 / Total error / 15 / 4216

2. Preparation of the multilayered microparticles

The preparation of the single layer microparticles (SLMPs), double layer microparticles (DLMPs), and triple layer microparticles (TLMPs) by layer-by-layer is shown in Figure S1. The multilayer particles are obtained by alternately coating alginate (AG) and thiolated chitosan (TCS) on the surface of the alginate microparticle

Figure S1. Schematic preparation scheme of the thiolated chitosan (TCS) coated multilayer microparticles (MPs).

4. Percent drug loading determination using 31P Solid-State NMR

31P-P90 MAS solid-state NMR spectra are acquired on a Tecmag Apollo console (Houston, TX) with 8.45 T magnet and homebuilt, 2-channel, wide-bore NMR probes. The 1H and 31P Larmor frequencies were 357.2 MHz and 144.596 MHz, respectively. The 31P spectra are acquired on 3 mm probe with MAS spinning frequency and 45º pulse length of 8 KHz and 2 μs, respectively. The signals are represented as chemical shift value; δ: ppm. About 40 mg of the MPs sample is analyzed.drsezaQ All experiments are performed at ambient temperature without any corrections for sample heating.

3. In vitro drug release kinetic models

In order to investigate the mechanism of drug release from the MPs, various kinetics models (First-order, Higuchi, Baker-Lonsdale, and Korsmeyer–Peppas model) are used to fit the data distributions. The equation and parameters of these models are shown in Table S3

Table S3: Different release models for model fit analysis of the in vitro data

Model / Equation / Parameter(s)
First-order / F=100 · (1-e-k1 · t) / k1
Higuchi / F=kH · t0.5 / kH
Baker-Lonsdale / / kBL
Korsmeyer–Peppas / F=kKP · tn / kKP, n

F represents the fraction of the drug released in time t, k1, kH, kBL, kKP represent the release rate constant of different model, n is the release exponent.